Talk Composites - The Forum for Advanced Composites

removing/stopping defects and strengthen/reinforcement of a part

http://www.talkcomposites.com/Topic563.aspx

By ARSOUILLERB26 - 2/7/2012 1:37:12 PM

Hello everybody, I contact you for a few problems about a carbon kevlar tray I ve made

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My first problem is for me a real nightmare: tiny bubbles:







I eliminated a lot them by using resin infusion (but not all of them) and using bristle roller but to have a perfect finish, I don't see any other way than to varnish (if there is an other possibility please let me know)

So I would like to know how to make this perfectly, what products do you use (I didn't see them on your shop) and the application method to have a perfect gloss finish .





For my second question, I've done this tray with 2 layers of carbon kevlar and with 2 of red traced carbon ^^ in the middle but it's too flexible specially on the 
flat part.
















I would like to know if it's possible for a next one to make it more stiff by putting a kevlar cross in the middle of the reinforcement layers Throughout the flat part and if it will be (for just one kevlar layer) visible on the exterior of the tray?

Or if is it possible to make the tray for stiff by an other way (curing?) cheaper than to put  2 or 3 more carbon reinforcement layers.





By advance, thank you for all your answers  Smile
By Matt (Staff) - 3/5/2012 1:44:02 PM

Do you think it's possible it came from the mould surface? Not enough smooth which let place for air between the mould and the carbone layer?


I don't think so. If your vacuum pump has pulled all the air out of the bag any gaps (even tiny gaps due to the texture of the surface) will simply be vacuum (i.e. no air), just space into which the resin can flow.

And excuse me Matt for repeating my answer but english is not my main language (so I hope you haven't difficulties to understand me ^^) so, during my infusion, if I see any bubbles (moving for extraction), I let the both vaccum and resin line open until I don't see them any more. It doesn't matter the time it take. After I close the both clamp like normal... Is it right? (I couldn't use that technic with sonic infusion core for the next one, it's just by curiosity)


Correct, you can keep the whole 'cycle' running for as long as you want to flush it through. We'd always hope to not need to do much of this because it wastes resin but if it helps to troubleshoot the cause of your problem then it's worth doing. Remember to close the resin feed line off first in this situation and let the bag pull down a bit before clamping off the vac line, otherwise you will have too much resin in the laminate.

I don't see any reason why this wouldn't work with Soric either.

--Matt