Frequently Asked Questions about Mold Making with ComposiMold


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See our ImPRESSive Putty (ReMold Putty) FAQ here: ImPRESSive Putty FAQ

IT LOOKS LIKE HONEY It certainly does, but donít spread it on your toast. It definitely doesnít taste as good as honey, but it is food contact safe with no added colorants, no petroleum, and no dangerous chemicals. ComposiMold and ComposiMold-Firm (PowerMold) are safe for you and the environment. It's 100% biodegradable and re-usable. The transparency also helps you to see through the mold while making it and your castings.

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.

From a lot to a few, depending on the casting material and complexity of the mold. For chocolates, count on the mold lasting for many, many castings. For plastic or concrete, count on fewer molds. The nice part about ComposiMold products is that if the mold starts to degrade, just re-melt and re-make it!

How do I figure out how much ComposiMold rubber mold making compound I need?

If you know how many gallons or liters 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: How To Figure Out How Much Mold Making Material Is Needed Using Water

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 from one interested customer:

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.

What is the easiest and safest method to melt ComposiMold?
The easiest way is to melt the rubber molds is in the microwave. Melt the ComposiMold by heating above 130 F. Microwave times will vary depending on the microwave used.

ComposiMold flexible mold making material in the microwave

Microwave times will vary. Start melting the flexible rubber mold with short heating times until you understand how the microwave will heat the ComposiMold.

10 oz. 30-120 seconds
20 oz. 3 to 5 minutes, stir every minute
40 oz. 7 to 10 minutes, stir every minute

Warning: The ComposiMold container WILL melt if overheated. Do not heat the container without the ComposiMold in it. Also, the ComposiMold WILL BE HOT. Be careful.

You can also use a double boiler to melt your ComposiMold. A double boiler consists of one container inside another container with water between them. The purpose of the double boiler is to keep the heat from getting above 212 F. Marbles or rocks work well to keep the ComposiMold container off of the bottom of the pot. If the ComposiMold container is on a stove top directly, the container will melt. Heat the resin until it is melted.

How does ComposiMold solidify? How long does it take?
ComposiMold solidifies when it cools to a flexible, rubbery, polymer. So to solidify, just let the part cool. To speed up to process, you can put your part in the refrigerator or use ice packs against your part. Do not submerge the ComposiMold in water to cool.

How long it takes to solidify depends on the shape and size of the rubber mold. The larger the mold size, the longer it will take. You can speed up the solidifying by putting the mold in a refrigerator or freezer or using an ice pack.

Do I have to take my dog to the vet if he/she ate some ComposiMold?

ComposiMold is non-toxic and is made of food safe materials, however if materials such as urethanes, plasters, mold release etc. are used in the mold than the material is no longer non-toxic and the MSDS for those materials used in the mold should be looked at regarding their safety for consumption. Many dog owners witness their dog eating ComposiMold ( Dog's love the stuff), so far all of the dogs turned out to be fine. in the worst cases The dog had gas or threw up the ComposiMold. However If you feel your dog is not acting normal than play it safe and get him looked at.

What happens when the ComposiMold get dirty? How do you clean the ComposiMold?

You can filter the ComposiMold of any particles or pieces. The Starter Kit includes a funnel and two filters to use if the ComposiMold becomes dirty from the casting materials. You can also purchase these accessories separately through our online store.

To filter:

  • Place a filter into the funnel
  • Hold the funnel above a container that can withstand the hot ComposiMold
  • Melt the ComposiMold as previously discussed
  • Pour the ComposiMold through the filter and into a second container

Can I wash ComposiMold with soap and water?

ComposiMold is an eco friendly biodegradable material that will dissolve in water over time, especially hot water. Use a cold, damp cloth to wipe and clean the ComposiMold. Then dry it with a paper towel or cloth.  


Melt the ComposiMold back down after wiping clean and store covered until your next project. If you plan to re-use the mold to make more castings, store it in the freezer to remove any tackiness from cleaning with the damp cloth.

