Machinable Foam | McMaster-Carr

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35 Products

Prototyping Foam

The ideal material for bringing concepts to life. Rigid yet lightweight, these fine-grain urethane foams cut cleanly in all directions, with no knots to work around like with wood. They’re a popular choice for production tooling, architectural models, 3D topographical maps, and other designs where the details matter. Machine them using standard high-speed steel cutting tools or carve them by hand using common woodworking gear. The foam’s closed-cell structure absorbs no moisture and won’t deform when wet, so you can paint them, too.

Off-White—Low-density foam is easy to carve by hand but leaves powdery dust when cut. High-density foam is best suited for CNC routers and milling machines. For a polished result without chipped corners, start with a rough cut that leaves 1-3mm of material and finish with hand tools.

Light Pink—Our hardest, densest prototyping foam. It’s harder than some plastics, with greater compressive strength than sidewalk cement, but still ultra machinable and smooth to cut. Often used to craft aerospace prototypes as well as finished aircraft components, it’s ideal for lightweight designs where structural integrity is paramount.

						Tolerance
	Thk.	Wd.	Lg.	Density, lb/ft³	Hardness	Thk.	Wd.	Lg.	Softening Temp., ° F		Each
Off-White



		1"	24"	48"	6	Durometer 8D	-0.003" to 0.003"	0" to 1/4"	0" to 1/2"	245	0000000	000000


		1"	24"	48"	10	Durometer 16D	-0.003" to 0.003"	0" to 1/4"	0" to 1/2"	245	0000000	000000
		1"	24"	48"	20	Durometer 36D	-0.003" to 0.003"	0" to 1/4"	0" to 1/2"	245	0000000	000000
		2"	24"	48"	6	Durometer 8D	-0.003" to 0.003"	0" to 1/4"	0" to 1/2"	245	0000000	000000
		2"	24"	48"	10	Durometer 16D	-0.003" to 0.003"	0" to 1/4"	0" to 1/2"	245	0000000	000000
		2"	24"	48"	20	Durometer 36D	-0.006" to 0.006"	0" to 1/4"	0" to 1/2"	245	0000000	000000
		3"	24"	48"	6	Durometer 8D	-0.003" to 0.003"	0" to 1/4"	0" to 1/2"	245	0000000	000000
		3"	24"	48"	10	Durometer 16D	-0.003" to 0.003"	0" to 1/4"	0" to 1/2"	245	0000000	000000
		3"	24"	48"	20	Durometer 36D	-0.006" to 0.006"	0" to 1/4"	0" to 1/2"	245	0000000	000000
		4"	24"	48"	6	Durometer 8D	-0.003" to 0.003"	0" to 1/4"	0" to 1/2"	245	0000000	000000
		4"	24"	48"	10	Durometer 16D	-0.003" to 0.003"	0" to 1/4"	0" to 1/2"	245	0000000	000000


		4"	24"	48"	20	Durometer 36D	-0.006" to 0.006"	0" to 1/4"	0" to 1/2"	245	0000000	000000


		Light Pink



				2"	6"	12"	48	Durometer 63D	0" to 1/8"	0" to 1/4"	-1/8" to 1/8"	245	0000000	000000


