{"id":12345,"date":"2026-03-02T06:13:31","date_gmt":"2026-03-02T06:13:31","guid":{"rendered":"https:\/\/hlh-js.com\/?p=12345"},"modified":"2026-03-02T06:27:18","modified_gmt":"2026-03-02T06:27:18","slug":"plastic-media-vs-walnut-shell-which-is-better","status":"publish","type":"post","link":"https:\/\/hlh-js.com\/ja\/resource\/blog\/plastic-media-vs-walnut-shell-which-is-better\/","title":{"rendered":"Plastic Media vs Walnut Shell: Which Is Better?"},"content":{"rendered":"<!-- ============================================================\n     CLUSTER ARTICLE #14 \u2014 WordPress Post Content\n     Title: Plastic Media vs Walnut Shell: Which Is Better?\n     \u7c98\u8d34\u65b9\u5f0f\uff1aGutenberg\u300c\u81ea\u5b9a\u4e49 HTML\u300d\u5757 \u6216 \u7ecf\u5178\u7f16\u8f91\u5668\u300c\u6587\u672c\u300d\u6a21\u5f0f\n     ============================================================ -->\n\n<style>\n\/* \u2500\u2500 \u5bf9\u6bd4\u4e3b\u9898\uff1a\u5de5\u4e1a\u84dd \u00d7 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0}\n\n@media(max-width:680px){\n  .pm-vs-header{grid-template-columns:1fr;gap:2px}\n  .pm-vs-divider{padding:8px;writing-mode:horizontal-tb}\n  .pm-scorecard{grid-template-columns:1fr}\n  .pm-cost-grid{grid-template-columns:1fr}\n  .pm-moisture-grid{grid-template-columns:1fr}\n  .pm-h2h-row{grid-template-columns:1fr}\n  .pm-h2h-cell.prop{border-right:none;background:#1c1917;color:#e7e5e4}\n}\n@media(max-width:480px){\n  .pm-decision-grid{grid-template-columns:1fr}\n  .pm-prop-bars-inner{grid-template-columns:1fr}\n}\n<\/style>\n\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\n     INTRO\n\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h1>Plastic Media vs Walnut Shell: Which Is Better?<\/h1>\n<p>Plastic blast media and walnut shell grit are the two most commonly considered &#8220;gentle&#8221; abrasives for stripping coatings from sensitive substrates \u2014 and the comparison between them comes up constantly among automotive restorers, aerospace maintenance technicians, mold cleaners, and anyone choosing between them for the first time. Both are softer than mineral abrasives. Both remove paint without the substrate damage risks of silica sand or aluminum oxide. Both can be used in standard pressure blast equipment. On the surface, they seem interchangeable.<\/p>\n\n<p>They are not. The differences in hardness, moisture sensitivity, contamination behavior, regulatory classification, and reusability are significant enough that the correct choice for one application is definitively the wrong choice for another. Choosing walnut shell for an aerospace aluminum structure can introduce organic contamination that causes anodize adhesion failures. Choosing plastic media for a wet gun-barrel cleaning application wastes money on a media specification far beyond what the application requires. Getting this choice right matters \u2014 and this guide gives you the complete technical basis to make it correctly.<\/p>\n\n<p>This comparison covers every dimension that separates these two media types: physical properties, blast performance characteristics, substrate compatibility, moisture behavior, cost and reusability economics, regulatory considerations, and specific application recommendations. The goal is not a generic &#8220;plastic media wins&#8221; conclusion but an honest, application-specific answer to the question operators actually face in practice.For a broader overview of the full plastic media category, see: <a href=\"https:\/\/hlh-js.com\/resource\/blog\/what-is-plastic-media-the-complete-guide-to-types-uses-applications\/\">What Is Plastic Media? The Complete Guide<\/a>.<\/p>\n\n\n<!-- TOC -->\n<nav class=\"pm-toc\" aria-label=\"Table of Contents\">\n  <p class=\"pm-toc-title\">\ud83d\udccb Table of Contents<\/p>\n  <ol>\n    <li><a href=\"#wv-overview\">At a Glance: What Each Media Is<\/a><\/li>\n    <li><a href=\"#wv-properties\">Physical Properties Head-to-Head<\/a><\/li>\n    <li><a href=\"#wv-bars\">Performance Comparison Across Key Dimensions<\/a><\/li>\n    <li><a href=\"#wv-substrate\">Substrate Compatibility: Where Each Excels and Fails<\/a><\/li>\n    <li><a href=\"#wv-moisture\">Moisture Sensitivity: A Critical Difference<\/a><\/li>\n    <li><a href=\"#wv-contamination\">Contamination Behavior and Surface Cleanliness<\/a><\/li>\n    <li><a href=\"#wv-reuse\">Reusability and Media Life<\/a><\/li>\n    <li><a href=\"#wv-cost\">Total Cost of Ownership Comparison<\/a><\/li>\n    <li><a href=\"#wv-regulatory\">Regulatory and Disposal Considerations<\/a><\/li>\n    <li><a href=\"#wv-applications\">Application-by-Application Decision Guide<\/a><\/li>\n    <li><a href=\"#wv-scorecard\">Overall Scorecard<\/a><\/li>\n    <li><a href=\"#wv-faq\">\u3088\u304f\u3042\u308b\u8cea\u554f<\/a><\/li>\n    <li><a href=\"#wv-related\">Related Guides<\/a><\/li>\n  <\/ol>\n<\/nav>\n\n\n<!-- VS HEADER VISUAL -->\n<div class=\"pm-vs-header\">\n  <div class=\"pm-vs-left\">\n    <div class=\"pm-vs-label\">Engineered Synthetic<\/div>\n    <div class=\"pm-vs-name\">Plastic Blast Media<\/div>\n    <div class=\"pm-vs-sub\">Thermoset polymer \u00b7 Urea, melamine, or acrylic \u00b7 Manufactured to specification<\/div>\n  <\/div>\n  <div class=\"pm-vs-divider\">VS<\/div>\n  <div class=\"pm-vs-right\">\n    <div class=\"pm-vs-label\">Agricultural Byproduct<\/div>\n    <div class=\"pm-vs-name\">Walnut Shell Grit<\/div>\n    <div class=\"pm-vs-sub\">Crushed Juglans regia shell \u00b7 Natural organic \u00b7 Grade-specified by mesh<\/div>\n  <\/div>\n<\/div>\n\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\n     S1 \u2014 OVERVIEW\n\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"wv-overview\">At a Glance: What Each Media Is<\/h2>\n\n<p><strong>Plastic blast media<\/strong> is a precision-manufactured thermoset polymer abrasive produced in three primary chemistries: urea formaldehyde (Type II), melamine formaldehyde (Type III), and acrylic\/PMMA (Type V). Each type is manufactured from controlled polymer feedstocks, ground or shaped to specified particle geometries, and classified to tight mesh tolerances. Physical properties \u2014 hardness, density, moisture content, pH \u2014 are tested and documented per MIL-P-85891A for aerospace and defense applications, and to equivalent commercial specifications for industrial use. The consistency of the manufactured product is its defining characteristic: every bag of Mesh 20 Type II urea from a qualified supplier has essentially the same particle size distribution, hardness, and chemical composition as the last.<\/p>\n\n<p><strong>Walnut shell grit<\/strong> is produced by crushing, drying, and classifying the hard shells of English walnuts (<em>Juglans regia<\/em>). The shell is ground to angular particles, sized by screen classification to standard mesh grades (typically Mesh 8 through 40\/50), and dried to controlled moisture content before packaging. Walnut shell is a naturally occurring organic material \u2014 its properties are fundamentally agricultural. Hardness, particle shape, and density are consistent within a species and grade, but less tightly controlled than engineered plastics. The product varies by growing region, harvest season, and processing quality.<\/p>\n\n<div class=\"pm-callout pm-callout-blue\">\n  <strong>The fundamental character difference:<\/strong> Plastic media is an engineered industrial product with controlled, documentable properties. Walnut shell is an agricultural byproduct with good-but-variable properties. This distinction matters most in regulated applications \u2014 aerospace, defense, food contact \u2014 where documented material traceability and consistent performance are requirements, not preferences.