ok, so no matter how clean i try to get my shop before final coat (admittedly likely still not clean enough) i am getting these little bumps in the hot and gloss coats. without these, i would barely have to sand if at all in some cases.
even though they dont look like airbubbles, and certainly dont leave tiny hollow marks when i sand them out, someone told me thats exactly what they are (air bubbles) and that i should be able to breathe CO2 onto the board ‘dissolving’ them out.
are these airbubbles? if not or if so, what do i do to fix?
Somtimes I get what I call zits in my hotcoat it is usally b/c of temp or you set it off too hot. they are probably the same thing, just little air bubbles.
Had that same problem until I got some cone shaped filters from the automotive paint supply store. Just pour the resin through the filter when you apply it to the board. No more bubbles and trash makes it to the board. The ones I got are from Carquest. 190 micron. Michael
Pin holes/pin air - can look little bummps but have an air bubble underneath that has out gassed from the blank, when you sand these will open up and the sanding dust can get trapped and look white
Zits & tits - look the same but are soild and will not open up, just sand them out, they are caused by dust, from the pot brush or in the room.
Craters - caused by undisolves lumps of wax
Fish eyse - little round concaves, cause by contamination such as a finger print or silicone in the atmosphere.
Drips - self explanitory.
Crackle - on the surface cuase bu useing too much catylist
Orang peel - dimmpled like the skin of an orrange, cause by using too much resin or by air current flowing over the blank.
Slabbing - resin does not flatten as sets as its flowing off the board - cuase by using too much resin and too little catylsit.
Sound like you have zits, unless you have a specific gloss room with good extration you’ll always get a few of these, I get tones but thats why you rub out and polish a gloss.
You get better results by using a spray coat in dusty environs but I would still rather put in the extra work for a true gloss.
Howzit surf3184, My shop had a dirt floor with processed sand on top and some thought a good gloss wouldn't work. The trick is just before you add the catalyst to the gloss is to take a piece of masking tape longer than the width of the board and pull it the length of the board to remove the dust fro the deck and rails. You will see the dust on the adhesive side of the tape so keep doing it till you don't see any more dust on the tape, then apply the gloss ASAP. By doing this I never got any zits or other problems. As for the air bubbles, you may have had air bubble pits after sanding and they probably had some sanding dust in them. If this is the case when you apply the gloss it won't fill the holes as it should. Before glossing use your compressor to blow the dust out of the holes then wash the board with dish soap and rinse it all off.
A good, solid spraydown with the hose to wash off the board before glossing is good practice. Then dry it with a CLEAN, lint free cloth.
The best results I’ve had come when I tape off the rails and get everything set up the night before, then the next day, come in, do a final acetone wipe, brush it out, and leave immediately. Minimal movement in the room means minimal dust kick-up. A clean bucket, a clean brush and a clean board are essential.
I’ve built only a few boards. My work space is my garage. There’s do dust control, no humidity control, and no temperature control. I’ve been using RR epoxy with and without Add F.
I’ve had a terrible problem with zits on my boards. I’ve been sanding down the gloss coat and reapplying a new zit coat only to sand it down again. That’s a waste of time, energy, and resin.
I get zits with Add F. If I don’t use Add F I get creators. There no winning. I tried two fluorosurfactants (super soaps) in place of Add F. Creators formed with those surfactants.
I’ve tried the tape trick. That hasn’t helped. I’ve even took one board in the shower for a thorough spray down. On my last board I used Polyurethane for the gloss coat. I didn’t like the finish but at least there were no Zits.
I don’t think that the zits that I see on my boards are from dust. Maybe I don’t understand the mechanism that forms the zits. If a dust particle is a potential nucleation site then maybe dust could have an impact on the finish. If that were the case then I’d think that the entire sanded epoxy surfboard would be one huge nucleation site. Again I don’t think dust is the problem.
Add F is a surfactant. Surfactants have hydrophilic and hydrophobic components. At high temperature (cloud temperature), possibly in high humidity, or some combination the hydrophobic parts wrap back on themselves. When they wrap back they chain and connect to the next agglomeration of similarly affected molecules. I think those agglomerations are called micelles (zits).
Filtering helps. I’ve been pouring epoxy into vacuum cleaner bags and letting the epoxy seep through the paper bag and drip out on to the board. Filtering removes micelles that form when I mix the epoxy. I still get zits on my boards after filtering. I’m supposing that after filtering that the conditions needed to form micelles still exist and so they from right on the board.
I’m in land locked Ohio. I’ll never have low humidity and 70 degree temperatures to work with; San Diego must be nice. It would be really nice to find a nice gloss coat that isn’t epoxy.