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Old Jan 28, 2013, 07:49 AM
I am actually really slow
SlowBarless's Avatar
Brisbane
Joined Jun 2008
961 Posts
Hmm, seems to be alot of conflicting ideas here.. This is just what I think.

1. PVA shouldnt be frowned upon as a 'beginners' tool.

2. Ive never had trouble with epoxy parts releasing from epoxy moulds with just wax as the release. I do put down atleast 2 coats of wax though, even on seasoned moulds. Ive found however, it's easier and less time consuming to lay down one coat of wax, then just PVA over the top. The release is nicer then several coats of wax. The moulds can be sperated
easilly by hand! I should say that If I was working with larger cnc'd moulds that weren't so finicky, then I wouldnt be using PVA at all.

3. Wax is the only thing I would use for mould production. PVA has a considerable thickness to it. Using it to produce moulds can thicken your seam lines and losen the tight mould tolerances you've worked so hard to achieve!

A trick to having successfull releases using just wax for epoxy parts/epoxy moulds is to ensure that you have post cured the moulds/plug atleast 10degrees C higher then the maximum temp the moulds will see while being used. All my moulds are post cured up to 80Degrees C. This way I know they wont begin to soften at their maxiumum production temp of 60Degrees. As soon as you push a resin system close or past its HDT the wax will do you nothing for the release, and the part will stick. Every plug or mould should spend some time under temperature before its used.
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Old Jan 28, 2013, 10:26 AM
Just fly it!
wyowindworks's Avatar
Cody, WY
Joined Nov 2007
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When I used wax & PVA, I would wax once every 4 or 5 cycles but use PVA every time. As mentioned earlier, the release is so much easier and the molds are easier to keep clean. The release of semi-permanents is easier yet.
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Old Feb 10, 2013, 10:53 PM
Entropy is happening!
Jim.Thompson's Avatar
Bellingen NSW Australia
Joined Aug 2008
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Good results!

I had very good results this morning spraying the PVA over the talc dusted waxed mould and plug.

Details on post #541 of my build thread here:

http://www.rcgroups.com/forums/showt...339865&page=37

I'm very pleased with the results!
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Old Feb 10, 2013, 11:02 PM
Entropy is happening!
Jim.Thompson's Avatar
Bellingen NSW Australia
Joined Aug 2008
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Quote:
Originally Posted by SlowBarless View Post
.................................

A trick to having successfull releases using just wax for epoxy parts/epoxy moulds is to ensure that you have post cured the moulds/plug atleast 10degrees C higher then the maximum temp the moulds will see while being used. All my moulds are post cured up to 80Degrees C. This way I know they wont begin to soften at their maxiumum production temp of 60Degrees. As soon as you push a resin system close or past its HDT the wax will do you nothing for the release, and the part will stick. Every plug or mould should spend some time under temperature before its used.
Excellent point. The entire post is a valuable one FlyB!
(Makes mental note to remember this, bookmark the page etc..).

I'm thinking one of us, (maybe the thread oringinator "Ne-Aero"?), might like to collate all the salient points that arise and are expressed in this thread, and post them in a final or ongoing sort of "How to do" brief tutorial.
I'll give it some time, and if no one volunteers or objects to me doing it, I will initiate it.

From my point of view, it has been, and continues to be, an excellent thread.
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Old Feb 11, 2013, 01:34 AM
I am actually really slow
SlowBarless's Avatar
Brisbane
Joined Jun 2008
961 Posts
Jim, I was looking at the photos in your link (#540) Thats alot of streaks from the sponge! Like you said probably due to the wipes disturbing the talc.

Ill wack up some photos of how my moulds come out when covered in PVA tonight.
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Old Feb 14, 2013, 04:18 AM
Entropy is happening!
Jim.Thompson's Avatar
Bellingen NSW Australia
Joined Aug 2008
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Difficult release.

Quote:
Originally Posted by wyowindworks View Post
If there is no paint then epoxy on epoxy can be a stubborn release even on a seasoned mold.
Yes Adam, I found that out today first hand.
My new plank wings layed up with wax only and no paint were difficult to release!

