Two materials that share a settings neighbourhood and nothing else.
Foam and rubber sit together on this page because Boss publishes them next to each other and because a shop that does one usually ends up doing the other. They have almost nothing else in common. Foam is fast, quiet, low-power work that turns into tool control and packaging; rubber is slow, dense, extremely smelly work that turns into stamp dies. What they do share is the trap in this category: two of the most common products on the shelf are named “foam board” and “rubber”, and some of each must never go in a laser.
Tool-tray and case inserts, packaging foam, gaskets, and laser-cut rubber stamp dies.
Which polymer you actually have, extraction capacity, and — on foam — how the stack is held flat.
The one thing worth knowing before anything else
“Foam board” is two completely different products and one of them is PVC. Paper-faced polystyrene foam board — craft foam board — cuts. PVC foam board, sold as Sintra, Forex, Komatex and similar, must never go in a laser: it releases hydrogen chloride, which harms the operator and corrodes the machine from the inside out. They sit on adjacent shelves in the same sign-supply catalogue, in the same thicknesses, described with the same two words. If you take one rule from this page, take that one.
A CO₂ sized to your case or tray, with extraction specified properly. Rubber is the smelliest job in the building.
Size a CO₂ System| Job | Power % at 70 W / 105 W / 155 W | Speed | Notes |
|---|---|---|---|
| Foam — cutting | 60 / 55 / 40 | 25 mm/s | Single pass at 1/4″ |
| Rubber — engraving | 30 / 20 / 15 | 350 mm/s | Stamp dies; scan gap 0.065 mm |
| Rubber — cutting | 85 / 75 / 70 | 10–15 mm/s | Single pass at 1/8″ |
Note how far the foam row sits from the rubber cutting row: foam parts at 60% and 25 mm/s, rubber needs 85% at a third of that speed. Foam is one of the easiest materials on the whole chart; rubber is one of the more demanding. Boss publishes one foam row and one rubber row, which is the honest limit — “foam” covers several polymers that behave differently, and the figures are a starting point to prove on your own stock.
Cutting foam is how shadow boards, tool-tray inserts and case foam get made — the recessed pockets that hold each tool in a fixed place so a missing one is visible at a glance. That is a real operational requirement in aerospace, maintenance and any regulated shop that has to account for its tools, and it is the sort of work a laser suits perfectly: every pocket is a drawn outline, so a new tray is a file rather than a fixture.
EVA, polyethylene and polyurethane foams — the common tool-tray and case materials. Clean, fast, low power. Closed-cell stock gives the crispest pocket walls.
Paper-faced foam board (polystyrene core). The paper faces burn and the core softens, so keep power low and speed up. Fine for models and mock-ups, less so for anything structural.
PVC foam board — Sintra, Forex, Komatex, “expanded PVC”. Releases hydrogen chloride. No setting, no extraction rig and no thickness makes it acceptable.
Two practical things about thick foam
Depth is the constraint, not power. Tool trays are often an inch or more, well beyond the 1/4″ Boss publishes for a single pass, and the honest answer is that thick foam is cut in passes or in laminated layers rather than in one heroic go. Layering is usually the better route anyway: cut several thinner sheets and stack them, which gives you stepped pockets and a far more useful tray than a single-depth cut.
Foam is light and it lifts. The same air assist that keeps the cut clean will pick up a sheet of thin foam, so hold it down at the margins or on a bed that pulls a vacuum. And the fire caution from the rest of this category applies: low-density foam runs fast at low power and does not need much encouragement to flare, so stay with the machine.
A laser-made stamp is a relief: the beam clears away everything that should not print, leaving the artwork standing proud. Three things separate a stamp that works from one that smudges:
- Mirror the artwork. A stamp prints its reverse. This is the mistake everyone makes exactly once.
- Give the relief a shoulder. Clear a wide, slightly tapered area around the artwork rather than a narrow trench. A vertical-walled letter standing alone will pick up ink on its sides and print a halo; a shouldered one will not.
- Clear enough depth. Too shallow and the background catches ink on every impression. Boss publishes 30% / 20% / 15% at 350 mm/s for engraving rubber; depth then comes from passes and from how much material you are asking it to remove.
Use rubber sold as laser-grade, and treat everything else as unknown
Laser stamp rubber is a named grade, and grades exist because the general category is not uniform. Rubber compounds vary enormously in what they are filled and vulcanised with, and an unmarked offcut tells you nothing about what it will release when you vaporise it. That is the same rule this site applies to wood-look laminate, vegan leather and foam board: if nobody can name the material, do not run it, and ask for the SDS. Laser-grade rubber also behaves consistently, which matters when a stamp has to match the one you made last month.
Budget the extraction before the machine. Rubber is the strongest-smelling common laser material, worse than leather and considerably worse than wood, and the odour is persistent in a way that surprises people the first time. This is not a comfort issue to solve later — a shop that adds stamp work to an under-specified extraction setup finds out within a day. Air assist blows the plume out of the cut; extraction takes it out of the room, and those are two different pieces of equipment.