What are the advantages of using ComposiMold mold making materials over Silicone molds?
ComposiMold is a less expensive (definitely cheaper in the long run) rubber mold for plaster casts, plastic casts, and others. The rubber mold is much more forgiving in terms of allowing you to fix mistakes (Reheat or use a heat gun to heat an area). The silicone molds are typically longer lasting for single rubber molds, although after they start to go bad, you can not fix them or recast them. One of the initial ways we started using ComposiMold was for a backing to brush-on silicone mold making materials and polyurethane molds because you can use very little of the silicone mold material and reduce the mold making costs.

What types of Materials can be cast with ComposiMold?

You can use many casting materials in the ComposiMold rubber molds including:

  • plaster or gypsum, concrete: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.
  • 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!

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.

Can ComposiMold be used to cast silicone objects?

Yes, spray your mold with silicone mold release. Measure and mix your silicone according to the instructions given on the container or flyer (different types of silicone have different mix ratios). Then pour your silicone mixture into the mold and wait for it to solidify before removing

Can I use ComposiMold for polymer clay push molds?
Yes, we recommend using the ComposiMold-Firm for polymer clay push molds because of the higher stiffness. Make the mold as you normally would using ComposiMold. Press in the clay to make the shape. If necessary, place the rubber mold into a container to provide stiffness to the rubber mold while pressing in the polymer clay.

Can I produce a ComposiMold mold from a wax, Plasticine, Castilene or Monster clay sculpture?  

Yes, wax and wax based clay sculptures typically have a melting point of about 160 Fahrenheit. Before pouring ComposiMold over your sculpture, make sure the ComposiMold is not to hot, wait until it reaches 145 Fahrenheit or less before pouring. If you want to be extra carful not to ruin your sculpture cool it in the fridge or freezer.

Will the heat created by my resin melt the ComposiMold?

ComposiMold works great with many resins. ComposiMold has a melting point of 130 Fahrenheit and will melt when exposed to temperatures above this melting point. ComposiMold can handle temperatures up to 180 Fahrenheit if the mold is chilled in the freezer prior to pouring the resin.

The amount of heat created by a resin depends on a number of factors:

  • The size of the mold: larger projects generate more heat. Start small.
  • The temperature of the mold and the room: less heat will be produced when the resin is exposed to cooler temperatures.
  • The type of resin: All resins will vary.
  • Additives: most additives such as colors and fillers will slow down the cure and reduce the heat produced (this is usually a minor change)

How do I make a two part mold? How do I keep the second half from melting the first?

There are a couple different methods for creating a two part mold, the easiest method is to pour the entire mold and cut the mold in half afterward. The more complicate method requires pouring two mold halves.

Creating a mold with two halves:

  1. First Push the object into clay and shape the clay so that half of the object is covered in clay. This is a very important step if you want to minimize seam lines and control how the two parts come together.
  2. Place the object into a mold box. At this point spray or brush on a mold release. Next spray a medium coat of Bubble Buster.
  3. While the Bubble Buster is still wet, pour the melted ComposiMold until it covers the entire exposed half of the object.
  4. Allow the ComposiMold to solidify by cooling.
  5. Before pouring the second half, remove the clay, coat it with mold release and cool the first half in the freezer. Wait until the liquid ComposiMold has cooled but is still pourable before pouring it over the first half. The ideal pouring temperature is between 120 to 135 F.
  6. Now wait for the second half to solidified and you have your mold!

Check out our two part mold step by step guide with images and a video in link below:

How To Make A Two Part Mold And Cast Crystal Clear Medieval Knight Action Figures

Do you need a special mold release when molding with ComposiMold?
We sell a mold release that has worked well for us for mold making and casting, but many other mold releases also work well. Petroleum jelly (Vaseline), cooking spray, vegetable oil, mineral oil, and others will provide the necessary separation in your molds. With all mold releases, be sure to wipe off any excess material from your mold. The best bet for determining the effectiveness of a specific mold release is to experiment and that is also one of the major benefits to ComposiMold-try it and reuse it.