They came out with minor damage. However, the lesson is well learnt.
Next time, I'll prime the moulds at least, or go back to PVA untill they are very well seasoned.
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Old Feb 14, 2013, 06:25 AM
I am actually really slow
SlowBarless's Avatar
Brisbane
Joined Jun 2008
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Got some photos of my PVA application and the finish on the complete part.

Why does paint make a difference with the release? I haven't really noticed a difference to be honest, but I haven't painted many moulds..




Ben
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Old Feb 14, 2013, 05:15 PM
Entropy is happening!
Jim.Thompson's Avatar
Bellingen NSW Australia
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That's a beautiful piece of work Ben!

Paint between waxed mould and part? I'm guessing that is simply provided another barrier between them that further inhibits chemical bonding of any vagrant molecules.

The "Why Moulds Stick" article explains it to some degree, even though it doesn't directly mention paint.

Jim.
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Old Feb 15, 2013, 04:50 AM
I am actually really slow
SlowBarless's Avatar
Brisbane
Joined Jun 2008
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Thanks Jim, here's another one that has a PVA finish



Ill have to read the why moulds stick thread. Ive never really had an issue with anything sticking though. The only time I had something stick real bad was when I neglected to post cure the plug and the plug softened while I was postcuring the moulds (Silly me).

I suppose another topic all together is the quality of the wax that you're using. Im sure there's differences between say what I use and what you use yourself Jim. I have some old wax called PLP10, Its really amazing stuff despite being 20 years old. I dont think its available anymore either unfortunately
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Old Feb 15, 2013, 01:51 PM
Entropy is happening!
Jim.Thompson's Avatar
Bellingen NSW Australia
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Quote:
Originally Posted by .......................[I
I have some old wax called PLP10, Its really amazing stuff despite being 20 years old. I dont think its available anymore either unfortunately[/I]
That's what I'm using too Ben!

I heard the same, it's no longer available. My local fibreglasser professional who supplied it tells me he will be getting in a wax to replace it. I don't know what it is yet. He had a 20 litre bucket of it when I got a 1/2 litre of so from him about 6 months ago.

Jim.
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Old Feb 15, 2013, 08:21 PM
I am actually really slow
SlowBarless's Avatar
Brisbane
Joined Jun 2008
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Quote:
Originally Posted by Jim.Thompson View Post
That's what I'm using too Ben!

I heard the same, it's no longer available. My local fibreglasser professional who supplied it tells me he will be getting in a wax to replace it. I don't know what it is yet. He had a 20 litre bucket of it when I got a 1/2 litre of so from him about 6 months ago.

Jim.
I was told the factory burnt down Not looking forward to the day I run out of it and have to reseason all my moulds! If you ever manage to find some more please let me know!
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Old Feb 15, 2013, 09:27 PM
Entropy is happening!
Jim.Thompson's Avatar
Bellingen NSW Australia
Joined Aug 2008
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Quote:
Originally Posted by SlowBarless View Post
I was told the factory burnt down Not looking forward to the day I run out of it and have to reseason all my moulds! If you ever manage to find some more please let me know!
Not likely to happen I think.

The most commonly recommended wax on these forums seems to be TR wax. There are two, I think the high temp one is the one to use, but not sure.
I'll be asking the builders that I know who are using it with success (which variety I mean).
Also as I said before, my local (less than a hours drive away from where I live) manufacturers have to get in a good replacement in bulk. So, there will be the option that they choose.
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Old Feb 15, 2013, 11:21 PM
Life begins at transition
Australia, VIC, Sale
Joined May 2007
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TR-102 works great for wax-only, but I suspect it's got silicone in it, as it's almost impossible to paint/PVA.
108 works a treat with PVA; never tried it wax-only.

Haven't touched 104 (hi-temp), it'd be interesting to see how it goes compared to the two I use. I just can't justify yet another tin of wax lying around!
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Old Feb 16, 2013, 12:01 AM
Entropy is happening!
Jim.Thompson's Avatar
Bellingen NSW Australia
Joined Aug 2008
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Thanks for that info Odysis.
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