Anyone familiar with ultra cal? help me save my sculpture!

[blkeclipse]

Ive been working on a chucky replica..just when im nearly finished making the last pieces I run into an issue. Im using ultra Cal 30 a gypsum cement. I've never had an issue with the other casts but for some reason it will not set. If I run my nail across it - it leaves a mark. Usually it sets in about 30 min. Mines been sitting over night. Would it be a bad idea to place it in the oven? Do I let it dry naturally or is there no saving this?

 

[Ozymandius]

My guess is that you mixed in too much water and/or it's been raining there. Either way you just have to wait for the excess moisture to evaporate out.

Putting it in the oven with the door open should help speed it up and there's no reason that it would hurt the plaster.

 

[blkeclipse]

Thanks. I'll give thst a try. Youre right, I think I put too much water in it. Its a 2 piece mold. The first pc set perfectly just not the second

 

[blkeclipse]

...and yes its cold and rainy here too

 

[TripdWyr]

How do you normally measure out your cement? Do you weigh it, or sift it?

 

[Bruce Miller]

You never add water to your plaster. You always add plaster to water. Start with a clean bowl, fill one third with room temp water, sift handfuls of your plaster through your fingers spreading it around on top of the water and watch it sink. Keep sprinkling it in until the powder floats on top of the water. Continue a little more until you see a dry layer on top. Stop and watch the powder turn a darker color as the water soaks up into it. Now it's time to mix and stir your batch with your hand for about a minute until it feels lump free. It'll be sorta like a thick milkshake. Now you can spread it onto your sculpture. You can use a soft brush to help get into the details and eliminate air pockets. As some runs down off the sides scoop it up and back onto yur piece. As you work with it you will notice it thickening. Try to achieve an even coat all over then stop and don't disturb it until it hardens but is still very damp then you can apply a second coat. If you wait TOO long and a coating gets too dry then the next coat may not stick to the previous as well as it should so you need to spray water onto dry coat before applying next layer. Build up several layers for a strong mold. Some people apply sisal fiber (rope fibers) or burlap or fiberglass into the outer layers for strength. The whole thing will get very warm as it sets. After it cools down it should be rock hard and ready to remove/demold.

 

[blkeclipse]

Ozy you were spot on. I saved the cast! I have the latex sitting in it now. About 25% of the thumb was lost but I, ll figure something out. The sculpt was of a hand. Thank you and thanks all for input.