I’m gonna go through this too, with a few suggestions- bear with me. it’s your first, and maybe I can throw in a little info/explanations to help with the redo and future repairs.
Okay, ding. But more of a shatter, gloss coat and hot coat damage. Banged it into something, right? What I call a ‘garage ding’. They happen. Board bags, padded ones, are a beautiful thing. Anyhow
You sanded it. Good job, you stopped at the right time, But 80 grit might be a little coarse, which is why you see a kind of pockmarked surface. Coarser paper tends to take chunks. Me, I would have used at least 120 grit and shot for ‘pretty smooth’. Finer paper takes longer, true, and it gums up faster, but at the same time it’s harder to do actual unintentional damage with it. But that’s fine. Get some finer paper, all the way to wet and dry 300 grit, you’ll want it for this and later stages…
Now, filler. You’re right, you didn’t need any. If I were doing the job, for money, I might have tried just a gloss/hotcoat combination as you suggest.
How come? Look at the cloth. You see the surface texture of it where the clear resin went away, yeah, but it’s still saturated, you don’t see the whole weave of it as white fibers, the resin-cloth bond isn’t compromised. It’s fine, what ya have is more or less like a scratch in the clearcoat over the paint and body work on your car. Cosmetic. Even if there was a little of the fibers showing, I’ve used thinned resin well brushed in to resaturate it. So-
A word about filler powders/thixotropic agents, and pigments and other stuff added to resin. See, they mostly tend to slow down the chemical reaction that happens as the resin hardens. You add pigment/tint to resin, it will go off slower. You get tempted to add more catalyst, don’t do it, be patient. With filler powders, whatever-o-sils, they can really slow down the reactions, by themselves. I tend to mix the stuff in to a peanut butter consistency, then add a very little catalyst and apply it.
A very little? Yeah. See, when resin hardens, that’s what’s called an exothermic reaction. Exo-out, thermic-heat, it gives off heat. All fine, by itself, but the thing about chemical reactions is that when they are warmer they happen faster. With a thin coat of resin like laminating or glossing or hotcoating, you add catalyst and put on a thin layer. The reaction makes heat, but it’s thin, lots of surface area, the heat escapes.
Filler, though, not so much. It’s put on or in in a thick layer, heat doesn’t escape, so the resin mix heats up…and the reaction goes faster. Which heats up even more. So it goes off even faster. See where this is going? We used to take the end of a batch of ding resin in the cup, add a bunch of catalyst, stir, set it down and stand back, it would smoke, wax melting on the paper cup, crackle, crack - life was dull at the surf shop, we made our own fun… I once saw a guy use too much catalyst on the filler mix for a big ding, He slopped it (the filler goo) in, masking tape coffer dam mold for it, and he took off for the day. It got so hot it actually set fire to the foam. Left a black soot layer on the inside of the glass, no foam. That was different.
So, what are you gonna do now? You’re right, sand it down, make the filler go away. Carefully, this is where you use your 80 grit, but in stages, so you don’t overheat it. Don’t use a sanding block, it sands things flat and takes corners off, right down into the cloth and foam.
Get to where there’s just a little filler left, use finer paper, carefully. Hopefully the filler isn’t sticking to the cloth and you can get it all out, if it is sticking you either accept it and sand it all smooth and live with the whitish blotch or else go at it with something fine, hardware stores sell things that look like dentist’s tools that work for that. It’s tedious, but think of it as a reminder of when and where not to use filler. You’ll remember it. I did.
Now, if the filler came away nice and you didnt sand or pick into the cloth, great, Again, use your picks and get any loose gloss out, then give it a thick coat of clear resin, brushing it thinner at the edges. You’re shooting for a smooth layer, if there’s some divots and such, sand lightly and give it a second coat. Then sand, finer and finer, to the finest stuff you have, polish, perfect.
Okay, if the filler didn’t all go away, you sanded it smooth, now use some paint or better yet artist’s paint markers, just on the filler, for color match or just accept it, your call, Now you do need cloth over it, Don’t go with color in the cloth, you get a blotch of that color where it laps past the filler. I would go with a single layer of 4 oz, lay the resin on with a brush, not too thick, bush out the excess so you see weave. Sand lightly, feather the edges, then do the gloss thing I described before.
And there you have it…except for one last thing. I mentioned board bags being your friend for garage dings. Well, you have a dark colored board. They heat up in the sun, which does them no good. The reason Mickey Dora Black Greg Noll Cats are rare is they mostly cooked, on a hot day you could watch the delamination spread under the cloth like this really disgusting living blister out of a '60s science fiction movie. Even clear boards get browned by the sun eventually, and I don’t think it does them any good. My own boards ( which are all clear) live in board bags when not in use… Anyhow
hope that’s of use
doc…
