USG Hydrocal White Gypsum Cement 10 lbs - Molding and Casting Both Hollow and Solid

I used this Hydrocal to cast a stone mold and, in turn, cast 11 identical items in liquid latex. This was for a movie I worked on and I had no use for keeping this mold over the long haul. Once I was done, I broke it and tossed it. Hydrocal is biodegradable.If you're new to this and want a long-lasting mold that can handle plenty of repeated use (I'm talking years), definitely go with Ultracal.Hydrocal is great as a mold device for making a short-run number of items. Unlike Paster of Paris, there's virtually no expansion or shrink. This is why Dental Labs prefer it as part of the process for making teeth.Or, in the case of Primary mold for casting secondary liquid latex rubber molds, you can paint or slush-cast in the Hydrocal stone mold for a set of the long-term rubber mold items then toss the stone Hydrocal out.Hydrocal is also great for building scenic backgrounds for model making. Outstanding in fact, when compared to Plaster of Paris.When properly mixed, Hydrocal will be watery soupy for about the first 10 to 15 minutes (depending upon arid or humid climate). After that, it will rapidly go from a yogurt consistency, thickening to a pudding consistency, then into a thick-type mud, and finally a hard but brittle stone.Allow it to set/dry overnight into a harder, more resilient stone (way less brittle than Plaster of Paris), and you're good to go. Hydrocal Gypsum is not as hard as Ultracal, making it preferable for detail carving into the shapes you want.In humid climates such as Florida or Texas, fungal mold can grow in your Hydrocal stone if left untreated. If you choose to leave it unpainted, a light once over, periodically, with any aerosol anti-mold or fungus wet spray will be fine. Once mold does set in, that's pretty much it for your Hydrocal stone, as the exposed surface will get flaky.So if you are new to Hydrocal, build it, spray it with the antifungal, and then paint it (if you like).Finally, remember that as part of the curing process, Hydrocal gets hot enough to burn and damage skin, so never attempt to use it to cast yourself or others.Also, while mixing, make sure that you are in a well-ventilated area. This stuff is dusty! As extra protection, I always wear a decent airmask to prevent inhaling it. Not everybody does this, but Hydrocal forms a chemical reaction with liquid so I don't need it in my lungs.Hyrdocal is easy to mix, easy to cast, easy to carve, and, depending on what you want it for, can last a lifetime.If all of this sounds like exactly what you want, I don't think you'll find a better Hydrocal product than USG.

5 star all the way, Hydrocal works just as it should. Wear gloves, your skin will thank you.

It’s plaster. It arrived quickly and worked fine. I used it to make molds for slip casting porcelain

Definitely worth it

This is my fourth time purchasing this gypsum. It is the best of the best! The quality is incredible. I’ve purchased from other places and sellers in the past and will never again. This is the only seller I’ll ever buy from. Others are an inferior product by far!

Really fast dry product. Perfect for my mini gardens small business

Works great, great value

Easy to mix and easy to pour. Sets up fairly quickly