Hi all,
I'm after some advice on my first attempt at repairing a ding on my beloved SMIK board. A fairly minor puncture ding was transformed into a fiasco by using polyester resin instead of epoxy (yeah I know, rookie mistake). Upon advice from Scotty and Colas (thanks again gents), I filled the cavity with polyurethane expanding foam, which was a success. I then sanded the foam and about 1 cm on every side of the wound (see picture).
My question are:

1 - do I first fill the hole/ exposed foam area with QCell and epoxy resin, sand, then apply 2-3 layers of fibreglass? Or do I go straight with fibreglass layers with resin/QCell mix?

2- for the sanding coat, what proportion of Qcell to resin is required to make a putty?

3- I plan to mix black pigment in the sanding coat to blend in with the black paint. Any advice on quantity/method of colour matching?

4- is the 'hot coat' only composed of resin or is there another additive required to seamlessly "seal" the layers?

5- further sanding required on that final hot coat?

I know that's a lot of questions and I would greatly appreciate your advice.

Cheers,
K

I'd just put a sticker over it and get back in the surf

Yeah or a bit of rail tape. Thought about it, however that's literally only a band-aid solution

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KimboNogo said..
1 - do I first fill the hole/ exposed foam area with QCell and epoxy resin, sand, then apply 2-3 layers of fibreglass? Or do I go straight with fibreglass layers with resin/QCell mix?
2- for the sanding coat, what proportion of Qcell to resin is required to make a putty?
3- I plan to mix black pigment in the sanding coat to blend in with the black paint. Any advice on quantity/method of colour matching?
4- is the 'hot coat' only composed of resin or is there another additive required to seamlessly "seal" the layers?
5- further sanding required on that final hot coat?

1 - no need to fill, you can apply directly on it
2 - about 1:1 in weight, and around 1:7 in volume (7 volumes of Q-Cell for one of resin)
3 - just a drop. a tiny amount is sufficient, I just dip a woodstick in the pigment and put it one drop at the time and stir, you quickly see when you have put enough. Using pigments to approximately match the board color is a good solution, it requires much less painting for a perfect color match.
4 - real hot coats are just pure resin. Pro shapers can add additives, but it should only be the ones specifically recommended by the resin maker. Be careful not to incorporate air bubbles when stirring, stir slowly without vertical motions.
5 - sanding and polishing. A cheat I use is sanding, then spraying 3 layers of varnish on it, mat or glossy.

Never use tape, it is too risky on EPS. If you are in a hurry, solarez + a 365nm UV lamp (cheap on amazon) and you are back on the water in minutes.

Colas, thank you for taking the time to provide this valuable information. Much appreciated

+1 for Colas advice.
Forget hotcoat its a surfboard thing and that repair will need to be painted and blended out - hard.
If you do want matte clear over, British Paints satin clear in spraycan at Bunnings will be pretty close

Thanks Mark. Any tips for blending out matte spray paint on the black paint /brushed carbon look already there? Wet sanding /polishing with ultra fine grit paper?

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KimboNogo said..
Thanks Mark. Any tips for blending out matte spray paint on the black paint /brushed carbon look already there? Wet sanding /polishing with ultra fine grit paper?

I do not use tape for delimiting the repair, as it will make the transition between the repair and the rest of the board visible. Even if you use the same color, the old paint may have faded a bit with the sun and is not exactly the same color anymore.

I only protect with tape things that are a different color (pinlines,graphics, pad, other colors), but mask the rest of the board with a piece of carboard that I hover 1" - 2" above the rest of the board to semi-protect it from the spray. It thus makes a nice gradient of color between the repair and the rest of the board, making the transition much less visible.

For the brushed carbon look, you have to spray paint, let dry, and lightly sand. It is not easy to get the same look as the rest of the board, you need to practice.

^^^ +1 again.

Going to be a hard colour as it looks charcoal not black. plus its matte.
Really going to need a gooooddd paint guy to match it for you as fading out with sanding never works man.
Then you have paint match - but that needs a spray gun.

A disposable sprayer like a Preval is only $20 but by the time u have that and the paint it may be better to just pay someone to do the topcoat once you have it all primed and schmick

Or, get as close as possible to that blue and do a semicircle up from the bottom / rail tuck to cover the repair, and will look like its supposed to be there. Often the best option is not to try and match - deceive instead.