\n<\/div>\n\n<hr class=\"pm-section-divider\">\n\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\n     S2 \u2014 PHYSICAL PROPERTIES H2H\n\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"wv-properties\">Physical Properties Head-to-Head<\/h2>\n\n<div class=\"pm-h2h\">\n  <div class=\"pm-h2h-row header\">\n    <div class=\"pm-h2h-cell\">Property<\/div>\n    <div class=\"pm-h2h-cell\">\u30d7\u30e9\u30b9\u30c1\u30c3\u30af\u30fb\u30e1\u30c7\u30a3\u30a2<\/div>\n    <div class=\"pm-h2h-cell\">Walnut Shell<\/div>\n  <\/div>\n  <div class=\"pm-h2h-row\">\n    <div class=\"pm-h2h-cell prop\">Mohs hardness<\/div>\n    <div class=\"pm-h2h-cell plastic\">2.5\u20134.0 (varies by type: Acrylic ~3.0, Urea ~3.5, Melamine ~4.0)<\/div>\n    <div class=\"pm-h2h-cell walnut\">3.0\u20134.0 (varies by grade and moisture content; dry shell toward upper end)<\/div>\n  <\/div>\n  <div class=\"pm-h2h-row\">\n    <div class=\"pm-h2h-cell prop\">\u5d69\u5bc6\u5ea6<\/div>\n    <div class=\"pm-h2h-cell plastic\">40\u201355 lb\/ft\u00b3 (varies by type: acrylic lighter, melamine denser) <span class=\"pm-winner-p\">\u2713 more consistent<\/span><\/div>\n    <div class=\"pm-h2h-cell walnut\">35\u201350 lb\/ft\u00b3 (variable \u2014 hollow shell fragments alter density)<\/div>\n  <\/div>\n  <div class=\"pm-h2h-row\">\n    <div class=\"pm-h2h-cell prop\">\u7c92\u5b50\u5f62\u72b6<\/div>\n    <div class=\"pm-h2h-cell plastic\">Controlled irregular angular (manufactured); consistent shape per lot <span class=\"pm-winner-p\">\u2713 wins<\/span><\/div>\n    <div class=\"pm-h2h-cell walnut\">Irregular angular; natural variation in shape; some flat fragment pieces in each lot<\/div>\n  <\/div>\n  <div class=\"pm-h2h-row\">\n    <div class=\"pm-h2h-cell prop\">Specific gravity<\/div>\n    <div class=\"pm-h2h-cell plastic\">1.2\u20131.5 g\/cm\u00b3<\/div>\n    <div class=\"pm-h2h-cell walnut\">1.2\u20131.4 g\/cm\u00b3 <span class=\"pm-winner-tie\">\u2248 similar<\/span><\/div>\n  <\/div>\n  <div class=\"pm-h2h-row\">\n    <div class=\"pm-h2h-cell prop\">Moisture absorption<\/div>\n    <div class=\"pm-h2h-cell plastic\">Low to moderate; thermoset polymers absorb &lt;1\u20132% by weight at high humidity <span class=\"pm-winner-p\">\u2713 wins<\/span><\/div>\n    <div class=\"pm-h2h-cell walnut\">High; lignocellulosic material absorbs 8\u201315% moisture under humid conditions \u2014 significantly affects hardness and flow<\/div>\n  <\/div>\n  <div class=\"pm-h2h-row\">\n    <div class=\"pm-h2h-cell prop\">Hardness under humidity<\/div>\n    <div class=\"pm-h2h-cell plastic\">Minimal change; thermoset structure resists plasticization by moisture <span class=\"pm-winner-p\">\u2713 wins<\/span><\/div>\n    <div class=\"pm-h2h-cell walnut\">Significant softening; absorbed moisture reduces effective Mohs hardness by 0.5\u20131.0 units \u2014 measurably reduces strip rate<\/div>\n  <\/div>\n  <div class=\"pm-h2h-row\">\n    <div class=\"pm-h2h-cell prop\">Silica \/ free silica content<\/div>\n    <div class=\"pm-h2h-cell plastic\">Zero \u2014 inorganic silica-free polymer <span class=\"pm-winner-p\">\u2713 wins<\/span><\/div>\n    <div class=\"pm-h2h-cell walnut\">Trace levels; natural plant material may contain phytoliths (plant silica) \u2014 typically below occupational exposure limits but not zero<\/div>\n  <\/div>\n  <div class=\"pm-h2h-row\">\n    <div class=\"pm-h2h-cell prop\">Iron \/ metal content<\/div>\n    <div class=\"pm-h2h-cell plastic\">Zero \u2014 non-metallic polymer <span class=\"pm-winner-p\">\u2713 wins on contamination-critical apps<\/span><\/div>\n    <div class=\"pm-h2h-cell walnut\">Near zero \u2014 organic shell, no metallic content <span class=\"pm-winner-tie\">\u2248 tie<\/span><\/div>\n  <\/div>\n  <div class=\"pm-h2h-row\">\n    <div class=\"pm-h2h-cell prop\">Organic contamination risk<\/div>\n    <div class=\"pm-h2h-cell plastic\">None \u2014 inert polymer leaves no organic residue <span class=\"pm-winner-p\">\u2713 wins<\/span><\/div>\n    <div class=\"pm-h2h-cell walnut\">Present \u2014 tannins, juglone (natural phenolic compound in walnut), and organic dust remain on substrate and in crevices<\/div>\n  <\/div>\n  <div class=\"pm-h2h-row\">\n    <div class=\"pm-h2h-cell prop\">Specification standard<\/div>\n    <div class=\"pm-h2h-cell plastic\">MIL-P-85891A (aerospace\/defense); ASTM standards; manufacturer CoC <span class=\"pm-winner-p\">\u2713 wins<\/span><\/div>\n    <div class=\"pm-h2h-cell walnut\">No military specification; commercial grade only; ASTM B243 for general abrasive classification<\/div>\n  <\/div>\n  <div class=\"pm-h2h-row\">\n    <div class=\"pm-h2h-cell prop\">Mold \/ microbial risk<\/div>\n    <div class=\"pm-h2h-cell plastic\">None \u2014 inorganic polymer does not support microbial growth <span class=\"pm-winner-p\">\u2713 wins<\/span><\/div>\n    <div class=\"pm-h2h-cell walnut\">Present \u2014 moist walnut shell media in warm storage can develop mold within days; requires dry storage and use-within period<\/div>\n  <\/div>\n  <div class=\"pm-h2h-row\">\n    <div class=\"pm-h2h-cell prop\">Typical cost per pound<\/div>\n    <div class=\"pm-h2h-cell plastic\">$1.20\u2013$1.80\/lb (Type II urea); $1.80\u2013$2.80\/lb (Type V acrylic)<\/div>\n    <div class=\"pm-h2h-cell walnut\">$0.40\u2013$0.80\/lb <span class=\"pm-winner-w\">\u2713 wins on purchase price<\/span><\/div>\n  <\/div>\n<\/div>\n\n<hr class=\"pm-section-divider\">\n\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\n     S3 \u2014 PERFORMANCE BARS\n\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"wv-bars\">Performance Comparison Across Key Dimensions<\/h2>\n\n<div class=\"pm-prop-bars\">\n  <div class=\"pm-prop-row\">\n    <div class=\"pm-prop-label\">Strip Rate (coating removal speed at equivalent pressure)<\/div>\n    <div class=\"pm-prop-bars-inner\">\n      <div class=\"pm-prop-bar-wrap\">\n        <div class=\"pm-prop-bar-name plastic\">\u30d7\u30e9\u30b9\u30c1\u30c3\u30af\u30fb\u30e1\u30c7\u30a3\u30a2<\/div>\n        <div class=\"pm-prop-bar-track\"><div class=\"pm-prop-bar-fill plastic\" style=\"width:78%\">78% \u2014 High<\/div><\/div>\n      <\/div>\n      <div class=\"pm-prop-bar-wrap\">\n        <div class=\"pm-prop-bar-name walnut\">Walnut Shell<\/div>\n        <div class=\"pm-prop-bar-track\"><div class=\"pm-prop-bar-fill walnut\" style=\"width:65%\">65% \u2014 Moderate<\/div><\/div>\n      <\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-prop-row\">\n    <div class=\"pm-prop-label\">Substrate Safety (protection of sensitive substrates from damage)<\/div>\n    <div class=\"pm-prop-bars-inner\">\n      <div class=\"pm-prop-bar-wrap\">\n        <div class=\"pm-prop-bar-name plastic\">\u30d7\u30e9\u30b9\u30c1\u30c3\u30af\u30fb\u30e1\u30c7\u30a3\u30a2<\/div>\n        <div class=\"pm-prop-bar-track\"><div class=\"pm-prop-bar-fill plastic\" style=\"width:88%\">88% \u2014 Excellent<\/div><\/div>\n      <\/div>\n      <div class=\"pm-prop-bar-wrap\">\n        <div class=\"pm-prop-bar-name walnut\">Walnut Shell<\/div>\n        <div class=\"pm-prop-bar-track\"><div class=\"pm-prop-bar-fill walnut\" style=\"width:76%\">76% \u2014 Good<\/div><\/div>\n      <\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-prop-row\">\n    <div class=\"pm-prop-label\">Parameter Consistency (predictability across lots, humidity, storage conditions)<\/div>\n    <div class=\"pm-prop-bars-inner\">\n      <div class=\"pm-prop-bar-wrap\">\n        <div class=\"pm-prop-bar-name plastic\">\u30d7\u30e9\u30b9\u30c1\u30c3\u30af\u30fb\u30e1\u30c7\u30a3\u30a2<\/div>\n        <div class=\"pm-prop-bar-track\"><div