Author Topic: Need Help with Casting Resin Disaster  (Read 2151 times)

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pnolan48

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Re: Need Help with Casting Resin Disaster
« Reply #15 on: August 27, 2014, 08:54:54 AM »
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. . . Took hours to clean up the mess.

Yep. And half a roll of paper towels, some of which are now sticky-attached to a waste basket. I now shake the bottles vigorously at least 100 shakes, and let the bubbles settle out before mixing.

kornellred

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Re: Need Help with Casting Resin Disaster
« Reply #16 on: September 09, 2014, 08:44:27 PM »
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The best way to alleviate potential curing problems with two part urethane resins mixed in small quantities is to mix them by weight and not by volume.  All Smooth-On product overview sheets list the A:B weight ratio even for those resins specifically designed to be mixed by volume.  Accurate electronic gram scales are cheap.  While most two-part resins are quite forgiving, thin-walled castings can take half of forever to fully cure if the mix ratio is skewed.

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Re: Need Help with Casting Resin Disaster
« Reply #17 on: September 10, 2014, 10:01:00 PM »
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I wipe out the excess and then just pour in properly mixed resin again.  It'll cure the remaining residue... though you will probably toss the part.

This has always worked for me too.
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Re: Need Help with Casting Resin Disaster
« Reply #18 on: September 10, 2014, 10:03:20 PM »
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"Some of my molds required more than a liter (quart+) of silicon"

Have you researched "glove molds" with a plaster backing mold? This can save allot on RTV rubber.
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Re: Need Help with Casting Resin Disaster
« Reply #19 on: September 10, 2014, 10:06:03 PM »
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" a slow setting mixture that should have a pot life of 30 minutes actually has a pot life of about seven or eight minutes, due to the heat generated by large volumes."

You can chill things in a refrigerator first? Have you tested this?
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Re: Need Help with Casting Resin Disaster
« Reply #20 on: September 10, 2014, 10:09:08 PM »
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^^^^Chill everything. The  molds and the casting resin.
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