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  • ComposiStone Hard Plaster 6 pounds
  • ComposiStone used to duplicate a garden gnome.
  • Hard Plaster Cement Casting
  • Hard Plaster Cement Casting
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  • ComposiStone casting of a wood carving used to make a mold
  • Hard Plaster Cement Casting

ComposiStone 3/4 Pounds or 6 Pounds

Usually Ships within 24 hours

Product Description

Harder than plaster yet still smoother than cement.

The texture is similar to a cement feel, but much smoother in appearance. Composi-Stone is ideal for lawn and shelf ornaments, sculptures, craft parts, and other general applications.This plaster/cement system uses a Dry mix and water at a ratio of 2.5 parts powder to 1 part water by volume. It solidifies to a beautiful light Gray color. 

Shelf Life and Storage: Composi-Stone should be stored at room temperature in a dry location. Containers must be tightly closed as a protection from moisture and foreign material.

Directions for Use:

Mold Preparation:

When using the Composi-Stone Mix in a ComposiMold, make sure the ComposiMold is completely cooled to room temperature or lower prior to use. Use a mold release that works with plaster or cement (ComposiMold's Vegetable-Oil Mold Release works great).


Measure between 2-2.5 parts dry mix to 1 part water, by volume, into a mixing container such as a plastic cup or bucket. For better accuracy, the components can be weighed. The mixing ratio, by weight, is 2 parts mix to 1 part water. Start mixing immediately and be sure to scrape the material off the sides of the mixing container. Mix until all parts are mixed up and there are little to no lumps.


After thorough mixing, pour the mix into the ComposiMold mold cavity. Using a ratio of 2:1 by volume will result in an easier pour, but a longer cure time.  The ComposiStone will begin to cure and solidify within 5 to 10 minutes depending on the temperature and the amount of water that was used. Wait approximately 3-4 hours before removing the part from the ComposiMold mold. Less time may deform the part. 


To improve clean up after using the Composi-Stone Mix, rub some Vegetable-Oil Mold Release on the mold. Tools and equipment should be scraped clean prior to the mix curing and hardening.


Safety:The powder may cause eye, skin, dermal, and respiratory sensitization. Avoid contact with skin and eyes. Use in a well ventilated area or wear a dust mask while mixing. If skin contact occurs, remove with soap and water. In case of eye contact, flush with water for 15 minutes and seek physician support. 


ComposiStone Hard Plaster 02:30

ComposiStone Hard Plaster is smoother than concrete, but harder than regular plaster of paris. It’s simple to use and picks up nice details. First, to make the mold with ComposiMold, melt your ComposiMold in the microwave or double boiler and pour over your part.if your part floats, be sure to hot glue or use double sided tape to hold your object down. Let the ComposiMold cool to solidify and then remove your object from your mold container. In this case we cut the plastic container away. If necessary, cut a slice down the back of your mold to enable easier removal of your object. Use a knife of scissors to cut. ComposiStone is mixed at about 2 to 2 1/2 parts ComposiStone to 1 part water. As you can see here, it doesn’t have to be that accurate. Too much water will make the part soft, but too little water will make the part harden very quickly. If it’s hardening too fast to get into your mold, next time use a little more water. The consistency should be like a thick pancake mix, or maybe a sour cream. In this case, a little more ComposiStone is added. Pour the ComposiStone into the mold. Shaking the container lets it flow easier. Shake the mold, vibrate, and tap it to ensure that all the areas are filled with ComposiStone. Let it solidify. It will begin to get hard within about 5 to 10 minutes, but allow it to cure for 10 or more hours before removal. Admire your piece. You can make another, or re-melt an-use your mold. To clean your mold, wipe your mold with a cold wet wash cloth. Do not put under hot water. And have fun making your ideas real. Please share this video, comment below, and subscribe to our channel for more ideas and tutorials. Thank you

  • ComposiStone H...
    ComposiStone Hard Plaster is smoother than concrete, but harde...

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Why ComposiMold for Mold Making? Because it works