Quote Originally Posted by bford903 View Post
With FTX Cast, you have to cure, and cure, and cure, and then cure some more. It will turn from a light-green shade to white with a hint of pink. Sometimes I would have to run 6-10 cycles in the cure chamber. Larger pieces are hit-or-miss but smaller pieces cast better after extended curing. I think the reason is FTX Green is relatively transparent so the piece cures inside and out, while the FTX Cast is more opaque leaving uncured resin inside the piece. Don't know, but that's my theory.

When you mix the Plasticast, make it as thick as possible. Not too thick where it sets early or won't pour, but as thick as you can make it. This will increase the strength.

I tried using air duster to blow out the ash residue before casting, but you need to make a separate sprue for the ash residue to escape or it just blows around in there. It helped with the bad surfaces a little, but I was nervous about blowing cold air on a hot mold. Plus, an escape-hole sprue requires extra metal which costs money.

I've gone back to using FTX Green and making rubber molds from the prints.
A little bit late but thank you for the reply. About the cartridge tearing problem. With Cast cartridges they are indeed of an awfull quality but I used workaround. I end up moving the material to an empty cartridge of Green one which was much sturdier and end up getting normal prints. Also placing the thickest supports do the trick. Do not use thin supports with this material. I always end up with a half printed piece in the cartridge fallen off from the print plate if I used thin ones.

Well the all idea is not to use additional phases like rubber molding. In that case why do I need printer for? I can get the form in wax from designer and just do regular casting than. No point.

The posphate based investment seems to do the trick but it is very difficult to divest. I do it with screwdriver and hammer but.... comeon! should I pay for divesting machine because their recommended investment do not work?

I tried the recommended schedule for Plasticat - faled with the surface quality. I tried to extend the time twice - no results. I am getting rough surface. Seems that the material have some kind of temperature barier after which it starts getting an explosive boilup and that ruins the inner surface of the curing investment.

Also I noted that the lesser water in the Plasticast mix is better. I used 35/100 ratio first and it was better than 38/100 ratio I used the other time.

Now I am a bit into deadend. My friend recommends doing 14 hour burnout scheme but I doubt that it will help.

Any ideas on the chemical composition of the materials? this may help getting the correct temperature ladder which may help avoiding that explosive burnout which supposidly ruins the inner surface.