Mould release agents.

[daleh007]

I am just about to embark on potting my coils and was wondering what the group uses for a mould release agent. In Hugh's plans he says to use "wax polish". Is this automotive "paste wax"?

Daleh

[stop4stuff]

hi Daleh

In the past, i've successfully used ordinary furniture beeswax (solid stuff in a tin) as a release agent for making grp molds and grp replicas of auto panels... worked really well for me.

paul

[cevonk]

Probably the most commonly used commercial mold release agent is PVA, Poly-vinyl Alcohol.

Good comments on how to use and why molds stick are here:

http://winshipmodels.tripod.com/pva_mold_release.htm

Random Google search for "PVA supplier" resulted in this hit:

http://www.fiberglasssupply.com/Product_Catalog/Release_Agents/release_agents.html

Their "Partall Film # 10" is PVA, and costs $13.33 for a gallon, or $3.13 for a pint.

[richhagen]

I've only done this a few times.  The first time I used wax from a new toilet ring,(I switched to using gaskets in the apartments, so I have a few of these lying around) It worked fine when applied liberally.  Lately, after reading it here somewhere, I've simply used a liberal coating of axil grease.  That also worked fine and is probably easier for me to work with.  Probably anything that the resin won't stick to that can be smoothed over the mold will work.  I guess if you were looking for fine detail in the mold, you might need a less viscous or thinner layer of release agent.  Hope this helps, Rich Hagen

[troy]

I think the Dans even used a good coat of liberally applied crayons to some of their molds, so it appears that any liberally applied wax or grease will work OK.

That does not guarentee they will work as well as using proper PVA mold release agent...

Good luck and have fun!

troy

[Chagrin]

He's probably referring to something like "Johnson's Paste Wax". You can find this with the mops and brooms at your local Wal-Mart. Quit economical as I remember.

[nothing to lose]

About anything actually works depending what the mold is for I geuss.

For casting metals in rubber or metal molds I use a graphite, but then agian I am going for detail in the castings too and also have alot of heat!

When we did some fiberglass moldings for custom car parts we used to wax the molds with normal paist wax and then press the wet glass into the mold and press.

Sometimes we even painted the waxed molds, then molded the fiberglass parts. Was nice, the parts came out already painted and we did not have to worry about runs in the paint since any we got were on the fiberglass side, not the wax side.

 Course we were working with molds that were fine finished for a smooth ready to use body part.

 Using a rough mold you might need to fill scratches and voids, etc.. better with a wax to keep the part from sticking.