Laguna ULTRACAL 30 Gypsum Cement - Plaster - for Mold Making and Casting, Ideal for Latex Molds! Takes Excellent Detail (10 lb)

It’s a very good product. This is my go to when making my molds. It do catch all the details and sets up pretty quickly. I highly recommend.

Very good for mold casting. Very fine consistency. Great overall! $$

This is nice stuff! The instructions make it sound difficult to use with all the weighing and measuring, but it isn't that complicated. I didn't weigh I just measured -- one part water, 3 parts Hydrocal 30. My piece turned out great. Watch the video about how to use it though. You need to let it sit in the water for a bit and then stir it long enough to get all the lumps out. I didn't do this and my piece still turned out good, but you can see lumps in the Hydrocal 30 on the back. Bubbles, there were a few but I wasnt careful about pouring it. The first time I use a product, I see how picky it is and am not very careful, just yo see how it turns out. Also, I used an intricate mold and didn't ensure the liquid flowed into every crack. My fault. Next time I will be more careful. The cement cures hard in about 15 minutes so you have a bit of time to mix and pour before it starts to harden. I kept it in the mold for a few hours before taking it out. It popped out of the mold easily without using mold release (silicon mold -- DON'T use it in a metal mold!) And was fully cured in about 24 hours. It has a nice feel to it. I can't speak to durability because I didn't want to try to break it, because I assume that, just like anything else made of glass or ceramic, you wouldn't drop or abuse it because it will break. The last point is the product description calls it "white." It is more like a VERY light gray. I would not call it white. The powder is white but when you mix it with water, if you want white you will have a heart attack because with water it turns very gray. It lightens up a lot when fully cured.cures. The pictures show the difference. The light gray is the Hydrocal 30. The white is from another product just to give a comparison.

this product was recommended by happydottingco.com to use with their silicone casting molds. it is perfect, bubble free finish, extremely smooth and easy to use for a first time caster.

I make molded rocks for rock painting. Mixing this is easy and if it gets spilled while filling molds or stirring mixture, it is very easy to remove. I've had 2 problems. One is that the rock needs to be sealed before painting. It absorbs the paint quickly and is not easy to remove if an error is made. In fact the moisture softens the rock so much that it leaves divots in the surface when removing. Secondly, I've noticed that even after painting possibly several coats of paint, the rock still chips if the outside edge isn't deep enough. I try to cure my rocks for several days before painting them, but the problems still occur.