class=\"pm-prop-bar-fill plastic\" style=\"width:92%\">92% \u2014 Excellent<\/div><\/div>\n      <\/div>\n      <div class=\"pm-prop-bar-wrap\">\n        <div class=\"pm-prop-bar-name walnut\">Walnut Shell<\/div>\n        <div class=\"pm-prop-bar-track\"><div class=\"pm-prop-bar-fill walnut\" style=\"width:58%\">58% \u2014 Moderate<\/div><\/div>\n      <\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-prop-row\">\n    <div class=\"pm-prop-label\">Surface Cleanliness After Blast (freedom from residual contamination)<\/div>\n    <div class=\"pm-prop-bars-inner\">\n      <div class=\"pm-prop-bar-wrap\">\n        <div class=\"pm-prop-bar-name plastic\">\u30d7\u30e9\u30b9\u30c1\u30c3\u30af\u30fb\u30e1\u30c7\u30a3\u30a2<\/div>\n        <div class=\"pm-prop-bar-track\"><div class=\"pm-prop-bar-fill plastic\" style=\"width:90%\">90% \u2014 Excellent<\/div><\/div>\n      <\/div>\n      <div class=\"pm-prop-bar-wrap\">\n        <div class=\"pm-prop-bar-name walnut\">Walnut Shell<\/div>\n        <div class=\"pm-prop-bar-track\"><div class=\"pm-prop-bar-fill walnut\" style=\"width:62%\">62% \u2014 Fair (tannin\/juglone residue)<\/div><\/div>\n      <\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-prop-row\">\n    <div class=\"pm-prop-label\">Reusability (cycles achievable with reclaim system)<\/div>\n    <div class=\"pm-prop-bars-inner\">\n      <div class=\"pm-prop-bar-wrap\">\n        <div class=\"pm-prop-bar-name plastic\">\u30d7\u30e9\u30b9\u30c1\u30c3\u30af\u30fb\u30e1\u30c7\u30a3\u30a2<\/div>\n        <div class=\"pm-prop-bar-track\"><div class=\"pm-prop-bar-fill plastic\" style=\"width:80%\">4\u20138\u00d7 reuse cycles<\/div><\/div>\n      <\/div>\n      <div class=\"pm-prop-bar-wrap\">\n        <div class=\"pm-prop-bar-name walnut\">Walnut Shell<\/div>\n        <div class=\"pm-prop-bar-track\"><div class=\"pm-prop-bar-fill walnut\" style=\"width:50%\">2\u20134\u00d7 reuse cycles<\/div><\/div>\n      <\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-prop-row\">\n    <div class=\"pm-prop-label\">Purchase Price (lower is better \u2014 walnut shell wins on raw cost)<\/div>\n    <div class=\"pm-prop-bars-inner\">\n      <div class=\"pm-prop-bar-wrap\">\n        <div class=\"pm-prop-bar-name plastic\">\u30d7\u30e9\u30b9\u30c1\u30c3\u30af\u30fb\u30e1\u30c7\u30a3\u30a2<\/div>\n        <div class=\"pm-prop-bar-track\"><div class=\"pm-prop-bar-fill plastic\" style=\"width:40%\">$1.20\u2013$1.80\/lb<\/div><\/div>\n      <\/div>\n      <div class=\"pm-prop-bar-wrap\">\n        <div class=\"pm-prop-bar-name walnut\">Walnut Shell<\/div>\n        <div class=\"pm-prop-bar-track\"><div class=\"pm-prop-bar-fill walnut\" style=\"width:22%\">$0.40\u2013$0.80\/lb<\/div><\/div>\n      <\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-prop-row\">\n    <div class=\"pm-prop-label\">Moisture Resistance (performance stability in humid conditions)<\/div>\n    <div class=\"pm-prop-bars-inner\">\n      <div class=\"pm-prop-bar-wrap\">\n        <div class=\"pm-prop-bar-name plastic\">\u30d7\u30e9\u30b9\u30c1\u30c3\u30af\u30fb\u30e1\u30c7\u30a3\u30a2<\/div>\n        <div class=\"pm-prop-bar-track\"><div class=\"pm-prop-bar-fill plastic\" style=\"width:85%\">85% \u2014 Good<\/div><\/div>\n      <\/div>\n      <div class=\"pm-prop-bar-wrap\">\n        <div class=\"pm-prop-bar-name walnut\">Walnut Shell<\/div>\n        <div class=\"pm-prop-bar-track\"><div class=\"pm-prop-bar-fill walnut\" style=\"width:30%\">30% \u2014 Poor (absorbs 8\u201315% moisture)<\/div><\/div>\n      <\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-prop-row\">\n    <div class=\"pm-prop-label\">Regulatory Acceptance (specification standards, traceability, aerospace approval)<\/div>\n    <div class=\"pm-prop-bars-inner\">\n      <div class=\"pm-prop-bar-wrap\">\n        <div class=\"pm-prop-bar-name plastic\">\u30d7\u30e9\u30b9\u30c1\u30c3\u30af\u30fb\u30e1\u30c7\u30a3\u30a2<\/div>\n        <div class=\"pm-prop-bar-track\"><div class=\"pm-prop-bar-fill plastic\" style=\"width:95%\">95% \u2014 MIL-P-85891A, full CoC<\/div><\/div>\n      <\/div>\n      <div class=\"pm-prop-bar-wrap\">\n        <div class=\"pm-prop-bar-name walnut\">Walnut Shell<\/div>\n        <div class=\"pm-prop-bar-track\"><div class=\"pm-prop-bar-fill walnut\" style=\"width:35%\">35% \u2014 Commercial grade only<\/div><\/div>\n      <\/div>\n    <\/div>\n  <\/div>\n<\/div>\n\n<hr class=\"pm-section-divider\">\n\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\n     S4 \u2014 SUBSTRATE COMPATIBILITY\n\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"wv-substrate\">Substrate Compatibility: Where Each Excels and Fails<\/h2>\n\n<div class=\"pm-table-wrap\">\n  <table>\n    <thead>\n      <tr>\n        <th>Substrate<\/th>\n        <th>\u30d7\u30e9\u30b9\u30c1\u30c3\u30af\u30fb\u30e1\u30c7\u30a3\u30a2<\/th>\n        <th>Walnut Shell<\/th>\n        <th>Recommended Choice<\/th>\n      <\/tr>\n    <\/thead>\n    <tbody>\n      <tr>\n        <td>Aluminum aircraft structure (2024, 6061, 7075)<\/td>\n        <td>\u2705 Excellent \u2014 full aerospace process specification support; zero organic contamination; qualifiable per Almen strip test<\/td>\n        <td>\u26a0\ufe0f Acceptable at low pressures but lacks MIL-spec traceability; tannin residue risks anodize adhesion issues; not approved in most aerospace process specs<\/td>\n        <td><strong>\u30d7\u30e9\u30b9\u30c1\u30c3\u30af\u30fb\u30e1\u30c7\u30a3\u30a2<\/strong><\/td>\n      <\/tr>\n      <tr>\n        <td>CFRP \/ composite aircraft structure<\/td>\n        <td>\u2705 Type V acrylic is the only approved media for CFRP depainting in most aerospace NDI protocols<\/td>\n        <td>\u274c Not appropriate \u2014 insufficient specification control; organic contamination risk; no qualified aerospace process data for composite depainting<\/td>\n        <td><strong>Plastic Media (Type V only)<\/strong><\/td>\n      <\/tr>\n      <tr>\n        <td>Automotive steel body panels<\/td>\n        <td>\u2705 Excellent \u2014 consistent parameters; clean substrate for primer; reclaim economical at production volume<\/td>\n        <td>\u2705 Good \u2014 effective at moderate pressures; acceptable for hobby\/restoration use where MIL-spec not required; lower initial cost<\/td>\n        <td><strong>\u30d7\u30e9\u30b9\u30c1\u30c3\u30af\u30fb\u30e1\u30c7\u30a3\u30a2<\/strong> for production; walnut acceptable for occasional restoration<\/td>\n      <\/tr>\n      <tr>\n        <td>Injection molds and die casting tools<\/td>\n        <td>\u2705 Excellent \u2014 Type V acrylic preserves polished cavity Ra; zero organic residue that could affect mold release or part surface<\/td>\n        <td>\u274c Not recommended \u2014 organic tannin residue in cavity; hardness variability affects Ra consistency; no established process qualification for mold cleaning<\/td>\n        <td><strong>Plastic Media (Type V)<\/strong><\/td>\n      <\/tr>\n      <tr>\n        <td>Firearms (external bluing removal, barrel cleaning)<\/td>\n        <td>\u2705 Effective; zero contamination; good surface profile for re-bluing or Parkerizing<\/td>\n        <td>\u2705 Traditional and effective for firearms cleaning; well-established in gunsmithing; gentle on external wood or synthetic stock components<\/td>\n        <td><strong>Either<\/strong> \u2014 walnut shell has strong traditional application here; plastic media preferred for any subsequent regulated finish<\/td>\n      <\/tr>\n      <tr>\n        <td>Wooden surfaces (furniture stripping)<\/td>\n        <td>\u26a0\ufe0f Works at very low pressures but can raise wood grain aggressively; no organic compatibility advantage<\/td>\n        <td>\u2705 Better fit \u2014 organic-compatible; lower Mohs when moist (protective on soft wood); traditional media for wood refinishing<\/td>\n        <td><strong>Walnut Shell<\/strong><\/td>\n      <\/tr>\n      <tr>\n        <td>Painted brick \/ masonry<\/td>\n        <td>\u26a0\ufe0f Too aggressive for soft brick; acceptable for dense concrete at higher pressures<\/td>\n        <td>\u2705 Better for soft brick \u2014 lower effective hardness, especially when slightly moist; less substrate erosion risk on porous masonry<\/td>\n        <td><strong>Walnut Shell<\/strong> for soft brick; plastic for dense masonry<\/td>\n      <\/tr>\n      <tr>\n        <td>Boat hull (fiberglass)<\/td>\n        <td>\u2705 Excellent \u2014 consistent results; clean surface for gelcoat or antifouling<\/td>\n        <td>\u2705 Acceptable \u2014 effective for antifouling paint removal; lower cost per square foot; tannin residue from walnut must be washed before gelcoat application<\/td>\n        <td><strong>\u30d7\u30e9\u30b9\u30c1\u30c3\u30af\u30fb\u30e1\u30c7\u30a3\u30a2<\/strong> preferred; walnut shell acceptable if thorough post-blast wash is performed<\/td>\n      <\/tr>\n      <tr>\n        <td>Electronics \/ IC packages<\/td>\n        <td>\u2705 Type V acrylic specifically qualified for electronics deflashing; fine mesh to 80<\/td>\n        <td>\u274c Not appropriate \u2014 organic debris embeds in fine contact features; no fine enough mesh grade; no aerospace\/electronics qualification<\/td>\n        <td><strong>Plastic Media (Type V only)<\/strong><\/td>\n      <\/tr>\n    <\/tbody>\n  <\/table>\n<\/div>\n\n<hr class=\"pm-section-divider\">\n\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\n     S5 \u2014 MOISTURE SENSITIVITY\n\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"wv-moisture\">Moisture Sensitivity: A Critical Difference<\/h2>\n\n<p>Moisture sensitivity is the single most operationally significant difference between plastic blast media and walnut shell grit \u2014 and the one most likely to produce inconsistent results in real-world shop environments where humidity is not controlled.<\/p>\n\n<div class=\"pm-moisture-grid\">\n  <div class=\"pm-moisture-card\">\n    <div class=\"pm-moisture-head plastic\">\ud83d\udd35 Plastic Media \u2014 Moisture Behavior<\/div>\n    <div class=\"pm-moisture-body\">\n      <ul>\n        <li>Thermoset polymer structure resists moisture absorption \u2014 typically &lt;1\u20132% weight gain even at 90% RH<\/li>\n        <li>Hardness essentially unchanged by moisture \u2014 Mohs hardness is a function of the polymer cross-link density, not hydration state<\/li>\n        <li>Clumping can occur at very high moisture (above ~3% by weight) \u2014 manifests as flow irregularity in the blast pot<\/li>\n        <li>MIL-P-85891A specifies maximum moisture content of 1.0% for Type II urea \u2014 testable with simple gravimetric method<\/li>\n        <li>Storage requirement: keep sealed in original bags until use; store above floor level in a dry area; do not store near steam lines or water sources<\/li>\n        <li>Recovery from wet storage: dry at 100\u2013120\u00b0F for 2\u20134 hours; full properties restored<\/li>\n      <\/ul>\n    <\/div>\n  <\/div>\n  <div class=\"pm-moisture-card\">\n    <div class=\"pm-moisture-head walnut\">\ud83d\udfe4 Walnut Shell \u2014 Moisture Behavior<\/div>\n    <div class=\"pm-moisture-body\">\n      <ul>\n        <li>Lignocellulosic (wood-based) structure absorbs moisture readily \u2014 8\u201315% weight gain at moderate humidity levels (60\u201380% RH)<\/li>\n        <li>Hardness decreases measurably as moisture increases \u2014 Mohs hardness can drop 0.5\u20131.0 units when thoroughly wet, reducing strip rate by 20\u201335%<\/li>\n        <li>Clumping occurs at much lower moisture levels than plastic media \u2014 wet walnut shell bridging in blast pots is a common operational problem<\/li>\n        <li>No military specification moisture limit \u2014 commercial grade variations can enter the market at inconsistent moisture content<\/li>\n        <li>Storage requirement: sealed containers; climate-controlled storage strongly preferred; use within 6 months of manufacturing date<\/li>\n        <li>Mold risk: moist walnut shell in warm conditions (&gt;75\u00b0F, &gt;60% RH) can develop mold within 48\u201372 hours \u2014 making it unusable and potentially an occupational health hazard<\/li>\n        <li>Recovery from wet storage: dry at 120\u2013140\u00b0F; however, repeated wet\/dry cycles degrade particle integrity faster than plastic media<\/li>\n      <\/ul>\n    <\/div>\n  <\/div>\n<\/div>\n\n<div class=\"pm-callout pm-callout-warn\">\n  <strong>The operational consequence of walnut shell moisture sensitivity:<\/strong> In a shop without climate-controlled media storage, a bag of walnut shell opened on a humid summer day in a Southern or coastal facility may have absorbed enough moisture to reduce strip rate by 25% before the first blast trigger is pulled. The operator sees slower-than-expected performance, increases pressure, and risks substrate damage \u2014 without understanding that the media itself has changed from the dry-season baseline. Plastic media does not have this problem to the same degree.\n<\/div>\n\n<hr class=\"pm-section-divider\">\n\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\n     S6 \u2014 CONTAMINATION\n\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"wv-contamination\">Contamination Behavior and Surface Cleanliness<\/h2>\n\n<p>The contamination profiles of these two media types are fundamentally different, and the practical implications depend entirely on what the blasted surface will be used for.<\/p>\n\n<h3>Plastic Media Contamination Profile<\/h3>\n<p>Plastic blast media leaves an inert polymer substrate \u2014 no organic compounds, no metallic content, no reactive chemistry. Residual plastic media particles on the blasted surface are visible white specks that blow off cleanly with compressed air. The bare metal surface after plastic media blasting is chemically clean: no tannins, no phenolics, no organic residue from the media itself. The only contamination concern is from the coating debris removed during blasting \u2014 and that is a property of the stripped coating, not the media. For anodizing, plating, painting, and any application where chemical surface cleanliness is specified, a plastic-media-blasted surface requires only standard compressed air blow-off before processing.<\/p>\n\n<h3>Walnut Shell Contamination Profile<\/h3>\n<p>Walnut shell produces a more complex surface chemistry. The shell of <em>Juglans regia<\/em> naturally contains tannins (polyphenolic compounds) and juglone (5-hydroxy-1,4-naphthalenedione), a phenolic compound with well-documented inhibitory effects on some biological processes. These compounds transfer from the shell particles to the blasted surface during impact \u2014 a thin film of organic residue that is not visible to the naked eye but is detectable by contact angle measurement, FTIR spectroscopy, or more practically, by the behavior of subsequent coating applications.<\/p>\n\n<p>The practical implications of walnut shell organic residue on the substrate:<\/p>\n\n<div class=\"pm-table-wrap\">\n  <table>\n    <thead>\n      <tr>\n        <th>Subsequent Process<\/th>\n        <th>Effect of Walnut Shell Organic Residue<\/th>\n        <th>Mitigation<\/th>\n      <\/tr>\n    <\/thead>\n    <tbody>\n      <tr>\n        <td>Anodizing (aluminum)<\/td>\n        <td>Tannin residue on aluminum surface causes non-uniform anodize oxide formation \u2014 visible as mottling, dark spots, or uneven color in the anodize layer<\/td>\n        <td>Full degreasing + etching in anodize pre-treatment sequence may not fully remove tannin contamination from porous or textured surfaces. Not recommended for cosmetic anodize.