The dings I’ve had professionally repaired come back to me glossy and almost invisible, while the ones I attempt myself look like shite. I’m talking here about ones that have cloth on them. To make my questions simple, let’s assume this is a ding that’s fairly flat but needs some cloth. I’ve roughed up the surrounding area with 80 grit, laid down tape around the ding, laid down the cloth, put on the epoxy (I am using epoxy), covered the patch with plastic sheeting, squeegeed the thing down flat, let it dry, and cut around the patch. Now I’m left with a flat patch that is nonetheless higher than the surrounding area and that also has that sharp edge. So, I start working on hand sanding the edge with 100 grit … but can never seem to flatten it out so that it disappears. I dunno why not; it just seems to continue to have at least a little edge no matter what, even if I start going to finer grits. Could it be I’m giving up too soon?
And then there’s this: with the cloth and the epoxy on top of it, how do you sand the surface down so it’s level with everything else without sanding through the epoxy into the cloth? I mean, when I’m roughing up for the repair with 80 grit, should I also be sanding out a depression for the cloth/epoxy to fit into? I just don’t get it. Can I get a little help on this vexing matter?
And then what happens when you glide on a gloss coat? Doesn’t that raise the repair once again?
Okay, first off, you may be sanding too coarse. Try feathering the edges first with 100 grit, then going to 220.
Don’t use a sanding block, whatever you do. A fingertip and fine paper, right on the edge, that’ll do the trick. Round the corners, don’t worry if you sand away some edge and make it irregular shaped. That will be harder for the eye to pick up anyhow.
Now, rather than squeegeeing the cloth under plastic, which I haven’t tried, I like to put resin on with a brush, using as little as I can get away with to make the cloth transparent and leave a good weave texture. And much less that needs sanding away, y’see. The plastic should leave a smooth surface, which is nice, but if you are gonna hotcoat/gloss it anyways, why bother?
When you put that gloss coat on there, it is higher than the surrounding area, but not all that much. Not enough to matter,anyhow. Likewise with the repair itself. Sanding out a depression for the repair is fraught with peril - chances are you will sand away enough cloth to negate the repair itself, y’know?
Just go easy with the brush, so you can put just a thin coat on that edge and then thicker over the cloth weave. Mask around the area you’ll be glossing, for a transition. I like to pull the tape when the resin is starting to gel, if ya get lucky the edge ‘collapses’ a bit and saves you work. Wet sand to 300 grit and polish and that should do ya.
Howzit doc, You got it. The thing is to be able to know just how deep to sand the ding before adding glass and resin so the repair comes out even with the rest of the board. It's an eyeball thing that comes from doing a lot of ding repair. Aloha,Kokua
just a couple of things that I’m not sure were inculded in that fine write up: if your using 2 layers of cloth, make the second layer slightly larger than the first. Also once if feathererd the edges of the patch and am moving on to the fill coat i extend this again a little larger than the patch, all helps for a gradual contour.
Doc mensioned pulling the tap early to get the edge to collapse a bit and that does really help.
IF you can find a copy, there’s a booklet called the “ding repair scriptures” my copy is pretty old. try Bank Wright’s web page.
you should be cutting down into the area around theding and then filling it up with your cloth and resin , then sanding with finer and finer papers—the last being 400 or so wet and dry and add a drop of liquid soap to the water you rinse the paper in–this will keep the paper from clogging and make the final result pretty nice—finish with some “mother’s car polish”<–thats a brand name–really good stuff
Howzit woody, I actually do it the opposte way and cut the first layer of glass the biggest and then the next layer/layers smaller. This way if you sand to much you don't sand into the outer edge of the biggest layer which weakens the repair. Plus I rarely use any tape off so the glass lays down nice and flat. Aloha,Kokua
Go to “Contents” then to the article and flick through the pages. It seems to come down in favour of biggest patch first, which is the opposite to the way we in the UK are taught.