Hi all, when I make a carbon part should i wax the mould PVA it or both like I have been told? Thanks!
Depends on the mold, PVA is for bad molds, wax gives a much better surface finish.
Can I use just wax on its own?
If you have a mold release wax, yes, but only on good molds (at least polished to a glossy finish)
5-7 layers for the first product, read the instructions for time in between layers and how long to wait after last layer (mostly 15 minutes and 12-24 hours)
If you have molds wich have a sanded finish, do not bother to use wax, just go with te PVA. The wax otherwise will prevent the PVA from covering the entire part, leaving fisheyes everywhere.
PVA is no good, use semi-perminent sealers and release
+1
When I first used Freekote I was amazed how nice it releases when compared to the other mold releases like wax and pva.
Grab the PVA, throw it in a dumpster.
Then use only wax or a liquid semi-permanent release agent.
i would love to do that.dont you need to use pva on new moulds?i have a set im working with now that have a few cure cycles on them.is it safe to switch to semi perm?i have the sealer and the release.
Any names of semi-permanent products that I could get in the UK? Just wanted to do a search.
Frekote, Ferro FS10, TR, Cirex (Sicomin).
As for PVA: Very useful for crappy tooling, or materials that cannot withstand styrene (Gibco Flexmold, acrylic paint) and where you want to be extra-extra sure the thing pops off. (for instance when splashing the bodywork of the last original Porsche 907 that is insured for 1,5 million dollars.)
i had a mould stick when i switched to semi perm.the only thing i didnt have was the sealer.i was told by fiberglass supply that i didnt need the sealer.anyway the mould stuck big time.so this is why im a bit scared to try it again.so now i have the sealer to use with the semi perm.so i figure i will need to try it again.
Something must have been wrong. A properly applied semi-perm will allow parts to slip right off.
You should always use a sealer. also multiple coats of release should be applied first time, usually 3+ depending on the type, waiting the recommended time between coats. Also, you must wait for it to fully cure or else it will act as a adhesive, chemically bonding your part to the mold. Most will be cured with in 30-60 minutes. But as always follow the instructions exactly. And make sure to always put the lid on very tight, air will degrade the release quickly without you knowing it. Lastly, before making a part, do a tape test with 3/4" 3m masking tape, this is a good indicator of how well it is coated with release. Good luck.
thanks for the advice.i did follow the mfg directions.i did 7 coats.i just didnt have the sealer.they also list a cleaner on the can.fiberglass supply said to use a common cleaner available from a hardware store.i forgot what it was.the tape test should be a good indicator to see how well its releasing.
I had the same problem with a Frekote semi perm.
The mould I had was basicly crap. At that time I knew about nothing, but the expert where I could build my boat said Frekote would do a perfect job. I wanted to go the PVA route. (I planned on laying up a first layer of peelply first, as the boat needed fairing and finishing anyhow).
I wished I was more stubborn at the time…
this stuff i have is chemlease.the mould was new.it had 2 cure cycles on it.i think im going to try it on an older mould that has been reproduced.so there is no risk.
there have been times i wished i had used pva myself.its hard to go away from something that works.its just such a killer when i have a mould stick.im out time and money.i have had great results using the semi perm on some aluminum moulds i have.the stuff works great.i just need to figure it out on my frp moulds.
Is it possible to use semi-permanent release AND wax on a brand new mold, just to make sure it didn’t get screwed up? Following that I would plan to continue with only semi-perm. Bad idea?
Yes, that is possible.
We use Ferro FS10 cleaner and sealer, to seal a new mould or plug surface, (semiperm), then use regular Meguiars Mirror Glaze 87 or similar to wax the mould.
I have had a lot of negative comments on this, but it has never let me down. Green molds can be a real pain sometimes.
PVA is great for crappy molds, but surface quality leaves a lot to be desired.
sorry but i am new to all this. Whats sealer?
its a modified semi permanent release that fills in the micro purosity of your tool. You apply it to the tool before apply your release. You must seal a mold when it is new or has been stripped and polished.