Sunday, March 5, 2017

10 Most Commonly Asked Mold Making Questions

Mold making is defined as the process of duplicating other objects through the use of molds. To make molds you can use a variety of techniques and materials. We thought we would answer some of the most frequently asked questions on mold making here as it relates to mold making, ComposiMold, and ImPRESSive Putty.

How much mold making material do I need?

If you know how many gallons or liters of ComposiMold you need: The quick answer is that you will need 11 pounds per gallon, 2.75 pounds per liter or 0.042oz. per ml.

If you don't already know the volume of material you need, you can measure water as if it were ComposiMold as seen in this video: 

Or You can do Math!

Start by figuring out the size of your part. The easiest way to estimate is to take the length, width and height dimensions as an estimate in cubic centimeters or cubic inches. To this dimension, add an inch to each dimension and find the total area of your mold (Or use the volume of your container that you will be molding the part in) Subtract the part size from the container size and multiply by the density of the ComposiMold. This will give you the amount of ComposiMold you need.

ComposiMold has a density of 1.2 grams per cubic centimeter or 0.7 ounces per cubic inch. In most cases approximately a 0.5 inch on the outside of your mold is good to provide mold support to your mold.

10 oz. ComposiMold = 14 cubic inches 
20 oz. ComposiMold = 28 cubic inches
40 oz. ComposiMold = 56 cubic inches

Here is an example:
The part to be molded is 4.5 x 6 x 0.5 inches. I suggest about a 0.5 inch of ComposiMold around to provide support. So 5.5 x 7 x 1.5 inch container. 57.75 cubic inches of material minus the original piece 4.5 x 5 x 0.5=13.5 cubic inches. So 57.75-13.5 = 44.25 cubic inches. Convert to weight. ComposiMold has a density of 1.2 g/cc (0.7 ounces per cubic inch) so: 44 times 0.7 = about 30 ounces of ComposiMold to make this mold. ComposiMold is also nice because if you decide to make the mold bigger or use too much material, you can just reuse it later, so it is not just wasted unlike most mold making materials.

For press molds like ImPRESSive Putty, you need to estimate the surface area. Typically, you want about a 1/4 inch to a half inch of mold making putty around your part. You can get a quick estimate of the surface area by placing a piece of paper around your mold. Measure that area and then multiply it by a thickness. 

And the advantage of ComposiMold and ImPRESSive Putty is you can re-use it, so you aren't wasting any material if you melted too much. 

What can I cast into the molds? Can I mold metal?
You can use many casting materials in the ComposiMold rubber molds including:

plaster or gypsumconcrete:Use as thick a mixture as possible to give stronger castings: Because ComposiMold is biodegradable, if the solution is too liquidy, you may damage the mold details.

Silicone: Use either tin cured silicone or platinum cured silicone rubber. Both work great as rubber casting materials.

plastics:look for urethane or epoxy resins that cure slowly to reduce the heat created during curing.

chocolate:works awesome: white chocolate, dark chocolate, tasty chocolate

candle wax, and soap! Freeze the ComposiMold first so that the wax or soap will cool faster than the ComposiMold can heat up.

Many others.

ImPRESSive Putty works with the same materials plus fast curing urethanes, and low melt metals. ImPRESSive Putty is not certified food contact safe like ComposiMold.

ComposiMold melts at 130 F. Any casting that creates heats up to more than 130 F can melt ComposiMold, but there are many ways to get around this limitation. Examples include:
  • Pouring in intervals so each pour only creates a little heat and the heat can dissipate
  • Adding filler such as dry talc, other dry powders, wood chips, etc. to the casting material so there is less casting material to create heat
  • Freeze or Cool the ComposiMold or ComposiMold-Firm (PowerMold) prior to pouring in the casting material. The heat during curing can sometimes be removed faster than the ComposiMold can heat up. This is a great way of doing candle wax and soaps.
  • Using a brush-on mold making material such as latex, urethane rubber, or silicone to create a barrier. This also helps create molds that can last for many more castings. This allows 90-95% of the mold to be reused whiles still getting the benefit of longer lasting molds.

How do I add colors to my casting materials?
We have special resin colorants that work really well with most resins. In epoxy, you can use a little acrylic paint and even a little food coloring as well. We also have glow in the dark colorants.

Can I make molds of body parts? Can I make body molds?

ComposiMold is a little too hot. ImPRESSive Putty will work, but is slower to cool unless you can put it in a cool environment. We have body molding powder that will work as well to duplicate body parts, but it typically can only be used once. 

Is it safe for food molds like chocolate molds?
ComposiMold is certified food contact safe. So yes, chocolate mold making is awesome. The chocolate is also re-usable, unless you eat it.

How do I make a mold?
Download our free mold making instructions e-book to learn more. We also have tons of videos. Start simple. Remember, ComposiMold is re-usable, so as you get more comfortable, you can build up to more complex molds.

What mold making material do I use?
We actually have 3 different ComposiMolds:
·         ComposiMold-Flex: for waxes, soaps, and chocolates (shore A hardness of about 3-5, soft and very flexible to make it easier to flex the casting out of the mold)
·         ComposiMold-Original: a good compromise of firmness and flexibility so you can still easily remove your parts (shore A hardness of about 10 at room temperature)
·         ComposiMold-Firm: firmest, mostly for polymer clay push molding. (shore A hardness of about 20)

We also have the ImPRESSive Putty, which is pretty firm as well.

With care, (not burning it and filtering debris from it) there is no limit to the number of times you can reuse ComposiMold or ComposiMold-Firm (PowerMold). They have been certified to conform to ASTM D-4236 for reuse more than 35 times.

We need one more question, so please let us know what questions you have, and we'll answer it. Email us at, or call 1-888-281-2674

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