Answers to the most common questions about plastic blast media, blast cleaning, and the AeroBlast process — covering grade selection, substrate safety, MIL-spec qualification, and reuse cycles.
Ask our engineersPlastic blast media is a granulated abrasive made from thermoset polymers — typically urea-formaldehyde, melamine-formaldehyde, acrylic, or Poly Allyl Diglycol Carbonate (CR-39) — engineered to clean and strip surfaces without damaging the underlying substrate. The particles are angular, lightweight, and far softer than mineral abrasives (3.0–4.0 on the Mohs scale, versus roughly 7 for silica sand and 9 for aluminum oxide), so they fracture and chip coatings without etching, warping, or embedding in the base metal.
AeroBlast manufactures four production grades — Type II, Type III, Type V, and Type VI — each formulated for a different combination of substrate hardness, contaminant, and required aggression.
Plastic media blasting (PMB) propels granulated plastic particles through a nozzle using compressed air at relatively low pressures — typically 25 to 45 psi, sometimes as low as 15 psi for delicate substrates. On impact, the angular particles fracture loose contaminants like carbonized polymer, paint, powder coat, or oxidation while the substrate is left dimensionally intact.
Properly engineered systems run a closed loop: spent media is automatically reclaimed, the dust and fines are classified out, and the usable fraction is returned to the blast pot. The result is an aggressive cleaning action with far lower per-cycle media cost than single-pass abrasives.
Plastic blast media is engineered specifically for precision and sensitive substrates. It safely cleans hardened tool steel, chrome plating, aluminum, brass, magnesium, copper alloys, thin-gauge sheet, fiberglass, carbon composites, and electronic components — all without measurable dimensional loss or surface profile change.
This makes it the default choice for cleaning injection molds, extrusion feed screws, screw tips, die heads, and breaker plates, as well as for aerospace coating removal where harder abrasives would compromise structural integrity.
Yes. Plastic media is engineered to be reused through multiple blast cycles. With a properly tuned reclamation system — one that classifies out the dust, fines, and contaminant from each cycle — granulated plastic media typically delivers many usable passes before particles break down below the working size cut-line.
Actual reuse cycles depend on blast pressure, nozzle distance, the hardness of the part being cleaned, and reclaim efficiency. Lower pressures and proper equipment can stretch media life dramatically and slash per-cycle consumable cost versus single-pass abrasives.
The two characteristics that matter most are hardness and particle shape. Silica sand sits around 7 Mohs, glass bead around 5.5, aluminum oxide around 9 — all hard enough to etch, peen, or remove parent material from precision tooling. Plastic media at 3.0–4.0 Mohs is intentionally softer than the substrate, so it strips coatings without altering geometry.
Plastic media is also chemically inert and contains no free silica, eliminating the silicosis risk associated with silica sand. Combined with multi-cycle reusability, that makes it the right choice when substrate integrity, operator safety, or finish tolerance can't be compromised.
MIL-DTL-85891C is the active U.S. Department of Defense detail specification that defines plastic media used to remove coatings from aircraft, weapons systems, and other military components. It sets requirements for chemical composition, hardness, particle size distribution, bulk density, friability, and contamination limits across the recognized media types.
AeroBlast Type II, Type III, and Type V media are qualified to MIL-DTL-85891C — authorizing their use across defense and aerospace coating-removal programs. Common qualified uses include aircraft paint stripping, landing gear stripping, aircraft wheel stripping, propeller stripping, aerospace MRO, and aircraft engine overhaul.
Type VI (Poly Allyl Diglycol Carbonate / CR-39) is engineered for medical device, surgical instrument, and precision-tooling applications rather than aerospace coating removal, and is outside the scope of MIL-DTL-85891C.
Procurement continuity: buyers whose specifications reference prior revisions in the MIL-DTL-85891 series may specify AeroBlast Type II, III, or V media as direct successors under the current MIL-DTL-85891C revision — no product substitution required.
The right grade depends on the substrate, the contaminant, and how aggressive the cleaning needs to be:
Type V (Acrylic, 3.5 Mohs) — general cleaning of injection-mold tooling and feed screws. The everyday workhorse.
Type II (Urea, 3.5 Mohs) — versatile, all-purpose cleaning for mold and screw work, plus paint and powder-coat residue removal.
Type III (Melamine, 4.0 Mohs) — the most aggressive grade in the granulated line. Built for steel and chrome molds and heavily carbonized feed screws.
Type VI (Poly Allyl Diglycol Carbonate / CR-39, 3.0 Mohs) — a premium thermoset grade engineered for critical medical device applications, surgical instruments, and implantable components. Also ideal for chrome-plated molds, feed screws, and deflashing electronic components.
Yes — and it's the method of choice for both. Plastic blast media strips carbonized polymer, char, and resin residue from injection molds, extrusion screws, twin screws, screw tips, dies, and breaker plates without altering geometry, polish, or chrome plating. It replaces wire brushing, hazardous torch work, and chemical strippers.
AeroBlast also manufactures a patented mobile clam-shell cleaning cabinet specifically for feed screws. Cycle time collapses from a full operator shift to well under an hour, with one operator, no fumes, and a dimensionally intact screw at the end of the cycle.
Yes. Plastic media is the preferred way to strip paint and coatings from composites — carbon fiber, fiberglass, and thin bonded laminates — precisely because it is soft enough to protect the substrate. The angular particles cut the coating while the low hardness (Mohs ~3.5 or softer) abrades the coating far faster than the laminate beneath, so you remove paint without cutting fibers, delaminating plies, or reducing fatigue life the way harder mineral abrasives — glass bead, garnet, aluminum oxide — do.
For composite work the softer plastic types do the job. Type V (Acrylic) is the go-to for thin skins and composites needing a wide safety margin; Type II (Urea) handles robust, well-adhered coatings at a higher strip rate. Both are current MIL-DTL-85891C types. For the most delicate fiberglass and precision work, Type VI (Poly Allyl Diglycol Carbonate / CR-39) is the gentlest grade available — it sits outside the military spec but is still produced as a specialty media. As always, confirm the specific media/substrate combination is approved for your part before running production hardware.
Yes. Type VI (Poly Allyl Diglycol Carbonate / CR-39, 3.0 Mohs) is a current AeroBlast production grade and remains fully available. It sits outside MIL-DTL-85891C by design, not by discontinuation.
The specification governs plastic media for aerospace and defense coating removal, and Type VI is engineered for a different job — it is the softest, gentlest grade in the line, formulated for medical devices, surgical instruments, chrome-plated molds, and precision tooling where preserving the surface profile matters most. Types II, III, and V carry the MIL-DTL-85891C qualification for coating-removal programs; Type VI is the specialty grade for delicate and critical work. If your application calls for the lowest-hardness option, Type VI is the one to specify.
Tell us about your application and our in-house engineers will compose a custom solution — engineered for your substrate, your tolerances, and your production environment. No obligation.