Rubber mold temperatures


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Posted by David E. Conway on August 16, 19100 at 10:46:55:

The post by Harry (bronze and rubber molds, posted 8/12/2000) brings up an interesting question � what is the highest molten metal temperature that silicone rubber (or other) mold material can withstand? I have used BJB silicone rubbers for years and cast pewter and other �white metal� alloys in them for years. I have poured as high as 800 degrees F. without so much as a scorch to the mold. This rubber is extremely durable and I have stored molds that are at least 15 years old and showing no signs of wear or deterioration. I often cast hollow sculptures devising a plaster-based core, and have continue to use a mold for numerous castings.

The BJB literature says that their TC �5050 can withstand up to 850 F., but can be pushed possibly to withstand higher temperatures under certain conditions. I believe these factors are the thickness of the rubber and the amount of time the rubber is allowed to cool between pourings. Their rubber is more expensive than others, but worth it in the long run. For those interested, BJB Enterprises is located at 13912 Nautilus Dr., Garden Grove, CA 92643, Tel: (714) 554-4640. They also have a web site. A gallon of TC-5050 goes for about $125.00, and it I also available in pints and barrel sizes.

I have heard that GE also makes a high temperature silicone, but I have been unsuccessful finding a dealer or literature concerning this product. I would appreciate any leads concerning GE�s silicone rubbers.

Does anyone have any experiences casting higher temperature metals into silicone molds? I�m willing to bet that aluminum could probably be cast successfully into silicone rubber, without damaging the mold.

Does anyone know of any research and development that is being conducted into rubbers? Imagine rubber molds that could withstand repeated bronze pourings! No more pulling waxes, or messy ceramic shells or investments. Just make one mold and pour away your edition. Hmmmm, sounds too good to be possible�.or is it? Don�t some silicone caulkings withstand temperatures well up into the 1,500 Degree F. range and above? Food for thought.

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