After consulting with Brian of GreenLight Surf Supply I got the low down on how to fix dings. Granted this was a bit more then a typical ding repair.
You'll need a few supplies to get the job done, you can find most of these things online by searching for epoxy ding repair kit. Luckily I had left over supplies from my last board build.
The first thing you need to do is clear and cut away delaminated areas. Normally you can leave this on and just apply a quick coat of epoxy to "re-glue" it back down. But my particular case some of the foam beneath it separated and I needed a clean area to fix this. After it's been cleaned up, tape up the fin plugs and sand everything down about 2 inches past the inbox and rail using 80 grit sand paper. You basically want to scratch up the surface so you can get a good bond when epoxying later on. you might notice some yellow on the foam. I didn't have any q-cell resin so I just glued the large piece of foam that got popped off. Worked a charm.
At this point you want to cut 2 patches of 4oz fiberglass cloth the first patch being small and going over the edge of the ding. The 2nd patch should be larger covering the smaller patch.
At this point as you can see I painted the foam to match up the color of the surfboard. I didn't want to completely hide the damage, so I only did one coat of color to show through the carnage. Make sure to tape off the surrounding area, you don't want to make more work for yourself later on with the sanding.
Lay down the cloth and then mix up the epoxy. When it's ready, pour the epoxy over the cloth. You know you did it correctly because the cloth will become transparent. Make sure to squeegee and roll over the rail and clean up any drippings.
I wasn't about to go and toss the old fin plug, especially since it was undamaged. Recycling it was an easy process. I used a sander and removed the excess resin. I also went a step further and cut in some notches to make sure it would hold in securely.
I went and made a simple epoxy dam in case I got a bit of an over flow. Before inserting the loose fin plug, make sure to mix up some epoxy and careful pour some 1/3rd of the height into the hole. Then attach the loose fin plug to a fin and then attach that to the board. Now the fin will be in it's proper place. Carefully pour a bit more epoxy till it tops off. Let it dry for a few hours or over night.
At this point you should have a pretty rough looking repair. Get that 80 grit sandpaper we used to rough things up and sand down the epoxied area. Be careful not too sand too deeply as you might get what is called "burn in" which just means you sanded down to the cloth. Not a big deal if you do, since the hot coat should take care of such things.
We're almost at the final step. Mix up a tiny amount of epoxy and have a disposable 4” chip brush or something smaller. And paint on the epoxy over the rough edges, you should see everything smooth out and fill in any gaps or holes. Let the hot coat dry. And finally get a 100grit sandpaper and remove any of the gloss from the application of the hot coat. next get 200 grit sand paper and smooth that out. Lastly use 300 grit sandpaper and smooth out the area again. At this point you can go and use higher grit sandpaper to smooth things out even more.
Throw on the fins and enjoy your board all over again.