<\/td>\n      <\/tr>\n      <tr>\n        <td>\u96fb\u6c17\u3081\u3063\u304d<\/td>\n        <td>Organic residue interferes with zincate adhesion layer formation on aluminum, reducing plating adhesion. On steel, tannin residue can prevent uniform electrodeposition.<\/td>\n        <td>Requires aggressive pre-treatment (anodic cleaning, acid pickle) that may be incompatible with tight-tolerance parts. Avoid walnut shell for pre-plate blasting.<\/td>\n      <\/tr>\n      <tr>\n        <td>Epoxy primer application<\/td>\n        <td>Minimal impact if thorough blow-off and IPA wipe are performed. Epoxy primers are relatively tolerant of light organic contamination.<\/td>\n        <td>Standard blow-off + IPA wipe typically sufficient. Acceptable for automotive restoration use.<\/td>\n      <\/tr>\n      <tr>\n        <td>Powder coating<\/td>\n        <td>Tannin residue can cause adhesion reduction in some powder coat chemistries \u2014 particularly polyester powder over aluminum. Outgassing from trapped organic residue can cause pinholes.<\/td>\n        <td>Thorough blow-off + solvent wipe before powder coat application. For high-value powder coat work, prefer plastic media.<\/td>\n      <\/tr>\n      <tr>\n        <td>Food contact surfaces<\/td>\n        <td>Juglone is a naturally occurring toxin \u2014 not approved for contact with food processing surfaces. Walnut shell is inappropriate for cleaning food-contact equipment.<\/td>\n        <td>Use plastic media only for food processing equipment and any surface that will contact food or beverage.<\/td>\n      <\/tr>\n    <\/tbody>\n  <\/table>\n<\/div>\n\n<hr class=\"pm-section-divider\">\n\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\n     S7 \u2014 REUSABILITY\n\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"wv-reuse\">Reusability and Media Life<\/h2>\n\n<p>Both media types are reusable through a reclaim system, but the number of productive cycles and the reclaim system requirements differ significantly.<\/p>\n\n<p>Plastic blast media achieves 4\u20138 productive cycles in a well-calibrated reclaim operation. The thermoset polymer fractures into predictable smaller fragments that maintain angular geometry and cutting effectiveness through multiple cycles. The reclaim air wash can cleanly separate plastic media fines from usable particles because the density and size difference between usable media and fracture debris is relatively consistent and predictable. Media degradation is gradual and detectable through periodic sieve analysis.<\/p>\n\n<p>Walnut shell achieves 2\u20134 productive cycles under comparable conditions. The lignocellulosic structure fractures less predictably than engineered polymer \u2014 producing a wider distribution of fragment sizes and shapes, including thin flat flakes that have very different air-wash separation characteristics than the remaining angular particles. The reclaim air wash calibration is more difficult for walnut shell than for plastic media because the density and shape variation within the &#8220;usable&#8221; fraction is larger. Additionally, walnut shell absorbs moisture during use, which changes its weight and therefore its behavior in the air wash \u2014 requiring more frequent recalibration as ambient humidity changes seasonally.<\/p>\n\n<p>Walnut shell also has a practical shelf life limitation that plastic media does not: stored walnut shell can develop mold in warm, humid conditions, rendering the media unusable. Plastic media does not support microbial growth and has no mold-related shelf life limit under reasonable storage conditions.<\/p>\n\n<hr class=\"pm-section-divider\">\n\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\n     S8 \u2014 COST COMPARISON\n\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"wv-cost\">Total Cost of Ownership Comparison<\/h2>\n\n<p>Walnut shell&#8217;s lower purchase price is real \u2014 typically 40\u201360% less per pound than Type II urea plastic media. But purchase price is not the same as total cost of ownership when reclaim systems are in play. The full economic comparison requires accounting for reuse cycles, waste disposal volume, and the rework cost when surface contamination from walnut shell organic residue causes coating adhesion failures.<\/p>\n\n<div class=\"pm-cost-grid\">\n  <div class=\"pm-cost-card\">\n    <div class=\"pm-cost-head plastic\">\ud83d\udd35 Plastic Media \u2014 Cost Analysis<\/div>\n    <div class=\"pm-cost-body\">\n      <div class=\"pm-cost-row\"><span class=\"pm-cost-label\">Purchase price per lb (Type II)<\/span><span class=\"pm-cost-val\">$1.20\u2013$1.80<\/span><\/div>\n      <div class=\"pm-cost-row\"><span class=\"pm-cost-label\">Reuse cycles (reclaim)<\/span><span class=\"pm-cost-val\">4\u20138\u00d7<\/span><\/div>\n      <div class=\"pm-cost-row\"><span class=\"pm-cost-label\">Effective cost per lb used<\/span><span class=\"pm-cost-val\">$0.18\u2013$0.45<\/span><\/div>\n      <div class=\"pm-cost-row\"><span class=\"pm-cost-label\">Disposal volume vs. no-reclaim<\/span><span class=\"pm-cost-val\">75\u201385% reduction<\/span><\/div>\n      <div class=\"pm-cost-row\"><span class=\"pm-cost-label\">Coating adhesion rework rate<\/span><span class=\"pm-cost-val\">Very low (clean surface)<\/span><\/div>\n      <div class=\"pm-cost-row\"><span class=\"pm-cost-label\">Moisture-related waste incidents<\/span><span class=\"pm-cost-val\">Rare<\/span><\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-cost-card\">\n    <div class=\"pm-cost-head walnut\">\ud83d\udfe4 Walnut Shell \u2014 Cost Analysis<\/div>\n    <div class=\"pm-cost-body\">\n      <div class=\"pm-cost-row\"><span class=\"pm-cost-label\">Purchase price per lb<\/span><span class=\"pm-cost-val\">$0.40\u2013$0.80<\/span><\/div>\n      <div class=\"pm-cost-row\"><span class=\"pm-cost-label\">Reuse cycles (reclaim)<\/span><span class=\"pm-cost-val\">2\u20134\u00d7<\/span><\/div>\n      <div class=\"pm-cost-row\"><span class=\"pm-cost-label\">Effective cost per lb used<\/span><span class=\"pm-cost-val\">$0.13\u2013$0.40<\/span><\/div>\n      <div class=\"pm-cost-row\"><span class=\"pm-cost-label\">Disposal volume vs. no-reclaim<\/span><span class=\"pm-cost-val\">50\u201370% reduction<\/span><\/div>\n      <div class=\"pm-cost-row\"><span class=\"pm-cost-label\">Coating adhesion rework rate<\/span><span class=\"pm-cost-val\">Low\u2013moderate (tannin risk)<\/span><\/div>\n      <div class=\"pm-cost-row\"><span class=\"pm-cost-label\">Moisture-related waste incidents<\/span><span class=\"pm-cost-val\">Moderate (seasonal humidity)<\/span><\/div>\n    <\/div>\n  <\/div>\n<\/div>\n\n<div class=\"pm-callout pm-callout-green\">\n  <strong>The effective cost gap is much smaller than the purchase price suggests:<\/strong> When reclaim cycles are accounted for, walnut shell&#8217;s effective cost per pound used is approximately $0.13\u2013$0.40 vs. plastic media&#8217;s $0.18\u2013$0.45 \u2014 a gap of perhaps $0.05\u2013$0.15 per pound after reclaim. At 100 pounds per day, the cost difference is $5\u2013$15 per day. One coating adhesion rework on a single automotive panel \u2014 at $50\u2013$200 in labor and materials \u2014 erases weeks of that savings. The purchase price comparison is much less meaningful than it initially appears.