Some more parts, but in need of advice

General Composites Discussions Showcase
#1

Overall a LOT better then my last one…but why the pinholes/voids???

here is what i’ve been doing.

polyester with air dry additive, 2-3 layers of carbon, then a single layer of ~1.5 oz glass, then teflon/nylon(can’t remember which) coated release ply, then the resin flow media.

the bags hold their vacuum

I mix the resin then let it sit for a while to let the air bubbles rise (despite this there are still miniscule bubbles that will never rise to the top) any tips for this aswell would be appreciated!

Obviously there is a little bridging near sharp creases, and the bubbles tend to collect along these paths. I pull vacuum many times and try to work the carbon into the angles as best as I can, before letting the resin in, but still it happens. suggestions for eliminating bubbles or the bridging?

any tips?
Thanks

#2

here is another picture

#3

Try pouring for one cup to another in a long, thin stream to help mix and pop bubbles.

#4

Are you using a resin system made for infusion process? If not and the resin is too thick, then you may well be getting all sorts of problems.

#5

The resin is not specifically made for infusion to my knowledge… but it is nice and thin, the entire parts infused in about 10 minutes at most…

#6

I thought that when I last did this I got more bubbles, I will have to try once again, thanks.

#7

up to about a quart, I like to mix epoxy in zip lock bags… put the bag in a cup, roll the top of the bag over the cup lip, add resin & hardner, zip bag 90%, remove from cup, work the last air out the open zip end, close it up and knead for a couple minutes… works very well. For wet lay up, cut off a corner and you have a great resin dispenser. For infusion, dump the bag in a cup, or you risk the bag plugging the resin hose.

#8

bloody good idea!

as long as the resin system doesn’t eat the plastic :wink: ie: too much styrene!

Another idea is a hard one. vacuum bell jar (or really, any sort of strong material). Stick the mixed resin in there, let the vacuum degas it, and it kills the bubbles.

#9

I think that is why he said for epoxy that is how he mixes the resin components. PER would eat a hole in thin plastic.

#10

from what i understand RC51_20 … ah heck… read up on www.racingcomposites.net the user “Admin” there did a write up about this exact same problem and how to solve it. I don’t think it’s your resin, it is how you are doing the lay up with the first coat of resin into the mold… bad idea i think. Just wet each layer, squeegy off all the excess resin from each layer, then vacuum bag it. spray your finished part with clear coat or maybe PER gel clear gel coat. Or perhaps spray clear gel coat into the mold, let it get past B-stage to where it is almost cured, then do the lay up with your resin and carbon fiber/ f/g… whatever laminant. Try to find the thread on that website, i think that will help you with this air bubble issue.

I like those chain guards… very cool idea.

#11

Dang, Thanks “Intrepidman” for that idea! I have been doing pavers around the home and have 20 gallons of PER lam resin getting old!

I’ll use your idea of the zip lock baggie to apply a runner between them and then add a little more sand to lock and prevent weeds growing thru them!

#12

I’m infusing though, that is why I’m confused why the bubbles don’t get removed as the resin front travels?!