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carboncactus
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Sorry for digging up an old thread. This is OOA prepreg, Matthew, the pinholes are microscopic and evenly distributed throughout the whole part. There is nothing "going wrong", it's the nature of the prepreg. The only way it comes out with less pinholes is to have a perfect bag, perfect dwell, perfect ramp, vacuum on the whole day. Even then there will still be pinholes.
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Matthieu Libeert
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I think that any postprocess you'll do will take you some time...
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carboncactus
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matthieutje65 (27/01/2013)
why not doing te same with epoxy and a sponge or something? have no idea what results it might give  If you tape everything that is ok and just leave the places with pinholes, use a sponge with some epoxy resin, go over the pinholesI if the surface is flat, go over it with a hairdryer to level it all out, and let it cure. once cured give it some wetsanding and polish the part. Im working with out of autoclave prepreg, pinholes are evenly spread throughout the part and also they are very, very small. Microscopic even, some dont appear until you apply the clear coat, as they seem to get bigger the more coats it gets. It needs to be quick and easy, as I can't spend half the day on a part thats half a square metre. Time is money and all that.
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Matthieu Libeert
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Matthieu Libeert
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Group: Forum Members
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why not doing te same with epoxy and a sponge or something? have no idea what results it might give If you tape everything that is ok and just leave the places with pinholes, use a sponge with some epoxy resin, go over the pinholesI if the surface is flat, go over it with a hairdryer to level it all out, and let it cure.
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carboncactus
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Thanks for your replies. I have found this product: |
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brasco
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ack!! i made a mistake --sorry. this is for the finished product then damn now i feel like a bonehead !! i was thinking for the mold or the plug. sorry for the confusion guys --my mistake here.
CarbonFiberCreations
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Matthieu Libeert
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Ok Brasco but if you still want to keep a transparant 'coat', to be able to see the carbon this is impossible...
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brasco
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http://www.fibreglast.com/product/Glass_Microspheres_22/Fillersthey have a tutorial where they use this on a RC aircraft cowling. with such small size of the filler it SHOULD spread easy and sand easy. tips for filling "pinholes" as we call them in bondo -- is you can use a razor blade to wipe it in.then sand smooth you can wipe it is with a stick or other instrument, and sand. on bondo i have wiped it in the pinholes and then go back over with a cloth soaked in thinner, but not dripping wet,and wipe it and it will smooth over the pinholes and no sanding . this technique SHOULD work on resins. and yes OPEN the holes up with a tool of some sort. it makes filling them much easier
CarbonFiberCreations
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fgayford
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carboncactus (22/01/2013)
Hello, new here.
Been making some out of autoclave parts in prepreg, but I'm having problems with pinholes. They are very small. Lacquering and sanding time and time again doesn't seem to work. I believe they must be filled. Looking around the web, most products made specifically for the job seem to be American. Does anyone know how to do this efficiently? Needs to be cheap, quick and easy. It will need to be lacquered afterwards for UV protection.
ThanksPin holes will drive you to drink. Scuff and respraying doesn't fill these holes. You have to abrade these holes or they will just repel your clear coat. I have tried a needle point dremel bit and just touch the holes and then mixing clear coat and waiting till it starts to kick and then filling the holes one at a time with a tooth pick. It's bush league but fills then like a filler. Once I have them all filled proud I wet block sand flat and then the clear will lay down nicely when sprayed. Here is what I think is going on in regard to the pinholes seeming to repel clear coat. When epoxy cures a film comes up to the surface. I think it is called alum blush. It is a waxey material that gets removed when we scuff and prime wash before spraying clear. But! you don't remove it from the pin holes by this action. Therefore the repelling is as if it has wax in the bottom of the pin hole. I just today ordered a thing called a sanding pen which auto refinishers use. I hope this will be fine enough to get into these pin holes.
Hope this helps.
Fred
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