\n<\/div>\n\n<hr class=\"pm-section-divider\">\n\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\n     S9 \u2014 REGULATORY\n\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"wv-regulatory\">Regulatory and Disposal Considerations<\/h2>\n\n<h3>Aerospace and Defense Specifications<\/h3>\n<p>MIL-P-85891A is the governing military specification for plastic blast media used in aerospace and defense applications. It defines test requirements for particle size, hardness, density, moisture content, pH, and other properties \u2014 and requires a Certificate of Conformance (CoC) from the manufacturer documenting actual test results for each lot. Plastic blast media from a qualified supplier is fully MIL-P-85891A compliant with full lot traceability.<\/p>\n\n<p>Walnut shell grit has no equivalent military specification. No MIL-P or equivalent document covers walnut shell grit as a blast media for aerospace applications. Some individual aerospace process specifications explicitly prohibit the use of walnut shell on structural components precisely because of this specification gap and the organic contamination concerns discussed above. If your customer, process specification, or quality system references any aerospace process standard that specifies blast media, verify whether walnut shell is permitted before use \u2014 many are not.<\/p>\n\n<h3>Waste Disposal<\/h3>\n<p>Spent media disposal classification follows the same principle for both media types: the coating residue mixed into the spent media determines regulatory status, not the media material itself. Spent media from operations removing chromate primer (D007 hazardous) or lead paint (D008 hazardous) must be characterized by TCLP testing regardless of whether the media is plastic or walnut shell. Neither material type provides a regulatory advantage in hazardous waste situations.<\/p>\n\n<p>For non-hazardous waste streams, both materials are typically classified as non-hazardous solid waste. One difference: walnut shell spent media can compost in landfills, whereas thermoset plastic media does not biodegrade. In jurisdictions with landfill regulations that incentivize or require organic waste diversion, walnut shell may have an advantage \u2014 though the volumes involved in most blast operations are small enough that this rarely matters in practice.<\/p>\n\n<hr class=\"pm-section-divider\">\n\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\n     S10 \u2014 APPLICATION DECISION GUIDE\n\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"wv-applications\">Application-by-Application Decision Guide<\/h2>\n\n<div class=\"pm-decision-grid\">\n  <div class=\"pm-decision-card\">\n    <div class=\"pm-decision-head use-plastic\">\u2708\ufe0f Aerospace Aluminum Structure <span class=\"pm-decision-badge\">Use Plastic<\/span><\/div>\n    <div class=\"pm-decision-body\">\n      MIL-P-85891A specification required by virtually all aerospace process documents. Zero tolerance for organic contamination before anodize or conversion coating. Almen strip documentation possible with plastic media.\n      <div class=\"pm-decision-reason\">Plastic media is the only defensible choice for any regulated aerospace application.<\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-decision-card\">\n    <div class=\"pm-decision-head use-plastic\">\ud83d\udee9\ufe0f CFRP \/ Composite Depainting <span class=\"pm-decision-badge\">Use Plastic<\/span><\/div>\n    <div class=\"pm-decision-body\">\n      Type V acrylic is the only media type approved in established aerospace NDI and composite repair processes. No walnut shell qualification data exists for composite structure depainting.\n      <div class=\"pm-decision-reason\">Type V acrylic plastic media only. No substitute.<\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-decision-card\">\n    <div class=\"pm-decision-head use-plastic\">\ud83d\udd27 Injection Mold Cleaning <span class=\"pm-decision-badge\">Use Plastic<\/span><\/div>\n    <div class=\"pm-decision-body\">\n      Tannin and juglone residue from walnut shell in polished mold cavity alters mold release chemistry and contaminates the first production parts after cleaning. Type V acrylic leaves zero residue.\n      <div class=\"pm-decision-reason\">Organic contamination risk from walnut shell is unacceptable for mold cavity cleaning.<\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-decision-card\">\n    <div class=\"pm-decision-head use-plastic\">\ud83d\udca1 Electronics Deflashing <span class=\"pm-decision-badge\">Use Plastic<\/span><\/div>\n    <div class=\"pm-decision-body\">\n      Fine mesh (60\u201380) Type V acrylic is the standard for IC package and connector deflashing. Walnut shell does not offer sufficiently fine mesh grades and introduces organic debris into contact features.\n      <div class=\"pm-decision-reason\">No walnut shell application exists for electronics deflashing.<\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-decision-card\">\n    <div class=\"pm-decision-head use-plastic\">\ud83d\ude97 Production Automotive Strip <span class=\"pm-decision-badge\">Use Plastic<\/span><\/div>\n    <div class=\"pm-decision-body\">\n      Consistent parameters across weather conditions, reclaim economics at volume, and clean substrate for primer application make plastic media the clear choice for shops stripping more than a few vehicles per week.\n      <div class=\"pm-decision-reason\">Economic and consistency advantage grows with production volume.<\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-decision-card\">\n    <div class=\"pm-decision-head use-plastic\">\ud83c\udf7d\ufe0f Food Processing Equipment <span class=\"pm-decision-badge\">Use Plastic<\/span><\/div>\n    <div class=\"pm-decision-body\">\n      Juglone in walnut shell is a naturally occurring bioactive compound not approved for contact with food-processing surfaces. Plastic media leaves an inert surface with no food-safety concerns.\n      <div class=\"pm-decision-reason\">Food safety regulations prohibit organic contamination from walnut shell.<\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-decision-card\">\n    <div class=\"pm-decision-head use-walnut\">\ud83d\udd2b Firearm Cleaning (Traditional) <span class=\"pm-decision-badge\">Walnut Acceptable<\/span><\/div>\n    <div class=\"pm-decision-body\">\n      Walnut shell has a long and well-established application in firearms cleaning and case tumbling. Works effectively on carbon fouling, powder residue, and tarnish on metal. Widely available in gunsmithing supply channels.\n      <div class=\"pm-decision-reason\">Walnut shell is the traditional choice; plastic media is also appropriate but offers no decisive advantage.<\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-decision-card\">\n    <div class=\"pm-decision-head use-walnut\">\ud83e\udeb5 Wood \/ Furniture Stripping <span class=\"pm-decision-badge\">Walnut Better<\/span><\/div>\n    <div class=\"pm-decision-body\">\n      Walnut shell&#8217;s moisture-variable hardness is actually an advantage on soft wood \u2014 wet media is gentler on the wood grain. Organic compatibility reduces risk of incompatibility with wood stains and oil finishes.\n      <div class=\"pm-decision-reason\">Natural organic material works with wood chemistry in a way synthetic polymer does not.<\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-decision-card\">\n    <div class=\"pm-decision-head use-either\">\ud83d\ude97 Hobby \/ Occasional Automotive <span class=\"pm-decision-badge\">Either Works<\/span><\/div>\n    <div class=\"pm-decision-body\">\n      For a hobbyist stripping one or two vehicles per year without a reclaim system, walnut shell&#8217;s lower purchase price provides a real economic benefit. Either media works acceptably at this scale.\n      <div class=\"pm-decision-reason\">Use walnut shell for lowest upfront cost; use plastic media if re-bluing or plating follows the blast.<\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-decision-card\">\n    <div class=\"pm-decision-head use-either\">\ud83d\udea2 Boat Hull Antifouling Removal <span class=\"pm-decision-badge\">Either, Plastic Preferred<\/span><\/div>\n    <div class=\"pm-decision-body\">\n      Both media types remove antifouling paint effectively from fiberglass hulls. Walnut shell requires thorough post-blast wash to remove tannin residue before new antifouling application. Plastic media needs only blow-off.\n      <div class=\"pm-decision-reason\">Plastic media is slightly cleaner; walnut shell is acceptable if washed before topcoat.<\/div>\n    <\/div>\n  <\/div>\n<\/div>\n\n<hr class=\"pm-section-divider\">\n\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\n     S11 \u2014 SCORECARD\n\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"wv-scorecard\">Overall Scorecard<\/h2>\n\n<div class=\"pm-scorecard\">\n  <div class=\"pm-score-col\">\n    <div class=\"pm-score-head plastic\">\ud83d\udd35 Plastic Media \u2014 Best For<\/div>\n    <div class=\"pm-score-body\">\n      <div class=\"pm-score-item\"><span class=\"si-icon\">\u2705<\/span><span class=\"si-text\">Any regulated aerospace or defense application \u2014 MIL-P-85891A is a hard requirement in most process specs<\/span><\/div>\n      <div class=\"pm-score-item\"><span class=\"si-icon\">\u2705<\/span><span class=\"si-text\">CFRP and composite structure \u2014 no substitute exists for Type V acrylic on fiber-reinforced composites<\/span><\/div>\n      <div class=\"pm-score-item\"><span class=\"si-icon\">\u2705<\/span><span class=\"si-text\">Injection mold cleaning \u2014 zero organic residue in cavity essential<\/span><\/div>\n      <div class=\"pm-score-item\"><span class=\"si-icon\">\u2705<\/span><span class=\"si-text\">Pre-anodize and pre-plate preparation \u2014 surface cleanliness demands inert media<\/span><\/div>\n      <div class=\"pm-score-item\"><span class=\"si-icon\">\u2705<\/span><span class=\"si-text\">Production automotive operations \u2014 reclaim economics and consistency advantage grow with volume<\/span><\/div>\n      <div class=\"pm-score-item\"><span class=\"si-icon\">\u2705<\/span><span class=\"si-text\">Humid climates or non-climate-controlled storage \u2014 moisture stability is essential<\/span><\/div>\n      <div class=\"pm-score-item\"><span class=\"si-icon\">\u2705<\/span><span class=\"si-text\">Food processing equipment \u2014 food-safe inert surface after blast<\/span><\/div>\n      <div class=\"pm-score-item\"><span class=\"si-icon\">\u2705<\/span><span class=\"si-text\">Any application requiring full material traceability and documented CoC<\/span><\/div>\n    <\/div>\n  <\/div>\n  <div class=\"pm-score-col\">\n    <div class=\"pm-score-head walnut\">\ud83d\udfe4 Walnut Shell \u2014 Best For<\/div>\n    <div class=\"pm-score-body\">\n      <div class=\"pm-score-item\"><span class=\"si-icon\">\u2705<\/span><span class=\"si-text\">Wood and furniture stripping \u2014 organic compatibility and moisture-variable hardness protect soft wood<\/span><\/div>\n      <div class=\"pm-score-item\"><span class=\"si-icon\">\u2705<\/span><span class=\"si-text\">Firearms cleaning \u2014 traditional, well-established application; widely available in gunsmithing channels<\/span><\/div>\n      <div class=\"pm-score-item\"><span class=\"si-icon\">\u2705<\/span><span class=\"si-text\">Soft masonry \/ historic brick \u2014 lower effective hardness is protective on fragile substrates<\/span><\/div>\n      <div class=\"pm-score-item\"><span class=\"si-icon\">\u2705<\/span><span class=\"si-text\">Hobby \/ occasional automotive restoration where reclaim system is not available or justified<\/span><\/div>\n      <div class=\"pm-score-item\"><span class=\"si-icon\">\u2705<\/span><span class=\"si-text\">Operations with very low volume where per-cycle media cost is more important than total cost of ownership<\/span><\/div>\n      <div class=\"pm-score-item\"><span class=\"si-icon\">\u2705<\/span><span class=\"si-text\">Applications where coating performance after blast is modest (not anodize, plate, or Class A paint)<\/span><\/div>\n    <\/div>\n  <\/div>\n<\/div>\n\n<div class=\"pm-callout\">\n  <strong>The honest summary:<\/strong> Plastic media is the better technical choice for the large majority of industrial, aerospace, and precision applications \u2014 its consistency, cleanliness, moisture resistance, and regulatory support make it the correct selection wherever the substrate is valuable, the subsequent coating is demanding, or the operation runs at any production scale. Walnut shell is a genuine and appropriate choice for hobby-scale restoration, firearms cleaning, wood stripping, and soft masonry applications where its organic character is neutral or advantageous and its lower purchase price provides real economic benefit at the volumes involved. The question is not which media is generally better \u2014 it is which media is correct for your specific application.\n<\/div>\n\n<hr class=\"pm-section-divider\">\n\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\n     FAQ\n\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<h2 id=\"wv-faq\">\u3088\u304f\u3042\u308b\u8cea\u554f<\/h2>\n\n<div itemscope itemtype=\"https:\/\/schema.org\/FAQPage\">\n\n  <div class=\"pm-faq-item\" itemscope itemprop=\"mainEntity\" itemtype=\"https:\/\/schema.org\/Question\">\n    <p class=\"pm-faq-q\" itemprop=\"name\">Can walnut shell grit damage steel or aluminum surfaces the way sand can?<\/p>\n    <div itemscope itemprop=\"acceptedAnswer\" itemtype=\"https:\/\/schema.org\/Answer\">\n      <p class=\"pm-faq-a\" itemprop=\"text\">At normal blast pressures, walnut shell grit does not produce the surface erosion, profile deepening, or substrate damage that silica sand causes on steel and aluminum. Its Mohs hardness of 3.0\u20134.0 is well below the hardness of steel (Mohs 4\u20135 for mild steel, higher for tool steels) and roughly equivalent to aluminum \u2014 giving it a similar gentle-abrasive character to plastic media on these substrates. However, walnut shell can cause thin steel panel distortion (oil-canning) at pressures above 45\u201350 PSI, similar to plastic media in that pressure range. On aluminum, walnut shell at moderate pressures (25\u201340 PSI) removes coating without substrate erosion, but the tannin residue it deposits on the aluminum surface is a more significant concern for subsequent processing than any mechanical substrate damage. For aluminum going to anodize or plating, the organic contamination from walnut shell is a more consequential issue than any surface damage risk.<\/p>\n    <\/div>\n  <\/div>\n\n  <div class=\"pm-faq-item\" itemscope itemprop=\"mainEntity\" itemtype=\"https:\/\/schema.org\/Question\">\n    <p class=\"pm-faq-q\" itemprop=\"name\">Is walnut shell safe to use indoors, and what respiratory protection is required?