Materials Resources / Boston-centric
Kelly Heaton, 1999-2001

Acrylic (lasercutting, machining):

Commercial Plastic / Mr. Plastic:
352 McGraff Hwy in Sommerville (MA). Stock acrylic for use on a laser cutter. Other plastics include lexan for machining and thermoforming materials. Mr. Plastic also stocks glues, sratch remover etc.. for acrylics.
J. Freeman (Dorchester). Only sells 4 x 8 foot sheets, but has the best selection in the Boston area.
McMaster Carr is good for small sizes of sheet plastics, among many other things.
Solter Plastics, Inc. (310) 473-5115; (310)-478-5228. Located in Los Angeles, this place has an enormous selection of plexiglass colors (request a sample box for ~$30). Also makes custom colors.
Industrial Plastic Supply: 212-226-2010; 309 Canal Street NYC
Canal Plastics Center:
212-925-1032; 345 Canal Street, NYC

Sheet plastics (thermoforming):

Mayfield Plastics:
Phone: 508-754-3476. Contact: Ron Gaulin. HDPE: Heat the sheet plastic in an 800-900 degree F oven for approx 70 seconds. This time will vary from oven to oven, and depends upon the material thickness. .060 thickness works best, but .030 will also form well if you heat it properly. The plastic should be removed from the oven at the precise moment that it becomes clear - no longer! The melting temperature of HDPE is 325 degree F. If the material begins to sag, buckle or bubble, it will not form well. Evidence of stretching may indicate that the material has been overheated; if the material does not pull neatly into place during vacuum forming then it is likely too cool. It is far preferable to heat the material quickly in a hot oven than slowly in a cooler environment. For best results, make sure that the mold is warm prior to forming (i.e. 130 degrees F) - this can be achieved with a blow torch, or by forming several sheets of .060 HDPE and allowing them to cool on the mold. Be aware that HDPE will shrink considerably when it cools, and can stick to some molds, especially if the mold is textured. An alternate material to HDPE that thermoforms easily is PETG.
Patriot Plastics: 16 Fowle Street in Woburn, MA. Phone:
781-935-3990. They carry sheet HDPE and LDPE in .020, .030 and .060 inch thicknesses.


Boulter Plywood (Sommerville): 1/8" Okume is especially good for bending and laser-cuts well.

Rubber stock:

Greene Rubber: Phone: 781-937-9909. Carry stock rubber tubing, o-rings, sheet rubber, etc...
O-rings: American Seal, Inc.
Contact: Jody. phone: 713-675-7325. Purchase orders or COD only.

Casting resin:

; contact: Robert Hale; phone: 781-826-8801; purchase orders or COD only
- amber colored polyurethane: Hapflex 666. Works great with the Pearl-Ex dry pigments, but yellows with time and exposure to UV.
- white resin: Ultraloy 50 - dries to a hard, mostly opaque white (tint with Hapco white for a pure, opaque white).

Hapco also carries both opaque and transparent dyes for tinting casted resins and rubbers (see "pigments for tinting polyurethane," below).
Polytek Development Corporation
offers a variety of resins and rubbers, plus a useful catalogue full of samples (cost: $10).


System 3 epoxy, glass microspheres, thixotopic powder, etc: Merton's Fiberglass Supply, 413-736-0348 (Joe Merton. See also Walter Black -- for custom body work. (413) 543-1857). System 3 epoxy manual is an excellent guide to boatbuilding technique (avail. for purchase thru Merton's.)
Stone Auto Body Supply:
Rich Carlson, Manager. One of several suppliers for the auto body industry in Cambridge area.

