Tips for Different Casting Materials

Posted by ComposiMold on 5th Nov 2018

Tips for Different Casting Materials

What are you casting with? Here we go through the basic best practices for casting in ComposiMold molds with a variety of casting materials. We have a lot of other videos, so I tried to select one or two video tutorials as an example for each. Let me know what other casting material you are interested in.

EPOXIES: Epoxy Resins, Epoxy Putty, or Epoxy Clay
The best tip is to use ComposiMold Epoxy Resin (of course :) ). ComposiCast resins are very forgiving because you can be off by 10% or more and still get great plastic castings. We are finding that some of the very cheap epoxies are leaving a whitish surface, I believe because of the diluent added to reduce the cost. This is also why those resins don’t harden well sometimes if there is more humidity. This isn’t an issue if you are adding colorants. Use ComposiCast White or Black, or use ComposiCast Clear with different colorants when using the epoxy in ImPRESSive Putty. For larger castings of 8+ cubic inches, choose epoxies with longer cure times of 24+ hours. Experiment with freezing the mold prior to pouring epoxy resins that create a lot of heat during curing. Epoxy resins that require an added heat source for curing are not recommended.
Resin casting tutorial:
Astroboy Action Figure Casting:

For fast cure urethanes, use ImPRESSive Putty because it can handle higher temperatures. Choose a urethane with a longer cure time. These create less heat as they cure. You can also experiment with freezing the mold prior to pouring higher temperature urethane resins, adding fillers, or pouring in intervals. Be sure to use talc powder/baby powder as your mold release before each casting made. Urethanes dislike moisture so the talcum powder makes a nice moisture barrier.
Plastic Duck:

ComposiMold’s Plaster of Paris or add the Plaster Additive to give harder, stronger plasters in ComposiMold molds. Mix plaster and water together in a 72 parts plaster to 28 parts water, by weight, or to a toothpaste-like consistency. The thicker the better for stronger molds. Use ComposiMold Plaster Additive in traditional plasters for strong, hard plaster. Fast curing masonry cements work great and cure extremely strong. Follow instructions for mixing ratios. And we also have the ComposiStone for hard plasters.
Plaster Casting of Tiles:
Plaster Casting of Duck Decoy:
Big dog in Concrete:

Silicones work great in ComposiMold mold or ImPRESSive Putty molds. Make castings with both platinum and tin cured silicone rubbers.
Soft Bait Fishing Lure Rubber:
Chill the mold prior to pouring any higher temperature soaps (above 140ºF). Shea Butter and Glycerine Soap make great soaps! For higher temperatures, use ImPRESSive Putty.
Bath bomb:

WAXES: (for candle molds or encaustic casting)
Soy, Paraffin, Beeswax, and Melted Crayons work really well. Chill the mold first for higher temperature waxes (above 140ºF). For higher temperatures, use ImPRESSive Putty, it works awesome (oh wait I said that above too).

CLAYS, Polymer Clays, Metal Clays, Real Clay, Modelling Compounds, etc.
Use any type of polymer clay, modeling clay, putty, or real clay for push molding in a ComposiMold. Do not use clay in a slurry form or the water will degrade the mold.
Polymer Clay:
Clay Push Mold of a leaf:

The plastic that is heated in hot water can be molded and formed using ImPRESSive Putty just like a push mold. Push it in, let it cool.
Push Mold of Heat Formable Plastic:

Pour or pipe many types of melted chocolate into your mold. Lightly tap or vibrate the mold to release air bubbles in the chocolate. No mold release is necessary for chocolates.
LARGE Chocolate:

Butter fills funny as it doesn’t press back on you. Use soft butter and press it into your mold. Place it in the refrigerator to chill and harden.
Butter Buddha:

Press softened fondant into your mold with your hands or a rolling pin and remove immediately. No mold release is necessary for fondant.
Fondant press mold:

ISOMALT or Sugar Candies
The Food Safe ImPRESSive Putty can withstand the heat for smaller candies. Several stores in Colorado have enjoyed making special candies this way. Larger molds, above about 3 cubic inches may have heat damage. Pour water in the mold and then wipe clean before making your mold to remove the activator from the surface of the mold.
Small Candies:

Papier Mache:
Work by building up in layers and letting the layers dry before moving on. You can make some beautiful castings with just paper and glue.
Papier Mache:

Freeze your mold before pouring in cold water. Put back in the freezer to freeze the water. Chillingly good results.
Ice baby, ice:

Use a no-rise cookie recipe, so leave out the Baking Soda. Press the cookie dough into the mold, pull it out, and cook it.

Make your own Gummi recipe, or Jell-O with ¼ of the water as they suggest. Use vegetable oil as a mold release. Make sure to get everywhere with the release or it will stick. Let the Gummi liquid cool to room temperature before pouring into your mold.
Venus Di Milo Gummi (Doh!)
LEGO Gummies:

You can use low melt metals, like our Wood’s Metal, in the ImPRESSive Putty. You can also use ComposiMold and ImPRESSive Putty for the lost wax process: Make a wax casting of your object, make a plaster mold of that wax object, burn it out, and then pour in your molten metal (easy! Right? Okay, this is pretty advanced).
Lost wax process:
Low Melt Metal:

You can also try adding fillers and dyes to casting materials, using ComposiMold as a rubber casting material, Modeling Compounds, Polyester Resin, Paper Mache and many more! You may also like our Re-usable Molding Putty, ImPRESSive Putty.

Do you have anything that you would like to share with the others related to ComposiMold products? I know some of you have made some really awesome things. If you send me an email, I will do my best to get them into upcoming newsletters.

Thank you!
Stan from ComposiMold

Stan Farrell
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