I am a beginner, I built a 9’ Grain surfboard. I used your Super Sap Epoxy Resin and Super Sap SRF Hardener for the Laminate and Hot coat. Used Resin Research with Formula F for gloss coat. I sanded the entire surface to remove the imperfections, by hand, I am at 320 grit, and overall it looks pretty good… Of course I sanded through into the fiberglass weave in some areas, especially on the rails. Still if I wet the sand throughs with de-natured alcohol the fiberglass is barely noticeable. However I feel like I need to be sure that the exposed weave areas will not leak.
My question is,
Is there a sealer I can apply to the exposed weave to insure the integrity of the gloss coat through the continued finer grit sanding and polishing.
change course and use a polyurethane, if so, do you have a recommendation.
Re-apply your finish coat to the areas where the weave is showing. Wet&dry with 600 and 1000. Add Additive F to the R-R. Lightly sand this time. I recommend you use water and sand lightly by hand. 1/2 sheet folded in 3rds. You oversanded the first time, don’t oversand a second time. Be sure everything is blended and no scratches. Hit the entire board with polish and a wool bonnet.
I can’t see photos. Is it a glossy or a mat finish?
For mat finish, spray a good quality clear acrylic mat varnish, 2 or 3 layers, clean with scotch brit pad and go. On rails it will “satin polish by itself” with use.
You can also go with acrylic “secret sauce” (ie stone and concret acrylic sealer) spread with a sponge then scotch brit cleaning. Light burn though, when you sanding touch top of fiber on place where there are couple layers of fiber well laminate ( enough resin, no pin holes) may not leek so no worry just cosmetic.
I’m not sure the styren wipe work on epoxy…
From what i see on photo you seriously hit glass on rails and still at coarse grit sanding stage. Best probably to do a new full resin coat and to sand it starting with finer grit.
If I was working on it I’d re-coat with epoxy then final sand and polish(if you want it glossy). I’ve read that poly doesn’t always like to bond well to epoxy. You’ll remove some of this coat in your final processing so that might help with the final weight. Good luck with it! It’s a nice looking board!
Voc less epoxy can be exasperating to use for finish coat, at least more work than hope.
If epoxy is well cured, well prep (sand key and clean) poly hold on it enough forca finish coat. But as most surfboards poly are more brittle (a little stiffer and twice less elongation to break, that’s way epoxy is mechanicaly a better resin) when skin bend poly finish cracks first. If skin is buid “stiff” need a big impact so not a problem.
Polyurethane Foam, Epoxy Resin and Warp or one of the new “S” Hybrids like they sell at Graphite Master. If Swaylocks readers haven’t visited their website, It’s worth a look. graphitemaster.com
Here is my Re-Gloss Coat process for 9’ wooden surfboard glassed with low voc epoxy resin.
Lightly hand scuff coat sanded surface with 120 grit.
Re-tape fin box
Fill leash plug and vent plug with spackle and lightly sand.
Using a clean dry chip brush, remove any sanding dust.
Blow off surface with dry compressed air
Wipe down surface with de-natured alcohol
Start with bottom side up, and tape off rails at just below mid point apex.
Mix total of 12oz of epoxy resin.
Slightly heat the batch with med setting hair dryer at 90 degrees to side of cup while stirring to thin and release bubbles in mix.
Carefully and as smoothly as possible, pour about 1/3 of resin followed with firm wet brush pressure with from nose to tail, stringer to rail, being sure to overlap each stroke then do other side. Then cross stroke with a lighter pressure brush entire surface at 45 degreesfrom nose to tail then reverse from other side from tail to nose.
Brush out rails and make sure rail to tape edge is saturated.
Carefully inspect coating, checking for brush hairs and remove using two razor blades.
Brush surface from stringer to raise from nose to tail with very light pressure almost vertical brush strokes
Wait a few minutes and watch as epoxy levels out
Using a hair dryer at med temp, quickly moving dryer back and forth to try to remove any tiny bubbles that appear. Don’t stress if bubbles don’t respond because they can be easily be sanded out, during the sand to polish process.
Remove tape when the drips on the tape are slightly tacky to dry but not wet to touch.
Ok this is exactly the process you can find in many forums, that’s sound good and i bet you’ll have problems and you will know why you also often read that epoxy finish coat is a nightmare!
Pro tech: wear gloves, sand with new paper, brush of sanding powder, no blow, no wipe only brush or vaccum cleaner. Clean with epoxy: prep a little epoxy squegge it on then off the board, wait a little then brush on your main coat. Make enough resin to be able to cover the whole board with a thick coat with minimal new brush cross. Max three cross nose to tail, rail to rail, nose to tail again only if needed. Let resin self leveling. No alcool, no dryer, no blower, no… only what’s needed.
I have experienced enough nightmares trying to finish this board. I’ll consider your modified finish techniques which sound logical and in process like a hot coat routine. Even though I put a new water and oil separator on my compressed air nozzle so as to not introduce contamination but a vacuum is probably batter.
I don’t want to beat this to death but, should I reconsider using a polyurethane finish, seems simpler, but I have read about adhesion and cracking problems, or marine varnish, not wild about multiple coats and amber coloring. Factor in this is a wooden surfboard that has different expansion and contraction characteristics and is stronger than a foam blank. What do you think epoxy, polyurethane or marine varnish.
The simple and easier to do is to brush a polyester gloss coat. Easy to lay and sand, can go up to glossy finish with polish. As a finish coat over a strong wood and fiber skin no problems of cracks. Best finish would probably spray 2k polyuretane varnish, need place to d it, some have top results with 2k pu cans.
