Mold making with tin silicone

Deer skull and antlers

The first set after picking out the deer skull is mapping out out on a piece of foam board the shape of the skull





Step two cut out pieces of sponge to fill in the larger holes(eye sockets) so the silicone will not leak through.

Step three cut off the antlers and set aside to be molded separately than with chavant clay fill the eye sockets, nose, and any other holes that would leak silicone out of them. Try not to lose too much of the bone detail.

Cut out your foam to make a skirt like wall around the skull. Try to get the best fit with few gaps.

Lay your skull on a cloth so that it will not move too much when you are working.

hot glue on the bottom of the skull in a few spots the skull to the foam. Turn it over and using the chavant clay fill in any gaps between the skull and foam. Do this all the way around. A good trick is to hold it up to a light and if you see any light coming through it needs more clay. (*make clay level to the foam so it doesn’t stick out more.)

Add a layer of tape around the foam making a wall.

Also add several worms of clay around the skull.

Now it’s ready for the first layer of tin silicone

The first layer is always the thin layer so you can capture the most detail.





Tin Silicone

When looking for the right silicone there are two important numbers to look at.

1.Durometer- The higher the number the more rigid. The lower the number the softer.

2. Elasticity- the higher the number the more flex.

*when silicone is on the scale at desired weight pick it up and put it back down because sometimes air bubbles are trapped and it will not show the true weight.

*whatever the base weight is you add 10% catalyst

*always shake catalyst in bottle before using

*once silicone is fully mixed meaning there is no swirling of colors place into a degasifier for 2 minutes

Silicone times

Gel time

Set time

Demold time

Shore time

*always start with tin silicone once a master positive of whatever you are molding is made and you want to make more for production then make a platinum mold.

Platinum has longer life span so is good for production.

Bad things about platinum silicone is it will not work if contaminated by sulfur (hands, latex gloves, wooden stir sticks all have sulfur)





Now that the silicone has been gasified pour the first layer of silicone. Ribbon(looks like ribbons) in small circles pour over all the bone in a thin layer but making sure to cover all the bone. It’s ok if you see through the thin layer.

Save some of the thin layer silicone once the skull has a base layer. Take out the airbrush and blow air over the skull to get the blow outs and air pockets out. For the undercuts on the skull pour the remaining silicone while using the and blow the silicone onto the undercuts and problem areas. The air brush helps you control where you need the silicone to go.

Now wait for the first layer of silicone to set.

Now for the 2nd layer of silicone will be a little different

This layer will be thicker.

Silicone 2nd layer

*shake catalyst

*10% catalyst??

*10% thicker ??

Poly fiber 2?

*degasifier 2mins

Now let the 2nd silicone layer set.

Next layer is two part plastic urethane

Measure equal parts and add poly fiber 2

Bottom side of skull

Finished