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-   -   mold release options? (http://www.rcuniverse.com/forum/composites-fabrication-repair-97/11299719-mold-release-options.html)

thunderchief 11-16-2012 02:43 PM

mold release options?
 
What is a good mold release to use besides PVA? I have used PVA for years with wax and its great but I have been playing around with vacuum infusion and run into a problem. Many of the videos I have watched using the vacuum infusion process , have you using a light contact cement spray to hold the cloth in place while setting up the mold. The problem I have encountered is that if the cloth needs to be repositioned slightly, moving the cloth pulls up the PVA. Any ideas?
Glenn

invertmast 11-16-2012 04:10 PM

RE: mold release options?
 
Glenn,
I believe most of the guys using the resin infusion process, is using a semi permanent mold release system like Frekote.

wyowindworks 11-16-2012 04:18 PM

RE: mold release options?
 

Quote:

ORIGINAL: invertmast

Glenn,
I believe most of the guys using the resin infusion process, is using a semi permanent mold release system like Frekote.
Exactly! This allows the fabricator to use tacky spray to position the fabric witht he risk of tearing the PVA. Frekote FMS sealer and Frekote 770-nc works well with infusion and Airtech Airtac 2 (spray tack). You just need to test that Frekote is compatible with you mold surface and infusion resin. Resin Research infusion resins will stick to any semi-permanent. Adtech 820 will release just fine.


thunderchief 11-17-2012 05:02 AM

RE: mold release options?
 
Thanks guys, that may be the ticket. Do either of you know of a place to purchase the system. The places I deal with do not list it.
Glenn

wyowindworks 11-17-2012 08:59 AM

RE: mold release options?
 
Soller Composites sells the Frekote system. They stock both the sealer and the release. Don't buy the aerosal spray. Just buy the liquid. You can just wipe it on and wipe it off.

http://sollercomposites.com/composites/tools.html

invertmast 11-17-2012 03:50 PM

RE: mold release options?
 
Adam,
Is there any place state-side that sells the Air Tak 2 spray? Could a light dusting coat of 3m77 be used instead?

wyowindworks 11-17-2012 08:30 PM

RE: mold release options?
 
Quote:

ORIGINAL: invertmast

Adam,
Is there any place state-side that sells the Air Tak 2 spray? Could a light dusting coat of 3m77 be used instead?
Airtac 2 is available from Freeman Supply. If you google for "Airtac 2" you will see several other options.

If you mist a mold with 3M 77, lay in the fabric, and infuse you will end up with lots of little dots on the surface. This looks pretty ugly on naked carbon parts. This doesn't happen with Airtac 2.


Foxman 11-22-2012 06:28 PM

RE: mold release options?
 
I just use wax and it works everytime.
A tin lasts months and the surface finish is the same as the mould surface.
Maybe it works here because it's hot?
I spray the paint into the mould and use it as the gel coat.
My friend just waxes one time and still gets it to release easily but I don't think it's a good idea in case you miss a bit.
Jim

wyowindworks 11-22-2012 06:59 PM

RE: mold release options?
 

Quote:

ORIGINAL: Foxman

I just use wax and it works everytime.
A tin lasts months and the surface finish is the same as the mould surface.
Maybe it works here because it's hot?
I spray the paint into the mould and use it as the gel coat.
My friend just waxes one time and still gets it to release easily but I don't think it's a good idea in case you miss a bit.
Jim

What is the mold surface made from? What kind of layup resins are you using for the parts?


Foxman 12-17-2012 06:44 PM

RE: mold release options?
 
Sorry for the late reply.
I actually spray the plug after waxing with the same paint as I use on everything.
Then I give it a thick layer of resin and talcum powder and lay up over that.
The mould surface is just paint. It seems to work out ok and is very tough and durable. Never falls off.
I did have a bit of a bad surface on one mould recently because I left it outside for 30 minutes and it got really hot. So I rubbed it down and sprayed a thin layer of paint onto it, it came out really shiny.
The problem here in Thailand is the availability of decent mould making products so I have to use what I can.
I never use a Gel coat on the mould or the final product, just the paint which is a 2 pack polyurethane. This paint has a very fast hardener and is touch dry almost instantly.
You need to leave it overnight though for it to really harden.
The big advantage of a thin paint gel coat is that it doesn't ever crack like the old polyester types did and it saves weight. Plus it releases so easily.
The resin I use is just normal lay up epoxy resin. I have no specs on it other than the mix ratio but it seems to work ok. I used to work for Comp ARF and it is similar to theirs.
I guess it's a bit easier here because it is so hot that the resin remains thin and goes off quite well. Only got around 15 minutes though so I mix smallish quantities.
Jim


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