Need some help with casting

I’ve been embedding a few things and casting them in polyester resin, but it isn’t as clear as some lucite embedments that I have bought.

Question: Is it possible to get lucite in some form that I can embed objects within it? I know I can buy rods of acrylic and stuff, but can I melt them down and use them in some kind of liquid state?

Or is there a chemical compound that I can buy in order to form custom lucite casts? Any help would be greatly appreciated!

I think your best bet is to stick with the polyester resin. Trying to melt acrylic takes a whole lot of heat, will probably produce a lot of bubbling, and is tough to control if you don’t have the right tools. Make sure that you are using the polyester resin that is intended for casting, not for fiberglass laminating.

Yeah, make sure you’re getting “water clear” resin. Also make sure it’s not getting so hot during curing that it starts to yellow. The other thing that can make it seem less clear is surface finish- you may have to polish the finished product.

polymethyl methacrylate is the name of the material commonly known as Lucite (brand)

you can order custom shapes for corporate awards and such, cast from lucite. in a pinch. maybe you could order something from a company that makes such things.

First things first. “Lucite” type casting materials are “thermosets” and will deform when heated, but they will not melt after initial casting; they burn.

“Polyester Resin” generally found at the hardware store (for example) is for laminating with matt or cloth. If you cast it into a thick section (thicker than say, 1/8 inch [3.5mm] it will “exothermo” so rapidly that it will discolor, probably crack, and/or possibly burst into flames. With any “polyester resin” always remember to set any excess material on a fire-proof surface (like a concrete floor). If the cup starts to smoke take it out side and, again, place on fire-proof surface.

Provide plenty of ventilation, wear latex or nitrile gloves, and an ‘organics’ filtered respirator (bare skin and that flimsy paper particle mask won’t do a thing to protect your central nervous system).

See the following for casting materials (and a lot of other useful stuff):

The other thing that can make it seem less clear is surface finish- you may have to polish the finished product.

The shrink-rate for these materials is fairly high. If you are experiencing a “crackle” finish on the exterior of parts, cast into a mold, it is more than likely the incompletely catalyzed resin (closest to the mold surface) that is sticking to the mold and then being redeposited on the surface of the part as the part is removed. The main mass of the part starts to catalyze and the the part starts to shrink immediately. By the time the cross-linking reaches the surface of the mold, the part has already shrunk away from the surface (even using ‘casting’ resins).

There’s no way around it really; it’s a pain in the ass … and is common with “polyester” resins.

Epoxies, and urethanes, have a much slower rates of shrink and the problem is not so pronounced.

But then, you didn’t ask about them… :wink: