I wet layup carbon fiber but there’s always bubble trap after I pull it off from the mold, what do you guys do to fix the bubble traps? any other method I can do other than fill each bubble trap with resin?(very time consuming)
Where are the bubbles. On the mold side?
What resin are you using?
Are you vacuum bagging, or just laying wet fibers down, and letting it cure?
With out that info, I can say 2 things.
1: vacuum degas your resin before using it.
2: do vacuum infusion instead
3: make sure you wet out the layers completely, and use enough, and the right bagging materials (part, peelply/perforated release film, bleader, breather, bag.)
4: do vacuum infusion.
5: if no vacuum bag is used, i don’t think there IS a way to get rid of bubbles minus degasing the resin before you brush it on.
if your just open molding the only suggestion I can give you is sand all the bubble areas down to the carbon and clear coat the part. I have been doing that if I have had any problem areas.
Are you using chopped strand mat, fiberglass cloth, carbon fiber, ? What style of cloth are you using? Are you using any peel ply? Are you vacuum bagging the mold? What vacuum pressure are you getting on the vac gauge? Are you using breather fabric?
what inside diameter is your vacuum hose?
This is an open mold wet layup with plain weave carbon cloth back up by plain weave 6oz fiberglass cloth. There’s not a whole lot of bubbles but there’s bubbles here and there. Is there a technic for open mold carbon wet layup?
If your want air free bubble free parts you should vacuum bag the molds. 
yeah but then you have to do what most low line chinese companies do. Make the part in glass then overlay it with carbon
wax the mold,
spray in the gel coat;
let it get past B stage to where it won’t come off on your finger but is still tacky to the touch; now lay in your carbon fiber taking your time to work it into every corner so there is no bridging… use a squeegy and that will help. Now wet out that layer with resin and drop in a layer of fiberglass cloth. wet again and lay in more cloth… get all the bridging taken care of prior to bagging or at least try your best. Once you have as much cloth as you need into the mold, now add a single layer of peel ply, cut it into small pieces so the peel ply doesn’t want to bridge. Now add some white breather fabric on top of all that. Bag the mold and run full vacuum to it.
If you are using an mekp hardener in the resin don’t do more than two or three layers of fiberglass cloth at a time.
isn’t it more work than just vacuum bagging?
it is but you really cant screw that up as far as air bubbles go
Have you tried different materials, or have your problems always been with the same stuff?
I can make perfectly glossy and pinhole-free parts by wet lay-up. All depends on the resin, fabric, and most importantly the application technique.
what resin are you using? and what technique do you do? if you don’t mind share.
the first half of the job is to make sure the carbon fiber doesnt bridge. you can use a spray adhesive to stick the cloth in the mold so it won’t move. because epoxy dissolves spray adhesive, if you apply the resin and start brushing it , it may move, here’s a sure way of not moving around. wet the carbon properly with lots of resin, and add your fiberglass layers. then use the brush with force, to wet out all the layers while moving air (and excess resin) towards the outside borders of the part. A good tool is a teflon roller, but in pars with lots of curves you may not be able to use it. and the danger areas usually are the edges where the mold rolls up.
Getting rid of the air holes has to be one of the most difficult and frequent problems for most people, what is your expert advice on resin, fabric and technique?
spraying gel coat you shouldn’t get pin holes unless you have dirt/dust on the mold surface or some other contaminate.
If i do an epoxy surface coat onto the mold surface, I use a butane torch set on low to remove the gas/air bubbles after the surface coat is brushed on.
Sorry, I should have been more clear, I meant as per the thread subject - air bubbles inbetween the clear gelcoat and the CF. I bought some off-the-shelf flat sheet ages ago and even that had some in it.
I’ll have to do a few wet lay ups that way using PER gel coat and VER resin. The guy I share the shop with did a lay up this way and it came out very nice one time, another time he had some bubbles in the gel coat itself.