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Resin casting mold release

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  • Member since
    June 2021
Resin casting mold release
Posted by rocketman2000 on Wednesday, August 25, 2021 7:47 AM

I was setting up a mold for resin cast and found I was out of talcum powder. Went to pharmacies in area, with no luck.  found some online, but it will take a week.  Fell back to thinned Vasoline, but I really hate to use it.

That got me wondering, what do other people use as a release?  I know you can get by in most cases, but with a complicated pattern I prefer not to take a chance.

 

Don Stauffer in Minnesota

  • Member since
    March 2003
  • From: Towson MD
Posted by gregbale on Wednesday, August 25, 2021 7:58 AM

I've always used silicone spray. (If you use silicone first, then talc, it will give your castings a nice matte finish.)

I think the last time, I found the spray on sale at Staples, of all places.

Greg

George Lewis:

"Every time you correct me on my grammar I love you a little fewer."
 
  • Member since
    September 2006
  • From: Bethlehem PA
Posted by the Baron on Wednesday, August 25, 2021 11:51 AM

I don't cast with resin, but with white metal.  I use talcum powder as a release agent with my silicon rubber molds.  I'm surprised that you couldn't find any in local drug stores, but I suppose it reflects ongoing logistical disruptions caused by the lockdowns.  Did you try grocery stores, too?  They might have had it in their health & beauty aisles.

With metal molds, I use soot to lubricate them.  I hold the mold halves over a candle flame and let it deposit soot in the cavity.  Of course, you can't do that with rubber molds Wink

The bigger the government, the smaller the citizen.

 

 

  • Member since
    August 2021
Posted by goldhammer88 on Wednesday, August 25, 2021 9:27 PM

Most all talc powders have been pulled because if the lawsuit on cancer in women.  Try looking for medicated powder, such as Gold Bond or Equate.  Wonder if foot powder would work?

  • Member since
    April 2013
Posted by KnightTemplar5150 on Thursday, August 26, 2021 5:25 AM

If your preferred release is unavailable, an old trick is to use nonstick cooking spray. The oils in those aerosol cans is inert and food-safe, so it won't attack the mold or interact with the resin as it sets up. Works well with both latex and silicone rubbers, plus it cleans up with dish soap and water.

Caveats - some brands tend to foam up, so test things before you commit to mixing your resin for the pour.  Extra gas being trapped in the mold can be a nightmare. 

Resin castings done this way will sometimes have a bit of a greasy feel to them because of the oil, but a light wash takes care of things quickly.

 

  • Member since
    June 2021
Posted by rocketman2000 on Thursday, August 26, 2021 9:00 AM

the Baron

I don't cast with resin, but with white metal.  I use talcum powder as a release agent with my silicon rubber molds.  I'm surprised that you couldn't find any in local drug stores, but I suppose it reflects ongoing logistical disruptions caused by the lockdowns.  Did you try grocery stores, too?  They might have had it in their health & beauty aisles.

Wink

 

No, the issue is cancer scare.  Turns out talc has asbestos fibers in it.  It is no longer used for babies.  I did find on line a brand of after-shave product that is still talcum, but I will have to wait a week or so to get it, and wanted to get casting finished before then.  Used wax instead.  Forgot about silicon spray.  I'll use that before the actual resin pour.

 

Don Stauffer in Minnesota

  • Member since
    August 2019
  • From: Central Oregon
Posted by HooYah Deep Sea on Saturday, August 28, 2021 10:25 AM

When I was making bitts and chocks out of two-part epoxy, I used soldering flux as the release agent. It seemed to work fine. You just have to clean the part afterwards, but I'd think you would have to do that anyway with whatever you use.

"Why do I do this? Because the money's good, the scenery changes and they let me use explosives, okay?"

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