Mold silicone rubber is two-component RTV silicone rubber mold making general before, check silicone flowability, A component is a viscous liquid, also white color, but also according to user requirements, tune into each colors silicone liquid at room temperature about 25 degrees, the viscosity of the silica gel is generally about 35000CPS, silica gel viscosity is too large, it will cause uneven mixing silicone curing agent, made out of the mold with dry uneven situation, the correct use the way is:
1. Silicone and curing agent according to a certain proportion of added standard ratio, the ratio of silica gel and the curing agent is 100: 2-100: 5, the greater the amount of curing agent, the curing time is faster, shorter operation time, appearance liquid silicone mold flow, a component is silica, component B is the curing agent. Example: Take 100 grams of silica gel, 2 g of curing agent (Note: Be sure to silicone and curing agent Stir, stir if not, there will be a mold has been cured, an uncured silicone will appear uneven drying and curing conditions, it will affect the life of the silicone mold and turning model number, or even result in scrapping the original model).
2. Vacuum row bubble treatment: silicone and curing agent Stir to vacuuming process, under normal circumstances, evacuation time should not be too long, under normal circumstances, not more than ten minutes, vacuum for too long, silicone immediately curing, resulting in a crosslinking reaction, the silica gel into a piece, can not insulate paint brush or perfusion, thus wasting silica, silica gel is poured into the trash only, re-take the silica do.
3. Process priming operation: the smoked vacuum exhaust bubbles over silica gel, brushing or pouring ways to silicone poured in the product above (NOTE: The product or model to be copied down before silicone release agent or release agent is absolutely necessary ). Then put in the product above silicone brushing, brushing must be uniform, 30 minutes after you paste a layer of gauze or glass fiber cloth to increase the tensile strength and silica gel. Then brushing a layer of silica gel, and then paste a layer of gauze or glass fiber cloth, so after twice on it. Only by doing so, open up the silicone mold life and turning model number will relatively improve a lot to be able to save costs and improve efficiency.
4. Outer mold production: The general approach is to mold around with a plastic sheet or boarded up, one is surrounded with plaster mold, filled with plaster on it and another resin brushing way, the coating brush a layer of resin paste on a layer of glass fiber cloth, then brushing then paste, repeated two or three to complete the outer mold die.
5. Now listed hardener and silica gel (silicone) ratio of reactions: One is the reaction of the company's drying and curing agent mixing ratio of silica gel
① curing agent plus an amount of 1%, 2.5 hours colloid is still flowing, 6-8 hours to release.
② hardener plus 2%, 50-1 minutes gum will flow off, 2-3 hours to release.
③ curing agent plus 3%, 28-30 minutes colloid is still flowing, 1.5-2 hours to release.
④ hardener plus 4%, 10-15 minutes colloid is still flowing, 1-1.5 hours to release (Note: The maximum amount of the curing agent is not more than 5%, more than 5% of the curing agent time is too fast, not normal use, resulting silicone mold scrapped).