				2"	12"	12"	48	Durometer 63D	0" to 1/8"	0" to 1/4"	-1/8" to 1/8"	245	00000000	000000
				2"	12"	24"	48	Durometer 63D	0" to 1/8"	0" to 1/4"	-1/8" to 1/8"	245	00000000	000000
				2"	24"	24"	48	Durometer 63D	0" to 1/8"	0" to 1/4"	-1/8" to 1/8"	245	00000000	000000
				3"	6"	12"	48	Durometer 63D	0" to 1/8"	0" to 1/4"	-1/8" to 1/8"	245	0000000	000000
				3"	12"	12"	48	Durometer 63D	0" to 1/8"	0" to 1/4"	-1/8" to 1/8"	245	00000000	000000
				3"	12"	24"	48	Durometer 63D	0" to 1/8"	0" to 1/4"	-1/8" to 1/8"	245	00000000	000000
				3"	24"	24"	48	Durometer 63D	0" to 1/8"	0" to 1/4"	-1/8" to 1/8"	245	00000000	00000000
				4"	6"	12"	48	Durometer 63D	0" to 1/8"	0" to 1/4"	-1/8" to 1/8"	245	0000000	000000
				4"	12"	12"	48	Durometer 63D	0" to 1/8"	0" to 1/4"	-1/8" to 1/8"	245	00000000	000000
				4"	12"	24"	48	Durometer 63D	0" to 1/8"	0" to 1/4"	-1/8" to 1/8"	245	00000000	000000


				4"	24"	24"	48	Durometer 63D	0" to 1/8"	0" to 1/4"	-1/8" to 1/8"	245	00000000	00000000
				6"	6"	12"	48	Durometer 63D	0" to 1/8"	0" to 1/4"	-1/8" to 1/8"	245	0000000	000000
				6"	12"	12"	48	Durometer 63D	0" to 1/8"	0" to 1/4"	-1/8" to 1/8"	245	00000000	000000
				6"	24"	24"	48	Durometer 63D	0" to 1/8"	0" to 1/4"	-1/8" to 1/8"	245	00000000	00000000

Foam Casting Compounds


Compound expands to fill every hole and cavity.	Beige

Create lightweight molds with these two-part compounds. They expand as foam after they’re poured to fill every cavity. The denser the foam, the less it will expand. Before casting, apply petroleum jelly (not included) to prevent sticking, stretching, and tearing. It won't cause the foam to collapse as it cures.

Rigid—Rigid compounds form stiff, closed-cell foam, which prevents water and air from flowing through the part. Machinable, they’re dense enough to create prototype modeling blocks, so you can test setups without wearing down tools.

	Time to Cure, min.	Time to Demold, min.	Cure Temp., ° F	Max. Temp., ° F	Shrinkage	Color	Mixing Req.	Wt., lb.		Each
Polyurethane Foam







	Rigid—Machinable

	2X	20	3	15	15	75	85	Not Rated	Beige	Yes	16	0000000	0000000


	7X	12	3	15	15	75	85	Not Rated	Beige	Yes	4	00000000	00000
	7X	12	3	15	15	75	85	Not Rated	Beige	Yes	16	0000000	000000
	19X	4	3	15	15	75	85	Not Rated	Beige	Yes	4	00000000	00000
	19X	4	3	15	15	75	85	Not Rated	Beige	Yes	16	0000000	000000

Crack-Resistant Rigid Polyimide Thermal Insulation Sheets

Even when subjected to heavy compression, these rigid polyimide sheets won't crack. To use outdoors, add metal jacketing.

60 lb/ft³ Density

Image of Product. Front orientation. Thermal Insulation Sheets. Crack-Resistant Rigid Polyimide Thermal Insulation Sheets.

Sheets with a density of 60 lb/ft³ are more durable than less dense polyimide insulation sheets, so they can stand up to machining. They’re often used for mold bases or press insulation.

	Lg.	Insulation R Value	Flexibility	Temp. Range, ° F	Heat Flow Rate @ Temp.	Color	Performance	Flammability Rating		Each
1/4" Thick



	12"	12"	0.3	Rigid	-300 to 550	0.8 BTU/hr @ 75° F	Brown	Crack Resistant	UL 94 V-0	0000000	0000000


	12"	24"	0.3	Rigid	-300 to 550	0.8 BTU/hr @ 75° F	Brown	Crack Resistant	UL 94 V-0	0000000	000000
	24"	24"	0.3	Rigid	-300 to 550	0.8 BTU/hr @ 75° F	Brown	Crack Resistant	UL 94 V-0	0000000	000000