I was just wondering what is the cause of the tiny pinholes that appear after you sanddown your hotcouat. WOuld it be too much catalyst?? or Just dust. Someboards to get it a lilworse then others. I have checked the files here but didnt come up with much good info. I dont want to cover or put on future. WOuld like to get rid ofas many as possible… If possible
Damp air can be a factor. Whiping bubbles into the hot-coat batch (do not whip it – stir without breaking the surface). High possibility to holes in the lam coat – resin drain. Run a sealer coat over the lam coat – lam resin, as thin as you can get it with the squeegee. Make sure you are pushing the hot-coat resin down firm into the lam with your brush. Keep your grubby hands off the lam surface – use gloves it you have sweaty hands – keep it clean of any debris and especially water/sweat.
in my limited experience i have found my pinholes were usually caused by holes in lam also. It became especially apparent when doing darker color boards. my most nightmareish pinholes though were caused by large holes ( bubbles) in the blank after shaping. I was too lazy to fix, i thought the resin would fill adequatly but it did some crazy things when the resin kicked and made nasty holes. spackle does nicely for such things.
This can also be caused by a little too much moisture in the stringer. Or even some oil in the wood. Here is what I have done to fix the pin holes. A few years back Clark foam was making some real bad blanks. Every shop on the coast was having blow out problems. It did not show up in the lam coat but it started there. The glassers were going crazy. I got some of these boards to do ding repair on, and the guys ask me if I could do anything about the brown spots that were showing up in the foam for no reason that they could come up with. I took a pin vice and a small drill. I marked all of the pin holes that I could see with my poor old bad eyes, and then went to cheaters, real strong cheaters. I drilled all of the pin holes right into the foam. Then I used a water clear epoxy, put a dab of epoxy in the hole and then wiped it with a clean razer blade. I never got any of the boards back so I guess it workded good.
If your hotcoat kicks before all the solvent has a chance to escape, you could get “pock marks” or hole in the hotcoat. When it’s hot out, you gotta set it off slower.
Most of the pinholes I see are tiny bubbles in the lam. called “pinair” caused by taking to much resin off.It can be fixed if you catch it in time by squeegeeing the problem area with a bit of lam resin.Also to hot like STL said.Another bugger is tiny little wax globs that pop up at times.I guess thats why I like glossed boards,that extra coat will give a board a longer life…and nope you dont have to polish them if you don’t want to,it wil be even stronger. R.B.