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Fix to tacky molds

I stumbled upon this site:
which gives tips on using the casting resin we've been using for potting our keychain.

Bullet Points:

  • "Casting resin's curing process is caused when heat is generated by the chemical reaction that takes place when catalyst is added to casting resin."
  •  thicker the layer, less catalyst is needed; the thinner the layer, more catalyst is needed.
  • The biggest disadvantage to flexible molds is that castings come out tacky and wavy because heat from the resin when curing dissipates quickly through the rubber molds."  <-- this explains why our rubber mold came out tacky and wavy! It's cool finding information which supports your experimental findings
  • best molds are made from HDPE (high density polyEthylene plastic).  This is the type of mold which the catalyst amounts were developped for on the label.  Other molds will require either more heat to be applied during the curing process (place in oven ~100F) or doubling the recommended catalyst to intensify the chemical heat. 
  • If the cast comes out tacky then place in the oven on low heat until it's completely dry.

1) Placed the completed mold from last night in the oven to let it completely dry.  Hopefully this will make it completely tack free.

2) Potted a test mold using 30 drops of resin instead of the typical 15.  I also placed it under the heat of our incandescent lamp in the living room.  In less then 3 hours the mold was solid but still a bit tacky. 

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