 How do I remove or minimize bubbles in ComposiMold?

 Check out our blog: How to remove and minimize bubbles in ComposiMold

The bubbles could be caused by quite a few different things: If your original master part is not sealed correctly, bubbles may come out from the part. This is probably the cause if you are using plaster, clay, or wood as the master. To solve, seal the master first with several layers of polyurethane spray or wood sealers. Elmers-like glue (PVA glue) works well to seal parts. In some cases petroleum jelly can stop the air from escaping your original part and also act as a mold release.

We recommend using Bubble Buster. This reduces bubble formation during mold making by reducing the surface tension so the bubbles rise up and away from the master.

You may have too much mold release, so the interaction causes bubbles. This seems to happens quite a bit when you use a vegetable oil as a mold release, but other mold releases may have this affect. Be sure to wipe off any access.

You may have bubbles in the ComposiMold from bubbling in the microwave. It may be worthwhile to remelt the ComposiMold and let it cool at room temperature so the bubbles can rise to the top and escape.

You may be putting bubbles in when you pour the ComposiMold into the container. The best way to avoid this is to just pour gently into the lowest area of the mold so the ComposiMold rises up over the part. Be sure any holes are filled with the ComposiMold and you are not trapping air.

You can also do quite a few things to get rid of bubbles that are in your mold while the mold is still liquid:

  • You can use a toothpick or other object to push out the bubbles. This works well in small cracks or under undercuts
  • Before sticking the ComposiMold in the freezer to cool, let it sit out for about 10 minutes to let the bubbles rise to the surface.
  • Vibrate the part by pushing on the sides or even better a back massager against the mold sides.
  • You can also paint on a thin layer of ComposiMold over the areas where the bubbles are forming. If you let this cool, you can be sure the bubbles won't be against the master part.

 Bubbles are forming on my casting, what is causing this?

Sometimes when you do the casting, bubbles form because the heat from the resin (polyurethane and even hotter for epoxy) melts the ComposiMold. You can reduce the amount of exotherm by adding fillers into the resin so the resin mass per volume is less. The filler also absorbs some of the heat. Some potential fillers include: plaster, sand, flour, microballoons, and fiberglass. Many specialty fillers are available.

 My ComposiMold has bubbles trapped in it, how do I get them out? 

Remove excessive amounts of bubbles by heating the material in a double boiler or in a oven/toaster oven (use an oven safe container) set to no higher than 170 Fahrenheit until the majority of the bubbles have risen out of the material. Remove the material from heat as soon as the bubbles are removed (typically 1 - 3 hours). Heating ComposiMold longer than necessary and overheating the material will shorten its life.

Can I use ComposiMold to make molds of food?Yes! All ComposiMold mold making materials are food contact safe. ComposiMold-FC (food contact) is specifically for use with foods. ComposiMold has been used for molding chocolates, fondants, gum paste, marzipan, and gummy recipes (gummy bears). It can also be used to make molds of foods (strawberries, banana, bacon etc.).

How do I make my chocolate glossy? Temper your chocolate: Tempering chocolate means to melt it so slowly so that it never goes above 100 degrees Fahrenheit. Adding food grade paraffin wax to your chocolates and coating them with oil will also increase the chocolates shine.

Why would I want to use ComposiMold to make molds?

ComposiMold is a unique, innovative mold making material designed to enhance you mold making experience. The ComposiMold is a reusable rubber mold making material that can make many molds and castings with only one mold making material. ComposiMold provides a unique solution to sculptors and artists by allowing molds to be easily fixed by either using heat to reshape the mold or by re-melting the composite and starting the mold over.

The current record for the number of unique molds made with the same ComposiMold is over 50 times. For this test, the ComposiMold is melted, a mold made, a part cast, and the cycle repeated. Below is an image of the parts cast.

multiple unique molds

ComposiMold's rubber mold formulation provides a stable system with good mold strength, elongation of 150%, and longevity. ComposiMold is the easiest, flexible molding system available: melt, pour, and use. It is also important to note that no dangerous chemicals are used in the rubber mold and therefore safe for both the end-user and the environment.

