Mosites #14287 Silicone Pressure Distribution Pad Rubber
Mosites #14287 silicone compound is a high hardness formulation that is sold in an uncured, calendered sheet form. It is unusual in that it can be co-cured in contact with typical epoxy prepreg reinforcements to fabricate stiff pressure distribution pads or caul plates. Since it is a silicone based product it has excellent resistance to high temperature exposure and natural release properties from accidental or intentional contact with epoxy resin. These properties can be improved by overcoating with Mosites #14232 Release Coating or application of approved release agents such as Freekote #700 before autoclave vulcanization of the composite article. By using epoxy prepreg reinforcement (either carbon or fiberglass fabric ) the elastomer can be stabilized to yield negligible shrinkage values in service.
Lay – Up and Cure Procedure for Mosites #14287 Silicone
- Clean and prepare the tool form in the usual manner for a lay-up procedure.
- Apply a release coating to the tool. A dry, uniform coating of Teflon Aerosol Spray is recommended. DO NOT use a silicone base mold release.
- Lay the first layer of Mosites #14287 uncured silicone into position on the tool. Using doubled nylon fabric and starting in the middle of the sheet, apply pressure to remove air that may be trapped under the first layer.
- Lay prepreg reinforcement into position. If desired, a debulk cycle can be applied using standard bagging techniques.
- Apply the top layer of Mosites #14287 silicone sheet and remove any entrapped air in the same fashion as step #3.
- Apply FEP release film to the layup and remove any wrinkles or air pockets.
- Vacuum bag the layup in standard fashion using breather / bleeder system under the vacuum bag.
- Cure the laminate by the epoxy prepreg manufacturer’s recommended cure cycle. Mosites #14287 requires at least 30 minutes at 300 degrees F for proper vulcanization. A pressure of 60 psi is recommended for the autoclave cure pressure. Longer cure times or higher cure temperatures or pressures to facilitate the epoxy resin cure system will not adversely affect the silicone properties.
- Allow the part to cool and remove it from the tool. If any areas require patching they can be repaired using uncured #14287 sheet. Be sure the rubber surface is cleaned to remove any residual release agent and repeat the cure cycle.
- No post cure is necessary.