I learned basically everything I know about glassing with epoxy here on Swaylocks.
Mainly from Stingray but also picking up tips and tricks from countless other Swaylocks posters.
I don’t usually do a 2nd hotcoat but, on my last board, I made some mistakes and was forced to do one and I had a bunch of fisheyes.
To be clear, I put the 2nd hotcoat on AFTER sanding the first one. And, honestly, if I hadn’t screwed up with the finboxes, I would have been fine with my first hotcoat.
Any tips, tricks to avoid/minimize the fisheyes?
Was it dust on my previous hotcoat that caused this?
I am OCD about ONLY touching a board with fresh rubber gloves on so, I don’t think it was oils or contaminates from my skin.
Lamination coat and get filler coat on just past sticky(if possible) top and bottom.
Sand board(I don’t go past 180 grit) to shape and expose all your pre-glass install fin boxes,vents, leash plugs, mast boxes, etc. Your board should be water tight and able to surf at this point.
Final coat I wash the board with a body scrub thingy with soap and water and dry with clean rag. With my clean hand I can drag across board and feel if it is clean of micro debri or not. Tape off rails and boxes,plugs etc. Use 4" double thick chip brush after prepping brush for use. Lay resin and I always use the west coast fast cure. Keep an eye on things to ensure full coverage and be prepared to mix up a few cc’s of resin and put in any fish eyes that may form.(Won’t happen with green room). With the west coast fast cure you know what you have in 15 to 20 minutes regarding fish eyes.(my experience none) From here you sand and polish or whatever method you finish your boards.
Lastly, I know what “hot coat” means when using polyester resin. What exactly do you mean by it when using epoxy resin? With epoxy I do a 1.lamination coat 2. filler coat 3. final coat.
I use Resin Research and pretty much haven’t seen a fish eye in years. But there are other good products as BB30 says. Here is a little snip I’ve saved and pasted here many times:
Epoxy Hot Coat Gloss
Per G Loehr: You’re working too hard to try to make everything perfect and in the mean time you’re adding a bunch of potential problems. After the laminate you sand lightly mostly getting the laps flat and all the high spots down. Wipe the excess sanding dust off with a white Tshirt or a paper towel. Tape off around the perimeter and sqeegee your cheater on if needed. Let that tack up and then brush on your hot coat. I only use 1 cc Add F per ounce of hardener. That’s adequate and using more may give you problems. I only use more if it’s extremely hot (which it never is in SD) or on a gloss. Rolling on the hot coat may have made it too thin which could have made it bead. Use a brush, a new one, a 3" chip brush. If you push the bristles into the sticky side of a piece of tape before you hot coat you can remove loose hairs. If you don’t the brush may shed a bit but unless the board is colored you probably wouldn’t see them anyway. Brush on a normal hot coat. It should flow perfectly. This is the way I do it … simple. I never get fish eyes.
Picture of filler coat from last Sunday by a person I am helping make his board. He has never done a filler coat"hot coat" with epoxy but this was his first. Green room epoxy lamination just past tacky. On sunday that was about 20 minutes after finishing. Prep was nothing except getting excess hairs out of 3" chip brush and taping off brush to keep bristle hairs from coming off. No tape off of board because you want to fill the lap also. Because it is a wood laminate sanding off excess filler coat on rails is not a problem. Green room gels so fast that babysitting the rails with brush wipes is short lived. Green room epoxy with west coat fast hardener was used. it was flowing like water, gelled up quick, I just watched and pointed out a few bristles that needed picking up. Some high areas because as a newb it took twice as long to do it as I could and it was a very hot day. I would give him a 5/10 for his first. If I could get it that good with any other epoxy product I would have been stoked. With the Green room I am acheiving gloss like filler coats. When I vac bag with green room using CF cloth I only use the inital vac lam and final coat. Curious what brand of epoxy are you using??
Pic below- Last Sunday FIRST hand lam and filler coat for human under my supervision. Believe me when I say it was the resin and not the teacher.
I’ve been using FGH epoxy and the only times I got fisheyes was when I tinted the resin “hotcoat” because my “tinted” lam didn’t turn out like I planned (found out the hard way that Innegra doesn’t take pigment very well. My “Fire Engine Red” lammed into “Fire Engine Pink” on the Innegra side and red on the other side).Other than that, I’ve been very happy with the FGH epoxy (especially since I took Wade’s advice & started to mix by weight).
One thing I missed in your post. How did you remove the sanding dust from first hotcoat? I’ve also made the mistake wiping board down with acetone (til I read here that it could cause fisheyes). Now it’s just, sand; blow off with air compressor nozzle & hot coat.
I blew the dust off from the first hotcoat with a leafblower then wiped with paper towels. I used one towel the length of the board, threw that one away then used a fresh one for the next wipe, etc.
All shaping / glassing / sanding / fin box installs happen inside my garage workshop…dust everywhere…a clean shop helps with gloss work…if you sweep and shop vac to clean up the area you also throw up all kinds of micro dust into the air…time will tell…wait for all the dust to settle. Do what BB30 says…After I blow off the board I want a shop with no air movement…oh boy…did you really use a leaf blower…we need to get you set up with an oil less air compressor and a good filter…Ray
I think it’s all about the Additive F or “Qwiksand” added to the epoxy. Put enough in it as prescribed by Greg Loehr, and brush it out. If you get any separation, brush it out again. If there’s any spots that keep wanting to separate, add a drop of resin from the corner of your brush and let it settle out.
Best trick I’ve learned for fisheye-free hotcoats with Epoxy is to lay it on a bit thick with a minimal amount of brushing (don’t overwork the resin), walk away and let it self level.
There is a minimum thickness the resin needs to hold it’s surface tension, too thin and all those crazy things like fisheyes, pinholes, and separations may occur.
Epoxy(resin)…Hot coat(filler coat)…Gloss(final coat). GL really bastardized the polyester glassing termonology with that post regarding epoxy.
Wouldn’t be nice just to have a resin with no quick crap or additive Xylene needed to get the job done every time? Been using it for about three years now, Very idiot proof. Very simple.
If you want to go thin with époxy you have to lower viscosity, works really well with heat. Adding solvent increase surface tension, better levelling, but if solvent get trap it weaken resin.
dust from prepping the hot coat is only epoxy resin dust, it has NO effect on the filler coat, other than perhaps being too “chunky” and leaving dust motes.
I hit the surfaces with my desk brush just to get rid of the surface dust, but I also hit all the boards surfaces with a light grade sandpaper to add a little “claw” and knock off the tops of the tits where the weave crosses, it lets me go with a thinner filler coat and have it lay flatter. I NEVER wipe the glass job down with any chemical of any kind, I try to avoid handling it with bare hands, move it around with scrap glass or paper towels
