If I have something in resin I would like to make revisions to, how would I go about making a mold that clay could be pushed into, so that I can make changes in the sculpt? Thanks!
how to make a CLAY casting?
- Thread starter Hecubus114
- Start date
resin and plaster wont bond together will they?
darthchiro
Well-Known Member
IT has to be a rubber mold to do a pour in, silicone is best, but you can use latex or urethane as well.
Use a mold release on the resin part, then the hydrostone won't stick to it. I've done this before for basically the same reason, the part wasn't resin it was wood, I just put a light coating of vaseline on it before I poured the hydrostone mold.
IndyFanChuck
Sr Member
Have you asked Reevz about this? Shawn is really really good at things like this....
Mold the resin piece in silicone.
Heat some clay (i would suggest something like chavant nsp medium) Try to heat the clay slowly and evenly..so something like a crock pot would be better than a microwave or toaster oven.
When the clay is molten, stir it (some slight separation sometimes occurs)
Slightly warm the mold to something like 180-240 degrees to prevent lap lines. If it is a small mold you could use a hair dryer, if it is larger use an oven.
then just pour the liquid clay in the mold and let it cool naturally (don't put it in a refrigerator anything for the first few hours)
If it is something large like a human sized bust or something, you can constantly warm the mold with a hair dryer, have a bunch of clay in a crock pot ready and brush it into the mold. Then after you have a good thickness to work with you can back it with hydrocal, plaster, polyfoam etc.
Heat some clay (i would suggest something like chavant nsp medium) Try to heat the clay slowly and evenly..so something like a crock pot would be better than a microwave or toaster oven.
When the clay is molten, stir it (some slight separation sometimes occurs)
Slightly warm the mold to something like 180-240 degrees to prevent lap lines. If it is a small mold you could use a hair dryer, if it is larger use an oven.
then just pour the liquid clay in the mold and let it cool naturally (don't put it in a refrigerator anything for the first few hours)
If it is something large like a human sized bust or something, you can constantly warm the mold with a hair dryer, have a bunch of clay in a crock pot ready and brush it into the mold. Then after you have a good thickness to work with you can back it with hydrocal, plaster, polyfoam etc.
clayslinger
Well-Known Member
We did this a lot at a shop I worked at.
Use a double boiler so you don't burn the clay with direct heat.
Heat the RUBBER mold as stated before.
As Fettster mentioned be very careful. It's a burn you won't forget!!!
Chavant NSP and Leisure Clay are noted for melting well for casting. Roma has gotten softer over the years and has been used for this as well. Back in the day we mixed Roma and Leisure clays together for a better pour.
Good luck on your project!
Chuck...
Use a double boiler so you don't burn the clay with direct heat.
Heat the RUBBER mold as stated before.
As Fettster mentioned be very careful. It's a burn you won't forget!!!
Chavant NSP and Leisure Clay are noted for melting well for casting. Roma has gotten softer over the years and has been used for this as well. Back in the day we mixed Roma and Leisure clays together for a better pour.
Good luck on your project!
Chuck...
bumping this with a follow up question:
If I am going to use the crock pot/melting method, but only have a urethane mold, should I still heat it? How hot can it get before it will get ruined?
If I am going to use the crock pot/melting method, but only have a urethane mold, should I still heat it? How hot can it get before it will get ruined?
It doesn't need to be silicone, I used alginate for a quick job and it came out quite well. If you need alginate just be sure that it's completely dry and warmed up with a hairdryer or something so you don't get frostlines in the cast.
Although alginate works fine i won't recommend it for a technical model, greeblies or something. For small scale work silicone works best.
For large scale (without major undercuts) go with alginate. Much cheaper.
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