HOW TO: silicone mold making

How to create a silicone mold using silicone caulk

This post covers the creation of a 4 part mold for a human form. 2 part silicone 2 part plaster. The idea behind this combination is that the silicone portion of the mold is what comes in contact with the cast object and the plaster holds the silicone in position.




Preperation
Source silicone
You can buy silicone at most hardware stores, make sure that you are using 100% silicone for this project.
Object to be molded
Get the object you want to make a mold of, for this project I will be using the mold and form from the HOW TO : make a two piece plaster mold post





Step 1: Lube it up
Coat the entire mold with Vaseline, This will prevent the plaster from sticking to the mold. Use you finger to apply the bulk of the vaseline and then use a paint brush (one you will never use again for painting) to get into the edges and cracks of the form and mold.

Step 2: Catalyzing solution
Mix concentrated dish soap at a 1:10 ratio with warm water (Below). You are making a  catalytic bath for your silicone. The glycerine in the dish soap accelerates the cure process for of your silicone AND makes it possible to handle the silicone with your bare hands.Make sure that this mixture is right next to the objects that you want to be making molds of as you will be placing the silicone into the solution then directly onto the objects.

Step 3: Preparing the silicone

Cut the tubes of silicone open (pictured below). Submerge your hands completly into the catalyzing solution rubbing some up to your elbows, this will prevent the silicone from sticking to your skin. 

Then carefully using your fingers scoop our all of the silicone from the tube and place it in the catalyzing solution. After a few seconds it will begin to change color. Form it into a ball, and slowly massage it. Fold it, stretch it out, and work it like knead dough until it becomes less maluable ( appox 30 seconds). 

Step 4: Application
Take the silicone out of the catalyzing solution and place it onto the center of the object being molded. Then gently kneed the silicone out until it is covering the entire form.





Step 5: Registration points
Now create small nodules with some silicone and place them at the center and extremeties of the form. These will be for the hard shell that will encase this mold.




Step 6: Allow to dry
The silicone will be touch try in approx 5mins. And usable within the two hours (normally 24 hours). During the curing process the silicone will give off a VERY strong an odour.

Step 7: Hard casing
The final step is to create a plaster hard mold that goes over the silicone. Due to the flexibility of the silicone it will lose shape easily . Creating this hardcase allows you to compress the soft mold when using non-liquid materials.

Step 8: Releasing the molds