Minor ding repair

[gsseirik]

Hi guys! I thought I was getting better at ding repairs after a lot of work on an epoxy board. I just found a couple of very minor cracks in the glassing on the round part on the rail on my Lost polyester board. I sanded around the crack, and made a border around the sanded area with tape. I only had a small tube of UV-resin (dura) at hand. Everything looked smooth until I was gonna feather out the difference in level made by the new resin and the original top coat. I was very careful and sanded by hand with 80 grit paper. I got a couple of burn-throughs in the original topcoat where I tried to feather out the new resin. Are these surfboards very thin coated on the round part of the rail? Or did I use too coarse sanding-paper? I ended up just applying a new layer with resin over the burn-throughs so that I can surf tomorrow. And now the repaired area has sharp edges from where I pulled the tape, because I won't risk more burn-throughs.

Regards from Eirik

[dtc]

80 grit is coarse - you want to finish off with 180 or even 220. Of course you can still sand down too much, and light boards are glassed lightly - Lost ‘standard’ glassing is 4x4. My custom boards are 6x6, so 50% thicker glazing (but are heavier). So you just have to be careful - and be assured that everyone messes up their first few efforts, but errors are relatively easily fixed

[gsseirik]

Thanks dtc! It's a standard glassing. And the dura resin is probably much harder (and need more sanding force). How do you know when it's time to switch to finer paper? I used a sheet of plastic to make the repair thinner, and less tacky. But there was still a noticeable difference in level. Maby I could just start with 180?

[dtc]

The finer grit is (for your purposes) just to stop you going too far without realising it (rather than the normal purpose of getting a very smooth finish). So you switch over when you are getting close to having sanded the repair resin down to the original surface and take your time.

[gsseirik]

Thank you very much dtc:-) will try to make it more smooth. At least I could use the board today.

[waikikikichan]

80 Grit ! For feathering ? I don't even use 80. Lowest I have is 100. I would've use closer to 240 or even wet sanded 320 if it was such a thin layer that you said you made.

[gsseirik]

The thickness was maby a little bit thicker than the scotch tape that I used around the ding. But I could se the sharp "cliff" or edge with the bare eye. I pulled the plastic sheet hard to even the resin out. Thank you waikikikichan:-)

[Naeco78]

I've read that sometimes people just wipe a Hot Coat of just resin (no fiberglass pieces) to even out that last little bit of surface changes around the repair. It also helps eliminate any leftover sanding marks around the repair

[gsseirik]

Thanks Naeco78! I would have hotcoated it if I had some resin. But I just have a small tube of fiberfilled resin. Shipping costs are so expencive, and the shelf life is short on polyester?