Foam & rubber FAQs
Questions people ask about foam and rubber.
Two of these are safety questions wearing ordinary clothes.
QHow do you make a rubber stamp with a laser?
You engrave away everything that should not print, leaving the artwork standing in relief, then cut the die out. Three details decide whether it works. Mirror the artwork — a stamp prints its reverse, and this is the mistake everyone makes once. Give the relief a shoulder: clear a wide, slightly tapered area around the design rather than a narrow trench, because a letter with vertical walls standing alone picks up ink on its sides and prints a halo. And clear enough depth, or the background catches ink on every impression. Boss publishes 30% / 20% / 15% power at 350 mm/s for engraving rubber and 85% / 75% / 70% at 10–15 mm/s for cutting it at 1/8″, on the 70 / 105 / 155 W tiers; depth comes from passes on top of that. Use stock sold as laser-grade rubber, and have proper extraction running — this is the smelliest job a CO₂ laser does.
QCan you laser cut foam, and which kinds?
Yes, and foam is one of the easiest materials on Boss’s whole chart — 60% / 55% / 40% at 25 mm/s for a single pass at 1/4″. EVA, polyethylene and polyurethane foams all cut cleanly and are the usual tool-tray, case-insert and packaging materials; closed-cell stock gives the crispest pocket walls. Paper-faced foam board cuts too, with lower power, since the paper faces burn and the polystyrene core softens. PVC foam board — Sintra, Forex, Komatex, “expanded PVC” — must never go in a laser at all. Two practical notes: anything thicker than about 1/4″ is cut in passes or, better, as laminated layers that stack into stepped pockets; and thin foam is light enough that air assist will lift it, so hold the margins down.
QIs foam board safe to laser cut?
It depends which foam board, and the name is genuinely ambiguous — this is the most dangerous naming collision in the whole soft-goods category. Paper-faced foam board, the craft and model-making product with a polystyrene core, cuts acceptably at low power. PVC foam board — sold as Sintra, Forex, Komatex or simply “expanded PVC”, and the standard substrate in sign-making — must never go in a laser. It releases hydrogen chloride, which is harmful to anyone in the room and corrosive to the machine’s optics, rails and electronics from the inside out. No power setting, extraction system or thickness makes it safe. The two sit in the same catalogues in the same thicknesses under nearly the same words, which is exactly why this catches people. Ask the supplier what the core polymer is; if the answer is vague, ask for the SDS, and if that does not arrive, do not run it.
QWhat makes laser-grade rubber different from ordinary rubber?
It is a named, consistent grade, and that consistency is the point twice over. For safety: “rubber” is not one material — compounds vary enormously in what they are filled and vulcanised with, and an unmarked offcut from the workshop tells you nothing about what it will release when you vaporise it. Laser stamp rubber is sold for this purpose and specified for it. Everything else is an unknown material, and this site applies one rule to unknown materials: do not run it, and ask for the SDS. For results: a known grade behaves the same way every time, which is what lets you reproduce a stamp you made last month rather than re-deriving the settings. Boss publishes one rubber row for engraving and one for cutting, which assumes you are on predictable stock — the numbers mean much less on a mystery compound.
QCan you laser engrave silicone rubber?
Silicone is a different polymer family from the vulcanised rubber that stamp stock is made of, and it behaves differently under a CO₂ beam — so the honest answer is that Boss publishes no silicone row, and we are not going to translate the rubber figures across to it. What we can say usefully: silicone is not a chlorinated polymer, so it does not carry the hydrogen-chloride hazard that makes PVC an absolute prohibition, but “not that specific hazard” is not the same as “characterised”. Silicone products also vary widely in filler content, and food-grade, medical and industrial silicones are not interchangeable. If you need to run it, treat it as an unknown material: get the SDS from the supplier, test on scrap with extraction running properly, and expect a different surface result from what laser rubber gives you. If the job is a stamp, use stock sold for stamps.
Sources
The foam and rubber power, speed and thickness figures are transcribed from Boss’s own BL2-T83 CO₂ material settings charts (70 / 105 / 155 W tiers) — first-party Boss data. The power limits, refocus rule and air-assist requirement come from the Boss HP Series User Manual, as does the instruction never to run unidentified material. That PVC releases hydrogen chloride and must never be lasered is documented guidance rather than our inference, and it is the basis of the foam-board warning above. Boss publishes no silicone row and no separate row per foam polymer, and we have not filled either gap with an estimate. Stamp-making technique — mirroring, shouldering the relief, pass count — and laminated tray construction are settled trade practice rather than Boss specification.
Still deciding?
Tell us the tray, the case, or the stamp volume.
Foam asks very little of a laser and rubber asks a great deal of your extraction. A specialist will size the bed to the largest insert you want to cut in one piece — and be straight about the filtration that stamp work actually needs.