did things a bit in a hurry because of very high room temperatures.
just finished hot coating top and bottom, not sanded yet.
anyone knows how to fix this issue?
the easy way or the pro way?
and why did this happened?
cheers and good waves
Air between layers not enough lamination pressure, resin kick too fast ? Cut out and patch with glass.
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Follow lemat’s advice. Next time; more squeegee work and more resin on the rails when you tuck. I sometimes use a 3” cotton roller to wet out my rails. Tuck them from mid board towards the nose and tail. Use a plastic squeegee to tuck them. That is dry cloth and air. Ask a painter why he “double rolls” a wall with his roller? The purpose is to make sure there are no missed or dry spots. Maybe consider using a few less CC’s of MEK to give you a little more time to work the resin/cloth. If Epoxy maybe go to Slow hardener. Another solution is a “cheater coat”.
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thank you very much!
ok, what is the mix to turn normal laminating resin into cheater coat resin?
do i have to sand the hot coat first?
if so up to what grit of sandpaper?
cheers and good waves.
The problem is your lamination, not the hotcoat.
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A “cheater coat” is applied as soon as you have finished laminating. While your laminate is still wet. You pour half or less of what you used to lam. Catalyze it and spread it over the whole lam and squeegee off the excess. A lot like the second coat a painter applies to a wall. Has to be done while your resin is still wet(not set).
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Exactly, for poly or epoxy cheater coat is lam resin. Left a resin rich fully saturate fiber llook but with fiber tight on foam, if you do well first coat. When i learned to cheater coat i already move to epoxy lam, allowed me to made first quality lam.
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Ok, so do i apply the cheater coat with squegee or brush?
cheers and good waves.
With squegge.
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You’re basically re-wetting the whole lam. Because it is already wet you only need about half as much resin. It’s an insurance policy. It insures that you get those dry spots that your eyes missed the first time through. Just work fast or use less MEK to make sure you have plenty of time. If you are using Poly, you could go to UV Poly. Gives you plenty of time.
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thanks lemat and oss1.
will do a test, a bit afraid of the extra weigh added by the cheater coat.
cheers and good waves.
Excess resin is squeegeed off. Think about it; You are getting the exact amount of resin you would get if you could do a proper lamination on the first try. This is not a filler coat.
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Yes in fact this two stage lam tech allow a better resin/fiber ratio if you cheater at right time (easier with epoxy large setting window) : when first batch start to set so is thicker than your fresh cheater batch. New resin go where it’s needed and lam stay flat. Sanded coat then flow better, finish is easier ended lighter.
Surfboards skins need to be fatigue strong against composed flex stress, resist impact stress and puncture, need to stay glueded on foam and waterproof. For that ideal resin/fiber ratio is not the mystic 50/50 of composit world. Need far more resin. Need enough resin between to glue fiber to foam, just what is needed to glue fiber eachothers (around 60% fiber 40% resin by volume) then a thick coat over for final shaping, waterproofing and protect fiber.
For usual stretch test, 60 fiber 40 resin by volume with most fiber in axis give best strengh by weight. This is standard usual mechanical test for characterisation of isotropic materials (steel, alu, etc). Not right for composits surfboard skin.
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So what would be a good ratio of fiber resin for a surfboard?
also thanks everybody for the help.
For sealing and gluing on foam, around 150g/m2, for lam fiberglass more or less same weight as fiber, half weight for cheater coat. For fill coat around 200 to 250 g/m2 most will be sand.
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thanks to everibody that helped, building this board was a mess from start to finish.
funy thing with the sanding things are starting to look better.
cheers and good waves.
It’s like someone else said; a good board builder is good at hiding his mistakes. I figured that with some extra sanding and maybe a piece or two of cloth would clean it up. Try the cheater coat next time. A lot of pros use that method. I do it because my eyes aren’t as good as they once were. Can’t always see my little dry spots.
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i will try the cheater coat.
now lets imagine i finish doing my lamination do i do the cheater coat more or less right after the lamination ot do i let the laminatiom harden a bit, like 30 minutes or so?
Don’t wait . Do it immediately.
rigth on, thank you very much.
So lets see if i got this correct this time and please let me know if i am wrong at what point.
1- normal lamination (regular lam resin)
2- cheater coat (regular lam resin)
3- hot-coat (Lam resin + 3% wax )
4- sand to 320 grit
5-gloss coat (lam resin + 5% styren + 2% wax)
6- wetsand up from 400 grit
7- Polish
cheers and good waves.