PVA mold release / epoxy

[Buju]

haven't ever used it, will it release epoxy resin ok?

[CaptPatrick]

Mark,

PVA will release just about anything except water based resins...

Use a jam gun with the pressure cranked up to about 90 PSI and a wide fan. The material needs to be very well atomized... Apply about 3 or 4 coats 15 minutes apart.

PVA is water soluble, so when removing the part from the mold, use water like you would use compressed air for normal part removal

If your mold is well seasoned, 4 coats will be fine. If it's a new mold use 5 to 6 coats. Allow the final coat to cure for at least an hour if the humidity is below 80%. 2 hours if above 80%.

Clean your gun with warm soapy water.

[Buju]

Thanks for the quick and informative reply Capt.
The insight is highly instrumemntal in preventing "prototypes"...

[CaptPatrick]

Your mold must still be pretty slick, but waxes will cause the PVA to want to bead and draw back. If you've waxed the mold surface, give it a good warm soapy water wash down with a soft rag before applying the PVA.

Make your first two coats just a mist so the following coats have something to grip to.

You might want to experiment with another object or objects to see how the material lays down and reacts. If you're not happy with the application, just wash it off and go at again...

Try peeling the dried film off. You'll see how delicate the film is.