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How to Make Molds

 

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Molds can be as simple as pressing the part into the ImPRESSive Putty or pouring ComposiMold over your part. Molds let you duplicate your creations into different materials. Into real parts. Learn more by going to a specific topic:

 Mold Making Basics

Mold making is the process used to duplicate three dimensional models. Through the use of a mold making material (or mould making if you're in Europe) a negative of a model part is made. That negative can be used to cast a second part that is identical to the original part in size and shape. The same mold can be used to make duplicates of the original Master parts.

And ComposiMold and ImPRESSive Putty are re-usable molds. You can re-melt and re-use as many times as you want as long as you don't overheat the mold making material (boil it too many times). 

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1 part Mold with ComposiMold  

 

One part mold making is used when your part has a flat surface on one side such as a relief sculpture. Anything that can stand up on it's own can be molded using the one part molding process. The process becomes very simple, especially with ComposiMold because you don't have any mixing or weighing. Select a mold box that your part will fit into with at least a 1/2 inch around the sides. Plastic cups, bowls, even aluminum foil works well for the mold box.

  1. If you part is lightweight (such as a plastic toy) hot glue or use a tape dot to hold your Master down in your mold box.
  2. Spray your part/Master with mold release.
  3. Spray liberally with Bubble Buster to reduce surface tension.
  4. Melt the ComposiMold as described in the included instructions. You don't need to melt everything, just what you need.
  5. Let the ComposiMold cool to solidify. Place in the refrigerator or freezer to cool faster
  6. Pull the mold from your mold box and pull out your Master from the bottom of the ComposiMold
  7. Pour or press in your casting material
  8. ComposiMold is a remeltable rubber, so when finished with that mold you can remelt it to make a New mold.

 The depth of the part does not have to be shallow. For example candle molds are typically long and narrow, but can still be molded using the simple process for one part molds.

The casting material is poured or pressed into the mold indentation. Mold sizes can range from a few millimeters to many feet in size.
 
Mold making is used  to make duplicates of a wide variety of creations ranging from car parts to Christmas ornaments. Why you would want to make your own molds depends a lot on what you are making. The mold can then be filled with casting materials of your choice. For example, many cake decorators or chocolate makers use molds to create unique shapes from their chocolates or use molds to shape fondant into special shapes. Home soap and candle makers enjoy duplicating unique shapes and designs that cannot be found. Hobbyist, such as those in the train hobby, enjoy making components for their trains or improvements to the backdrops for the train sets. Or fishermen enjoy making their own unique fishing lures.

1 Part Mold with ImPRESSive Putty

The ImPRESSive Putty allows you to make molds without a mold box, fast and easily.

 

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Brush-on Molds with ComposiMold

Sometimes the shape you want to duplicate cannot be placed into a mold box. ComposiMold is an easy mold making material for the brush-on mold making technique because of the change in viscosity as it cools. Brush-on, or paint on mold making, works by encasing the part you are making in the rubber mold making material and building up layers.

 Tip: Apply the melted ComposiMold at it's coolest melted temperature, which is 130F. This will keep it from dripping right off your shape. 

 
      
 

Push Molds

Clay, Polymer clay, Polymer Metal Castings, and air dry clays can be used in ComposiMold or ImPRESSive Putty molds for very fast castings. Push molding uses a relief sculpture shape to make the mold so you have an opening to push in the clay. You can also make push molds by pressing the clay between two mold halves.  

 

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Cut Block Molds

This cut block molding process can be used for most shapes. It is basically the 1 part mold making method where you cut down the sides. This tutorial uses a small football player figurine. 

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Start with a touch of polymer clay, a figurine like this football player, and a cup. Instead of clay to hold the figure down, you can also hot glue the figure to the bottom of the cup.

Now, we spray a little Bubble Buster over your figure to reduce surface tension so bubbles are less likely to stick to your part.

The ComposiMold is melted in the microwave. For a small container such as this 10 oz. container, it took about 50 seconds to melt. You only need to melt what you need, but if you melt too much don’t worry. It will still be good for next time you need it. ComposiMold is used because it can be re-melted and re-used for dozens of molds using the same molding material.

Another nice thing about ComposiMold is that it is relatively transparent so you can see where the bubbles may stay. Like any molding material, bubbles can still become stuck in any crevice or undercut. Use a paper clip to pull the bubbles away from the potential problem areas such as the neck and under the arms.

The mold will cool to solidify. This mold will take about 30 minutes to cool in the freezer.

We pull away the cup that was used as your mold box. You can also use legos, wood, plastic, or even aluminum foil to make your own mold box.

Now to pull out the original figure and prepare the mold for casting, we need to cut where we want the parting lines to be.
We do this with a knife, scissors or an exacto knife.
We also need to cut between the legs to get the figure out. With this figure, you can see the parting lines from the original figure, so it was a matter of following the same lines.

We are now ready to make the casting. We use ComposiCast White resin, which is an epoxy resin that mixes 1:1 and works fantastically with the ComposiMold and ImPRESSive Putty.

After mixing, we use a syringe to push the resin into the areas where we know there will be difficulty. Because the arm is facing the way it is, we know the resin will not flow into it, so we push some resin in before we put the two halves of the mold together. Just in case, we also put some resin into the football hand and the persons head and helmet.

Now we close the mold up, and tape it shut. We then pour more resin into the base and through the legs. To make sure all the areas are filled, we squeezed the mold and bubbles rose up and out. The resin is then pulled into the mold cavity to fill where the bubbles were.

The ComposiCast solidifies in about 16 hours, so we leave it overnight, and we are ready to pull the part out of the mold. We have two worries when pulling apart the mold. The most important issue is to make sure we don’t break the part, and the second concern is to try not to rip apart the mold. We want to be careful on the hand because the resin is thin, and also between the legs we want to pull away the mold without causing damage.

And here we are, the casting is complete. At this point you can cast another, or you can re-melt the mold and make a new shape. If you want to keep the mold for long periods of time, wrap it in plastic wrap or a ziplock bag.

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2 Part Molds with ComposiMold

Two part molds allow you to duplicate more complicated objects than can be molded with one part molds. The two part mold making technique can provide excellent details and precision for your duplicated parts. The process is effective with large and small parts for duplicating jewelry to large concrete sculptures. Although it seems complicated, the 2 part mold process becomes extremely easy with practice.

    

You can also pour half of the two part mold at a time to make two separate halves. This is a full two part mold and used when you want to place the parting line in specific parts. The advantage of 2 part molds with ComposiMold is that the molds can be remelted afterwards to make new molds. It allows you to experiment with your mold making techniques.

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2 Part Molds with ImPRESSive Putty

 You can also make two part molds with ImPRESSive Putty. The two halves of the Putty won't adhere together as long as you keep one side cool.

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