silicone RTV hardness recommendation for pressure casting ?

Jul 13, 2003 2 Replies

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Jack 23 years ago

Hi,

I am trying to make a mold of a perfect cube from which to cast polyurethane resin into (10"x8"x5") and I want to get a lot of castings with as perfect a surface as possible to minimize machining afterwards. The mold will be split in 2, and I will cast uner 60 PSI in a pressure chamber... I wanted to ask hardness rating of silicone RTV I should go with ?? The harder the better ?? I was going to go with a platinum cure 40 shore A hardness silicone, but I have heard ones as high as 60 exist out there...(and I only want to do this once!!!!)

Thanks,

Jack

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Richard Lamb 23 years ago

and it's gotta be --- perfect!

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Bob May 23 years ago

Don't bother with the silicone but rather make the mold from something good and solid. A cube can be cast without any mold release problems if you look at how you can follow the edges and not have any capture mechanism. There are only 6 sides to a cube.

-- Bob May Losing weight is easy! If you ever want to lose weight, eat and drink less. Works evevery time it is tried!

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