Hydrocal and Ultracal 30?

[x360graphicsx]

Ok, I dont know if this is the same thing as Logan 5 just asked, however here is the deal. I have a plastiline clay sculpt that I need a mold made from it. I will be using foam latex for my final piece, however what is better to make the mold from, Hydrocal or Ultracal 30. Im using hot foam latex that needs to be baked in the over at 200 degrees. Which compound will hold up better to the heat!

thanks~

[jedideni]

It's been ages since I did any of that, but I think either will work for you.

The one thing you'll want to do is add layered strips of burlap to the mold as you build it to increase its strength and keep it from cracking and breaking apart from the heat of baking.

HTH, maybe someone with more recent experience can chime in?



Dennis

[Mostly Fantasy]

Hi!
I always preferred using ultracal 30- it's a gypsum cement instead of a plaster, so it has a better library life, in my opinion- but the previous poster is right, either will work- you could even make your mold out of molding plaster, it just won't last as long. The reinforcing tip is a good one- I use fiberglas rovings instead of burlap, as they tend to lay a little flatter and not soak up as much water out of the plaster as the burlap. Be sure to let your mold cool down (as with sculpey) before taking it out of the oven so as to avoid cracks. Also, most suppliers of foam latex sell a paste separator that really helps- you just brush it in zinc oxide, I think?

[Mostly Fantasy]

Before I forget- I was told that plaster calcifies at 200 F., so I always "cooked" my foam at about 175 with a pan of water on the bottom of the oven. At times when I baked it right at 200, the foam came out really stiff- the lower temp./slightly longer times and it came out spongy, like you'd want/expect foam to be. Hope this helps!

[2Bit Sculptor]

From what I remember, Ultracal 30 is denser than Hydrocal, so it will absorb less moisture. You will have to let it dwell just a little longer than Ultracal to skin to the thickness you desire.

Always expect the first couple pulls to be a learning experience.

http://www.theeffectslab.com/ is good place to get that info.

Chuck