ComposiMold's key advantage over other mold making materials is the fact that the product is reusable. Compared to other mold making products, ComposiMold has lower costs. Since the mold can be reused multiple times, the more you use the product, the more money you save. When learning to mold this is a very unique feature and when developing your castings, reusability of the rubber mold can provide dramatic savings.

[graph] cost per unique mold for casting

[graph] total cost to make molds for casting

Another advantage over competitors is that ComposiMold is safe for the environment. The composition of the product does not include petroleum or petroleum byproducts and if composted the material will biodegrade. Also, no dangerous chemicals are used during the production of the material.

ComposiMold is the easiest mold making material to use. The product is melted in the microwave and then used to create a mold of an original master piece. No weighing or mixing is necessary to complete the molding process.

ComposiMold is a rubbery, flexible resin made from a proprietary blend of environmentally friendly materials. Unlike most flexible mold making materials, ComposiMold is a thermoplastic resin that can be melted continuously.

A rubber mold is made by making a negative shape of an original master piece. This original master may be a figurine, action figure, toy, scientific instrument, sculpture, or any other piece you would like to mold. The melted ComposiMold is poured or painted onto the original and allowed to solidify by cooling. The time it takes for the ComposiMold to cool depends on the size of the mold. The master is then removed and the casting material is poured or pressed into the rubber mold cavity. You can make plaster casts, resin casts, plastic casts, and concrete casts. Casting materials may be polyurethane(urethane), silicone, epoxy, plaster, concrete, polymer clay, chocolate, or others.

Where Can I Buy ComposiMold ?
Buy Locally or Our Online Store. Online Store for all Your ComposiMold Supplies
Can I get the SDS for ComposiMold and ComposiMold's products?

Download Bubble Buster SDS

Download Clear Casting Plastic SDS

Download ComposiMold (LT-Original) (FC-Food Contact) (Flex) (Firm-PowerMold) SDS

Download ComposiStone MSDS

Download Creative PaperClay MSDS

Download IMPRESSive Putty (ReMold Putty) SDS

Download Vegetable Oil and Food Contact Safe Mold Release SDS

Download ImPRESSive Putties Activator SDS

Download ComposiCast Part A SDS

Download ComposiCast Part B SDS

Can you make a mold for me?

We typically sell the mold making material to make molds yourself but, we can create molds for you as long as the original parts is your own design. Please contact us for pricing details. Email [email protected] or call 1-888-281-2674.

Can I use ComposiMold for body casting?

ComposiMold is not recommended for body casting because it has the potential to cause burns. ComposiMold has a melting point of 135 degrees Fahrenheit and, It will typically be between 150-180 after melting in the microwave. ReMold Putty can be used to make body and paw impressions.

Does ComposiMold Shrink? How does it Compare to the shrinkage of other mold making materials?

Unlike many other mold making materials ComposiMold is a hydrocolloid based mold material, which means that its shrinkage is affected by humidity and time. The shrinkage can be controlled by storing the mold in a sealed bag or a sealed container. If you store the mold in a tightly sealed container the mold shrinkage can be as low as .1%. If the mold is left out on a dry winter day the mold can shrink by 2% in 24 hours, and will shrink even more if left uncovered.

Rubber Mold



2 - 5%


5 - 20%

Urethane Rubber

1.5 - 3.5%


80 - 85% over a few days


80 - 85% over a few days

Homemade Silicone Molds Oogoo

20 - 60%

Would you like a copy of our Instruction Brochure?
Download a .pdf version of our food contact ComposiMold Instruction Sheet Here
Download a .pdf version of our general ComposiMold Instruction Sheets Here  

    Please contact our customer support team at: [email protected]
    or call Toll Free: #1-888-281-2674 MON-FRI 8-4