Casting rubber:

polyurethane rubber ( see mold-making materials) is easier to work with in terms of curing time and air bubble removal, but the color is a translucent brown (= coloring options are limited).
Hapflex 766:
This polyurethane resin cures to a hard , colorless rubber. (65A durometer). The gel time is 10 minutes, so air bubbles must be removed quickly using a vacuum chamber. The rubber does not fully cure for nearly a week, although the curing process may be accelerated by heating - an 80 degree C oven for four hours was recommended by the manufacturer (but be careful to avoid heating at a higher temp, b/c the material will burn).
Clear silicone rubber (medical grade): avail. through
Applied Silicone Corp: Phone: 805-653-5638
Rubber specs:
5000062 liquid silicone, durometer: 25, 30 or 40. The mixture I tested was 10:1 (part A to part B); price: $12.60 per gallon.
This mixture takes several days to cure. Air bubble removal can be a real pain unless you have a high-powered vacuum or have the time to leave it under vacuum for awhile. The longer curing silicone would probably be fine if vacuumed for an hour or so (it's super-viscous and full of bubbles when you first mix it).
See also
(under casting resin): Polytek Development Corporation:

Mold-making materials:

(they won't sell direct; Boston-area distributor is Waldo Brothers: 445-3000.) Smooth-On (grey) silicone mold-making material: avail. at Pearl Paint. Easy to pour (low air bubbles) but rigid and succeptible to cracking. Mold lifetime: approx. 10 castings. Smooth-On polyurethane rubber for casting is also good, but needs a release agent (Smooth-On Universal Mold Release). Polyurethane rubbers are also stiffer and more succeptible to tearing than silicone. The most flexible of the Smooth-On silicones (used in the colored-light objects) is Smooth-Sil 912. Air bubbles are a problem - use a vacuum chamber prior to pouring. In general, I found that a two part mold made from half silicone and half polyurethane worked well- the silicone is good for parts which require significant flexibility during demolding, and the urethane makes a good, firm counterpart.
See also (under casting resin):
Polytek Development Corporation:

Pigments for tinting polyurethane resin (and some rubbers*):

Note: Adding pigment at or below 3-4% of total mixing weight does not require alteration of resin proportions (A to B); however, any additonal pigment will require adjument of the proportions - consult the manufacturer.

(781-826-8801): carries a variety of non-flourescent colors in both transparent and opaque dyes.
Pearl-Ex powder pigments
(non-toxic, non-conducting).
Avail. at Pearl Paint (Cambridge): 547-6600; or NYC: 212-431-7932
Also avail. by calling: 800-442-0455, or 707-433-9577 (this is their distributor; ask for a color chart)
Pearl-Ex powders work great in Hapflex 666 (polyurethane resin), but not so great in urethane rubbers - it gets sticky.
Plasticolor: pigments (esp. flourescent) for dying resin and other chemicals
Plasticolor phone:
Day-Glo Color Corporation:
specializes in flourescent yellow dyes and pigments.
BASF Corporation:
huge chemical supplier; good for intense pigments.
* Be careful to test colorants in a small sample first, as certain materials take pigments better than others. Too much pigment will cause the material to cure improperly.

Apex Resources Inc:
Distributor of mica powders. Contact: Vinita Gupta; e-mail:;
Phone: 502-326-3118

Metal Powders:

Atlantic Equipment Engineers:
United States Bronze Powders, Inc.
: Brass, nickel silver, bronze and copper powders for use in cold casting.
Phone: 908-782-5454

For conductive silver powder:
see also, Progressive Fillers International, Incorporated (Micaclad conductive silver)

Oil Paint:

Hand-made paints are avail. through Pearl Paint in NYC (212-431-7932),
or direct (phone #?).

General Arts and Crafts:

MassArt: 232-1555 / store: 739-4770
School of the Museum of Fine Arts:
Utrecht Arts and Crafts:
Pearl Paint (Cambridge)
: 547-6600
Waldo Brothers (Boston distributor for Smooth-on products):
445-3000; contact: Gary Cook
Mr. Plastic (Sommerville)
(see sheet plastic / rubber)
Altech Plastic
(South Boston - they also have full machining capabilities)
Pearl Paint (NYC):