Filling the Mold
Prepping the mold is the first order of business. Depending on how long it's been since the mold was made, it might need to be cleaned again to ensure that no co ntaminants such as dust and stray hairs have found their way onto the negative surfaces of the mold interior.
Once the mold pieces are clean and dry (if they're stone molds) they will need to be sealed and rel eased; if the mold is made of fiberglass or other resin, it prob ably doesn't need to be released, though it's never wrong to release a mold if you have any doubt as to whether the silicone will stick or not without it. If you will be casting silicone into silicone, this is very important: Tin silicone can be cast into a mold of either tin or platinum silicone (the mold must be properly released, of course) but platinum silicone can be cast only into a platinum silicone mold , not a .tin silicone mold .
InjectionFilling
To inject siUcone into your mold, at least two holes must be drilled in the mold
• positive: one to inject silicone through and the other to allow air to escape as the mold fills. The syringe for injecting the silicone should be made of polyethylene or polypropylene and should not have a latex rubber end on the plunger; that would cause platinum silicone inhibition-it won't cure. Make sure the mold pieces have been thoroughly released, including the injection hole and the vent
hole.
1. Release the mold pieces.
2. For creating a GFA, brush or stipple a thin coat of mixed silicone encapsulator material on both halves of the mold, positive and negative. Be careful not to stipple silicone over the cutting edge of the appliance mold.
3. When the encapsulator material begins to set, close the mold and clamp or bolt securely together.