I have done some wood surfboards, and I find it hard to laminate and see how your work is going when laminating over a white (no contrast!) blank.
Im pretty sure those bubbles werent there before hot coating though.
I was searching on the archives trying to find what the problem could have been, and read something about applying the hot coat over a lamination that`s been done many days before ( also my case ), and getting lots of micro bubbles.
Someone suggested that you should apply a cheater coat before the hot coat in these situations.
You could wait a month with Poly and it wouldn’t matter. What you worry about when you don’t hot coat in a timely matter is whether or not the hotcoat resin will stick. With time a laminate loses it tackiness. Has nothing to do with bubbles. If you have bubbles in your hotcoat, something’s going on with your hotcoat. Even if a lamination sits months or years; There are ways to re-tacky the resin of the lam so that it will take a hotcoat. Funny; The longer you let a lam set the less possibility of any off gassing etc. So almost zero possibility of a lam being the source of bubbles in a hotcoat…
I hotcoat in far less than ideal conditions: basically outdoors in a covered area. When I get bad results it’s usually for one of a number of reasons:
not careful enough to avoid contaminating surface via touching finished board (less an issue with lams than hotcoating). Solution: don’t be so careless, no amount of care is excessive
lamming over paint (again, less an issue in lamming than hotcoats – most paints will cause fisheyes when directly hotcoating onto them without putting down a cheater coat first). Paint pigment activating (mixing with resin) is a much bigger problem when lamming, and usually the solution to that is either do a squeegee coat before lamming, or be quick and mindful of how you spread and move the resin when squeegeeing.
most important one: lamming in wrong temperatures or when temps are rising, or with resin that isn’t at the right temp and consistency. Fixes: lam only when temps are steady or decreasing, if you aren’t sure whether your resin is too viscous or not, heat both resin and hardener as part of prep (and be aware you will get a faster kick – this can be addressed by lamming with slow, but if you lam with slow and Aerolite S-glass 6 oz you now have a different consideration with laps wanting to come up.
I had a big problem with bubbles onto an afterthought lam of 4 oz S-glass Aerialite (I can’t remember how to spell it right now, don’t have time to look). I was making a board for a friend who is a beginner, and I know the board will get rough treatment, and it’s not important that the board be light, so after completely lamming with 6-oz S-glass bottom, and 6x4 deck (with S for 6oz), I decided to tape off and add a full length 4 oz to the bottom. The board had been sitting a long time. It was cold, like 55 degrees out. I didn’t check my resin before mixing. The resin looked OK going into the cup, but when I started mixing the hardener it was obvious I had made a mistake. It was not a board-for-hire, and the full lam was solid, so I thought, F*** it, and went ahead. It went on like taffy, but it looked fine when I was done. After it was cut and hard, though, there was a catastrophic bubble issue all around the lap edges from the deck lam’s overlap. IMO any of these could have saved me: (1) sanding better - more carefully and coarser grit - especially the flat 6 lam’s surface, with special attention around the lap line from the deck, (2) being patient and waiting for a warmer day, (3) heating the resin. Probably #1 would have been only somewhat sufficient. Probably #3 alone could have prevented the problem.
sorry it took so much to write back. It is high season here and it gets hard to find some free time.
That`s why so much time went by in between each of the steps.
I think my main problem is been due to gassing. I did the deck in a hurry in extremely hot conditions. I could not stay monitoring and hunting for bubbles for more than five minutes.
May be those bubbles were already there and the hot coat just showed them off beautifully.
good new is I tried the board yesterday and it Flies!
It never was clearly stated, but obviously you are using Epoxy. Why people have so much trouble with Epoxy, I don’t know. Technically an Epoxy “filler coat” is not a “hot coat”. From what I have seen and heard on this site; bubbles could come from anywhere with Epoxy.
I tend to get bubbles in my fill coats when mixing the two part. I found using a wider mixing stick reduced this problem and don’t whip it up. Slow steady mixing. I like your fish, too! Mike
Cool tip! I can think of a bunch of possible uses for that (glass coat? burn through patch? etc.).
Have you experimented with it for other uses like “acrylic coat” that would normally be done with aerosol or gun?
I’ve sprayed a handful of finished boards with rattle can acrylics (3 or 4 different types, so maybe this is actually more like a dozen or two). Upsides: easier to sand to glossy polish than epoxy resin. Downsides: seems to stick to water, boards literally feel sticky in the water (and I swear they seem to go slower), and the paint eventually scratches and/or wears off (not sure if it peels off via a spray-on paint application, but it definitely abrades off).
