mb
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Posts: 2
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Post by mb on Dec 27, 2015 20:12:12 GMT -5
I saw a youtube video where a sculptor expanded a mold (I believe it was a Alumilite High Strength 2 silicone product). He soaked an existing mold in mineral spirits overnight, and the mold expanded about 25%. I believe the result was temporary. A similar video showed adding mineral spirits to the mixture for High Strength 2 in order to shrink the mold.
Question: Is it possible to expand an existing mold using mineral spirits? How long lasting are the results? Anyone with experience or know of negative results?
thank you.
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Post by mike on Dec 28, 2015 9:17:06 GMT -5
Yes, you can expand our silicone rubber molds using Mineral Spirits. We used Odorless Minerals Spirits to be exact. Is it an exact science? No. Wall thickness and mold dimensions will vary the swelling/expansion. IF you have a thin wall part of the mold and a thicker section, they will swell at different rates which may warp your casting. The swelling is temporary and the mold will return back to its original size and shape once all of the mineral spirits evaporate which may take up to a week. Once the mold has swelled up, the tear strength will be much less and care needs to be taken with them mold. That is why we typically use the High Strength series silicones for this process. Even after expanding, it typically has enough strength to pour a part which will create a new master that is X% bigger depending on how long you leave it in the mineral spirits. Depending on the part, the mold may still tear due to undercuts or the force required to remove it from the mold.
There is also no set time to reach a specific percentage of expansion because it will vary based on the thickness of the mold. So it is highly recommended to carefully watch and then measure the mold frequently to know the best time to remove it from the mineral spirits, dry, and then cast your new master.
Mike
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mb
New Member
Posts: 2
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Post by mb on Dec 29, 2015 7:28:48 GMT -5
Mike, Thank you very much for the prompt reply. You answered my questions perfectly. cheers, mb
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