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scherzoja · 24-06-2016, 19:33

I made a male plug today and something odd happened.

The mold for the plug is female. I waxed it with Partall paste #2 (about 10 coats), the sprayed Partall film #10.

Sprayed tooling gelcoat and let it setup until tacky.
Next, I layered in some CSM (with polyester resin). I think I had 3 layers in corners and 2 layers in the field

The part is a basin with dimensions of about 14" long, 12" tall, 5" wide at bottom, 9" wide at top.

A few hours later, the resin had kicked and I attempted to remove the plug from the mold. Came out pretty easy, but the release film/wax did not separate from the plug surface.

Usually, partall #10 will release from the plug surface or leave remnants on the plug, which wash off with water. But this time something went wrong.

The film residue covered most of the surfaces and was not water soluble. The material was waxy, like candle was. I don't think it was wax that precipitated out of the gelcoat because i've used gelcoat from this same can in the past and it contains no wax.

While spraying #10, I periodically sprayed a bit on my forearm to test spray pattern. That sample washed off quickly with water.

During cure, I noticed that the resin got hotter than it normally gets. Maybe I mixed too hot or built it up too quickly.

If partall #2 and/or Partall #10 get hot when resin kicks, will they turn into a waxy coating?

I tried several solvents (acetone, denature alcohol, mineral spirits, Naphtha, and lacquer thinner), but the only one that did much good on the wax was lacquer thinner.

I ended up destroying the female mold to get the plug out. In this instance, that was not a big deal because the female mold was intended to be sacrificial anyway, but the male plug is not and I would like to figure out what happened so when I make my part from the plug, it will pop off easily.

Any ideas what happened?

Thanks

FSMike · 24-06-2016, 20:36

Quote:

Originally Posted by scherzoja

-----

A few hours later, the resin had kicked and I attempted to remove the plug from the mold. Came out pretty easy -----

I ended up destroying the female mold to get the plug out.
-----

It "Came out pretty easy -----"
but
"I ended up destroying the female mold to get the plug out."

Those statements contradict each other. Which was it?

As for your problems with the release agent, the only things I can wonder about are the higher than normal temps, which I don't think would cause the problem, but also - how old is your supply of the release agent? You mentioned having used the same can of gel in the past? Is the release agent also dated? Other than that, you need to ask an expert, which I most definitely am not.

**minaret** · 24-06-2016, 22:15

Wax OR film, not both. If you spray a PVA release film on wax it often beads and doesn't provide a uniform surface, and it can also liqufy the wax again when it beads. It's like spraying a solvent on your wax job. 10 coats of Partall Paste #2 is a bit excessive as well.