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Vacuum vs Pressure pot
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I would:
1.measure and degas both parts A and B
2.mix and degas
3.pour and degas
That works best with the longer setting silicone. If it cures fast you don't have time for all the degassing. Silicone with a shore of 10 works best! The softer the better. I recommend dragon skin 10 from smooth-on.Comment
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Ah! yeah, that makes sense... where even small internal bubbles can become a big issue, akin to casting in fine metals.Comment
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Yeah,internal bubbles are a bad thing.Another issue i've had is when sanding on some resin parts you expose internal bubbles making them external bubbles that you then have to deal with.I gotta go bubble-free! Thanks for your help.Comment
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Not trying to bust any bubbles (sorry I couldn't resist it...).
You can in fact pressurize your molds as you make them, no de-gassing needed... then using the same tank pressurize your cast... I am sure de-gasing your silicone is a great thing to do, never tried it, but it is not necessary to get perfect bubble free molds or casts...
Been doing it 13 years and I get flawless molds and casts... Now having said that, if you don't pressureize your molds when making them, you CANNOT, cast resin in them under pressure this will cause the resin to seek out surface weak spots (caused by air bubbles) and give your piece little round zits all over it...
Pressure tank is really all you need IMHO.
DaveLast edited by David Lee; Jan 20, '13, 3:05 PM. Reason: cause I can't spell or proofread to save my lifeComment
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Not trying to bust any bubbles (sorry I couldn't resist it...).
You can in fact pressurize your molds as you make them, no de-gassing needed... then using the same tank pressurize your cast... I am sure de-gasing your silicone is a great thing to do, never tried it, but it is not necessary to get perfect bubble free molds or casts...
Been doing it 13 years and I get flawless molds and casts... Now having said that, if you don't pressureize your molds when making them, you CANNOT, cast resin in them under pressure this will cause the resin to seek out surface weak spots (caused by air bubbles) and give your piece little round zits all over it...
Pressure tank is really all you need IMHO.
DaveComment
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-DaveComment
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Good silicone is also key, don't buy cheap crap...I have molds that are 8-10 years old, but they are made from good silicone. The two best in my opnion are Dow Corning V and Dragon Skin 10 from Smooth-on... I use the Dragon Skin 10 quick set (75 minute set time)... The Dow Corning is a better product for longevity but it's more expensive and takes longer to set up. Dragon Skin is cheaper, easier to get, and works great for one and two part molds.
-DaveComment
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