tommyboy1229

All to often when I lay up a part (wet lay) even if I roll it out very well I seem to end up with an air bubble or a few. When I vacuum bag the part the finish looks great inside and out and it is of course lighter but upon close inspection there are many pinholes. This is noticeable before priming. I am pulling about 20-25 inches of vacuum, is this to much? I am laying up wings, fins, fuses etc.

Thanks,
Tom

Darrinc

My Feedback: (5)

I have found a couple of reasons for pinholes. (I'm sure there are many more) Mainly that the bleed was not controlled, so the finished layup is a little too dry, the other is the resin system. People say that Pro Set will bubble at anything over 13 inches. Why, I don't know, but it does!

If you have a vacuum system, you can make a vacuum chamber and boil out the air bubbles in the resin before laying up. Thats a little radical and takes a special touch.

For a experiment, I would layup the cloth on thin plastic, then put another layer of plastic on top of the layup and squeegee, you should see any areas that are dry. Pull the plastic and place on your prep'ed surface and put waxed paper over top ( the waxed paper must extend past the layup), then bag as normal and pull full vac.

Let me know how that turns out, we can work from there.

Ed Smith

Do not feel too bad. I have been molding and vacuum bagging for years. I always get pinholes. I gues that is why "Pinhole filler" is sold.
The only cure I know of is to apply a gelcoat before the layup. The pinholes will still be in the layup but covered by the gelcoat.

If you find a practical cure then please educate us all

Ed s

buttuh

If you're using a bleedable release ply then your pin hole problem is from sucking too much resin out of the layup. You could apply some gel coat first or lower your vacuum. If you are not using a perforated peel ply then your problem is from trapping in air bubbles. It also helps to apply resin to the mold first then lay down your reinforcement.

Evan

boater

My Feedback: (2)

Synkloid's exterior spackle has a marked resemblence to the expensive hobby stuff. Get the EXTERIOR stuff, it is basically spackle, but turpentine solvent instead of water solvent. Rudy