<\/p>\n    <div itemscope itemprop=\"acceptedAnswer\" itemtype=\"https:\/\/schema.org\/Answer\">\n      <p class=\"pm-faq-a\" itemprop=\"text\">Walnut shell blast operations require respiratory protection comparable to plastic media blasting \u2014 minimum P100 half-face respirator for cabinet work, supplied-air respirator for blast room operations. The walnut shell dust generated during blasting is classified as nuisance\/organic dust in most regulatory frameworks, but OSHA&#8217;s nuisance dust PEL (15 mg\/m\u00b3 total, 5 mg\/m\u00b3 respirable) can be approached or exceeded in poorly ventilated blast rooms during active blasting. Additionally, walnut shell contains juglone, a naturally occurring organic compound that can cause contact dermatitis and has been reported to cause sensitization in some individuals with repeated dermal exposure. Workers with nut allergies should be aware that walnut shell dust contains proteins from the walnut plant and may trigger allergic responses, though the processed, dried shell used for blasting has significantly lower allergen content than fresh nut material. Full PPE protocols \u2014 blast hood, supplied air, coveralls, gloves \u2014 are appropriate for walnut shell blast room operations, the same as for plastic media. For blast cabinet work, P100 half-face respirator and gloves are the minimum acceptable protection for walnut shell operations.<\/p>\n    <\/div>\n  <\/div>\n\n  <div class=\"pm-faq-item\" itemscope itemprop=\"mainEntity\" itemtype=\"https:\/\/schema.org\/Question\">\n    <p class=\"pm-faq-q\" itemprop=\"name\">Can I use walnut shell in the same blast cabinet I use for plastic media without contamination problems?<\/p>\n    <div itemscope itemprop=\"acceptedAnswer\" itemtype=\"https:\/\/schema.org\/Answer\">\n      <p class=\"pm-faq-a\" itemprop=\"text\">Sharing a blast cabinet between walnut shell and plastic media is possible with a complete clean-out between media types, but it introduces practical complications. Walnut shell dust and fine particles are hygroscopic (absorb moisture) and can accumulate in corners, dust collector filters, and hopper surfaces \u2014 when plastic media is subsequently loaded, moisture from residual walnut shell dust can transfer to the plastic media and cause flow irregularities. More importantly, any plastic media used after walnut shell in a cabinet without thorough cleaning will carry trace tannin contamination into the blast stream, defeating the purpose of switching to plastic media for cleanliness-critical applications. For any application where you have switched to plastic media specifically because you need a clean surface \u2014 pre-anodize, pre-plate, mold cleaning \u2014 thorough cleaning of the blast cabinet after walnut shell use is non-negotiable. Practically, for production operations requiring both media types, separate dedicated cabinets are the most reliable solution. For hobbyist or low-volume operations, a complete clean-out procedure (vacuum all interior surfaces, blow out the hopper and media delivery system, run a small purge batch of the new media before production) is an acceptable alternative.<\/p>\n    <\/div>\n  <\/div>\n\n  <div class=\"pm-faq-item\" itemscope itemprop=\"mainEntity\" itemtype=\"https:\/\/schema.org\/Question\">\n    <p class=\"pm-faq-q\" itemprop=\"name\">Why is walnut shell commonly used for firearm cleaning but plastic media is not the standard choice there?<\/p>\n    <div itemscope itemprop=\"acceptedAnswer\" itemtype=\"https:\/\/schema.org\/Answer\">\n      <p class=\"pm-faq-a\" itemprop=\"text\">Walnut shell&#8217;s dominance in firearms cleaning \u2014 specifically in rotary tumbler case cleaning for reloaders and in small-cabinet cleaning for handguns and rifle components \u2014 comes from historical precedent, supply chain accessibility, and application fit rather than from any technical superiority over plastic media. Walnut shell has been used in jewelry and firearms cleaning for decades, establishing it as the default choice in those supply chains before plastic blast media became widely available. For the specific application of cartridge case cleaning (removing carbon fouling, oxidation, and residue from brass cases), walnut shell is effective, inexpensive, and produces the dry, matte finish that reloaders prefer before sizing and priming. Plastic media at equivalent mesh sizes would also work for this application, but at 2\u20133\u00d7 the purchase price without a meaningful performance advantage for this particular use case. For more demanding firearms applications \u2014 refinishing metal components before bluing, Parkerizing, or Cerakote \u2014 plastic media&#8217;s cleaner surface preparation is actually preferred, and it is increasingly used in professional gunsmithing shops for those applications precisely because it leaves the metal cleaner for subsequent finishing processes.<\/p>\n    <\/div>\n  <\/div>\n\n  <div class=\"pm-faq-item\" itemscope itemprop=\"mainEntity\" itemtype=\"https:\/\/schema.org\/Question\">\n    <p class=\"pm-faq-q\" itemprop=\"name\">If walnut shell is cheaper and works on most surfaces, why would anyone choose plastic media for automotive restoration?<\/p>\n    <div itemscope itemprop=\"acceptedAnswer\" itemtype=\"https:\/\/schema.org\/Answer\">\n      <p class=\"pm-faq-a\" itemprop=\"text\">For hobbyist restoration of one or two vehicles per year without a reclaim system, walnut shell&#8217;s lower purchase price is a genuine advantage \u2014 the arguments for plastic media at that scale are real but less compelling. Where plastic media becomes decisively better for automotive restoration is in three scenarios. First, any vehicle with aluminum body panels, aluminum substructure, or aluminum components going to anodize or bright work \u2014 the tannin contamination risk from walnut shell makes it inappropriate for these substrates without extensive post-blast chemical cleaning. Second, high-volume operations processing multiple vehicles per week where reclaim economics matter: plastic media&#8217;s 4\u20138 reuse cycles vs. walnut shell&#8217;s 2\u20134 cycles, combined with more predictable reclaim system behavior, produce a lower total cost of ownership even though the purchase price is higher. Third, shops in humid climates or without climate-controlled media storage \u2014 walnut shell&#8217;s moisture sensitivity produces inconsistent strip rate and bridging problems that plastic media avoids. For a weekend hobbyist in a dry climate stripping a single steel-bodied vintage car and spraying rattle-can primer, walnut shell is a perfectly reasonable choice. For a professional restoration shop processing vehicles daily with subsequent coating requirements, plastic media is the correct investment.<\/p>\n    <\/div>\n  <\/div>\n\n<\/div>\n\n<hr class=\"pm-section-divider\">","protected":false},"excerpt":{"rendered":"<p>Plastic Media vs Walnut Shell: Which Is Better? Plastic blast  [&#8230;]<\/p>","protected":false},"author":1,"featured_media":12357,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[62,177,138],"tags":[],"class_list":["post-12345","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","category-material","category-resource"],"_links":{"self":[{"href":"https:\/\/hlh-js.com\/ja\/wp-json\/wp\/v2\/posts\/12345","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/hlh-js.com\/ja\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/hlh-js.com\/ja\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/hlh-js.com\/ja\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/hlh-js.com\/ja\/wp-json\/wp\/v2\/comments?post=12345"}],"version-history":[{"count":3,"href":"https:\/\/hlh-js.com\/ja\/wp-json\/wp\/v2\/posts\/12345\/revisions"}],"predecessor-version":[{"id":12382,"href":"https:\/\/hlh-js.com\/ja\/wp-json\/wp\/v2\/posts\/12345\/revisions\/12382"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/hlh-js.com\/ja\/wp-json\/wp\/v2\/media\/12357"}],"wp:attachment":[{"href":"https:\/\/hlh-js.com\/ja\/wp-json\/wp\/v2\/media?parent=12345"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/hlh-js.com\/ja\/wp-json\/wp\/v2\/categories?post=12345"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/hlh-js.com\/ja\/wp-json\/wp\/v2\/tags?post=12345"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}