Do Pinholes Leak?

Aloha,Yes I have looked up “pinholes” in the archives . Lots of info there . But no one asked that question. Do little pinholes in the sanded hotcoat lead to leaks … You know . “water in leaks” I will do a gloss coat on my new board if I need to. But I’d rather put the fins in and ride it… Thanks so much for any answer I can get … Mahalo to all… Don J.

Suck on it and find out. It’s impossible to tell if a pin holes is due to gassing from the blank, bubbles n the resin,or not sufficiently wetted out lam. While some pin holes may leak after some flexing, the best way to determine if a pin hole is going to leak today is suck on it.

Personally, I use suction cups, which can be had at a hardware store for about $2.

If you are creative, you can use the plunger for your toilet, but I’d recommend not kissing it with your lips.

But generally, yes, they leak when warm/hot or flexed, so seal it. Strong squeegee application of resin usually does the trick, but sometimes a needle helps. Some guys just lay some styrene into the pinhole area, then gloss over.

Superglue works also.

Thanks for the reply . Wont the holes just fill in if I do another . Thin Coat Gloss/Hotcoat ? I think They were from overmixing the hotcoat resin . I did really whip it up. I read a lot of reasons in the archives as to how pinholes can happen . It still wasn’t clear as to how to fix them however . I am gonna try another thin coat… any suggestions as to the mix .surfacing agent /hardener?? am going to mix up 1/2 quart for it . That should be more than enough but I’d rather have too much and have it run off the board than to have too little.

My experience and expectation is that eventually, they do leak and the foam at the pinhole yellows. Your gloss coat may or may not seal them, it depends on how much you thin it, how much you stir it up, how long it takes to go off, and so on.

Now that I use UV resin, I thin finish coats about 10 percent with styrene, mix well, let it stand a couple minutes, brush it out in my darkened garage (just a pair of 40inch fluorescents running), then wait ten minutes or so for the wax to rise and any bubbles to pop, before I open the garage door and drag the rack and board outside. Hopefully into bright 80 degree sunshine. Goes off snap/bang, nice wax rise and smooth. If raining or may drizzle, just open the garage door and set the board parallel to the street, enough UV will hit it to go off, just not as fast.

Thanks for the reply. I had an epoxy board worked on once . They changed the fin box. I was told by the glasser that he had to put the board outside to warm up some then lay in the epoxy and bring it in to the A/C which “the cooling” caused it to suck in the epoxy resin . otherwise when he did it the regular way the heating up epoxy going off caused offgassing and the epoxy to bubble … Pinholes…Temp. really does matter .

    I layed these hotcoats in the cold .. outside.. then brought them to a warm room. Maybe that contributed to the pinholes .

Gloss coat may or may not seal the pinholes. If the cause is from dry lam, prolly not. If the cause is aerated hot, possibly, but not 100%.

You gotta take care of the problem…and checking EACH pinbubble spot is a necessity.

Each Pinhole ? See how many there are ?? This is the worst spot . Each white dot is a pinhole with dust in it . And there are more . I really don’t think their all the way thru . I washed the board with water and t didn’t seem to bleed water out . If I lay another coat on should I use more or less surf. agent ? 1% or 2% ?

Thanks for you help This thing is almost done … I thought . I really can’t wait to try it…D.J.

well its your board so do whatever you want but ive spent days filling pinholes that went through to the foam,i use a needle…sometime you might have to fill it many times cause it could just keep sucking the drops in,i listened to advice once and used small needles to hold down a stencil while painting…well 75% of the holes in the foan ended up as being pinholes in the hotcoat…wont try that again.

Polyester resin breaths,and is not waterproof ,it is only water resistant.

So in the long run it really doesn’t matter.Herb

Last spring '04 I watched Dave Collignon of Fiberglass Hawaii Santa Cruz fame, glass a 5’8" board with UV activated resin and E glass. Soaking the fiber, he proceeded to squeegee out so lightly it looked like he was hardly using any pressure.

the lamination looked perfect and solid.

the light/soft pressure applied to the lamination looked odd to me so I asked.?

"I always press hard in a fury to get it to look this way, what’s up, why are you so light to the touch? "

(minutes later)

Dave C. started the lam on the other side soaked the cloth like before than looked at me and said “listen” as he squeegeed out the resin pressing as hard as I would, you could hear this snap/crackle /pop as he pressed hard along the resin soaked cloth. “that” he said “are air bubbles getting trapped/created”,he went on “one of the causes of pin holes in your glass job”

I now go slow (UV RESIN) and use a light touch and I have no more of those pinholes like in the photo. Maybe this will help.

Good luck & good surfing


Howzit CFPerry, The trick is to first force the resin through the glass in to the foam and then use the light touch when removing any excess resin from the board. It's good that he showed you how to listen for the crackle of the air bubbles. Squeegee technique is the important part of laminating and you are now closer to being a better glasser. I've always said it's important to spend time with a pro glasser and this is a perfect example why. Aloha,Kokua

Very good thread.

Kokua, I wish I was in the Islands and could come over and stand in the corner a few afternoons and watch you work. Instead I’ll just pick up all your good advice here.


Aloha… Decided to go on with the board as is …The pinholes are only on the deck . I glassed the deck with 1 layer of 4oz E then a week later added a layer of 6oz S glass… So I feel like the deck is sealed . I think the pinhole problem was in the hotcoat as a temp. problem or from whipping air in it when I mixed it up.

Just for Insurance I will coat the deck with Future Acrylic several coats and with the wax too it should be fine??? Thanks for listening.. Don J.


Try supercrylic from smart and final if you can get it,instead of Future.If not use the future in very thin coats,and let each coat dry completely.Herb

Thanks Herb, I am in Fla.We don’t have Smart and final . I have used future before & I know to let it dry good between coats . Wonder if I could thin it down somehow Mahalo to all… Don J.

If you thin it, use alcohol,but just alittle,cuz it will destroy the bond in the acrylic if you put too much in…Herb

OK Herb , I think I’ll just use it as it is and try to put it on thin . But I will look for the Acrylic you suggested… Thanks again Don J.

Grout sealers or other floor sealers like Behr industrial floor sealer are great choices as well.

…I use a old piece of tee-shirt to apply it.

…Dampen the cloth first and squirt a small amt. of Future on it(THE CLOTH). Apply it in a lengthwise pattern ,like putting on a hotcoat.Don’t stop inbetween the swipe,or go back midway and scrub…scrunge btwn coats after it’s dried completely…if you do this enough ,you’ll get my message more clearly.Herb

howdy kokua,

Yes, watching a pro work is like finding a $100 bill in the wash!

good surfing, cperry