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Jess8bit
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carboncactus
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No the heat gun trick is only for uncured epoxy laminates. Get a smackhead needle on eBay, lay the part down so the void is horizontal, then stab with a pin. When you get the courage, inject some gelcoat into the void. You could also use lacquer or epoxy. Let it overflow a bit and cure. You should have a tiny blob just poking out. Rub it with 1500 and polish.
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Jess8bit
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carboncactus (14/06/2013)
Your vacuum was good, as there is no pinholes. Unless vacuum was lost after gellationyeah, I'm really starting to consider this might have occured. Hard to know though. Do you think that if I warm up the border with a heat gun, the, the GC would stick to the resin again ? Does the gelcoat follow the shape of the part? If it does, then you just had a bridge. Inject it with some more GC50 next time you mix some up. Yes the GC follow the shape. But don't see how to "inject" it.
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carboncactus
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Your vacuum was good, as there is no pinholes. Unless vacuum was lost after gellation Does the gelcoat follow the shape of the part? If it does, then you just had a bridge. Inject it with some more GC50 next time you mix some up.
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Jess8bit
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fgayford (14/06/2013)
carboncactus (05/06/2013)
Looking at that last picture.......
Take a heat gun to the surface for a couple of minutes.
I have taken prepreg parts out of the oven and they looked a bit flakey. Like dry skin, sort of. Applied heat and the epoxy gelled a bit then fully cured, absorbing the dryness.I will second the heat gun attempt.FredDid you lose vacuum when making this part? Hi Fred, are you refering to the problem shown on my very last picture, or the former ones ?  Also, I can't be sure about losing the vaccum, apparently no, but how to be sure since the bag is clamped at both extremity (vac + feed lines) and there is no gauge on it anymore ? thank you 
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fgayford
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carboncactus (05/06/2013)
Looking at that last picture.......
Take a heat gun to the surface for a couple of minutes.
I have taken prepreg parts out of the oven and they looked a bit flakey. Like dry skin, sort of. Applied heat and the epoxy gelled a bit then fully cured, absorbing the dryness.I will second the heat gun attempt.FredDid you lose vacuum when making this part?
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Jess8bit
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Ok so now I have a good surface finish, At least, no bubbles anymore (I let the resin flow some time after it reaches the outlet connector, then clamp off the vac line, then the feed line) But, as you can see on the picture below, I'm facing a new problem, that occured during the trimming step. More precisely, in the sanding step that comes after the Dremel trimming. It looks like the gel coat is delaminating. It's only 4 or 5 spots like this, and only on the part perimeter. As if it did not like me sanding with the permagrit files. What could these defects be the symptoms of ? Is there a risk it propagates ?
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Jess8bit
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Ok, I see what you mean; thanks Warren
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wozza
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Your compressor may well be ok for a bonnet? just make sure you only spray a small area at a time, giving the compressor chance to keep up. What I am saying is if you over stretch the compressor you will get a difference in the thickness/texture of the gelcoat you are laying down. On something like a bonnet that will be noticeable in the surface finish once infused.
Carbon Copies Ltd
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Jess8bit
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mmm, 'm bit disappointed about my compressor, thought it was well dimensionned, but it has the following specs :input air : 350 liters/mn.
output air : 270 litres @ 7 bars.
Seems it is below the 12cfm required. Guess it won't go for a car bonnet :-/
my line is 10 meters long, and I have to check the diameter yet.
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