Dec 11, 2018
Silicone sealant is a wonderful product that has a hundred uses around farm shops. Here are some basic facts about that miracle-working goop:
-"RTV" seen on many silicone sealant labels stands for "Room Temperature Vulcanizing." Which means that particular silicone sealant will cure without any special treatments or conditions.
-Which is misleading, because the cure-time of RTV sealant is not based on temperature. Cure-time is related to the amount of humidity in the air. Interaction with water vapor/moisture in the air triggers the chemical reaction that cures silicone sealant. When it comes to curing silicone, it truly isn't the heat--it's the humidity. That's why you have to work faster on a hot, humid summer day to get pieces assembled before the silicone "skins over," compared to when you're working in a heated shop on a low-humidity winter day.
-Less is often more when applying silicone. If you're using silicone as a gasket material, the goal is to apply just enough silicone so when the pieces are assembled, there is just a slender thread of silicone extruded along the joint. Big gobs of silicone hanging from the joint creates a risk that one of those blobs will break free and plug an orifice or passageway elsewhere in the machinery.
-Speaking of engines, experts at Henkel/Loctite tell me RTV silicone that smells like vinegar is NOT recommended for use in engines or around electronic circuitry. The vinegar odor is due to the volatilization of acetic acid as the silicone cures. Acetic acid vapors in a confined area can aggressively corrode unprotected metal and electronic circuitry. Always use "dielectric" silicone or a silicone that doesn't smell like vinegar when assembling engines or around electronic circuitry to avoid causing corrosion .