Ding repair FAQ
Fibreglass for Surfboards ——————————
Dings —– For big holes – clean out the hole, cut a chunk of foam to fit and stick it in with resin. Shape (180 grit) and re-glass. For small holes – pre-mix glass beads with resin. Add catalyst as normal : ie 7-8 drops MEK per 20ml of resin (more if cold, less if hot weather).
Reglassing – (torn or missing glass). Clean all torn bits. Fill any hole or depression to taste. Feather the edges of the glass (sand @ <30 degree angle) with 80 to 180 grit.
Wipe with acetone soaked rag. Cut glass cloth to slightly over cover hole+ feathered bits. Mix resin. (if anything go under on the MEK). Use a bit of sponge/squegee to apply resin to totally wet the glass.
Then use the sponge to remove all excess. Do this by dabbing/wiping with the sponge, periodically squeezing out the sponge.
The finished surface will have the texture of the cloth. Once this has set, sand (w’ #180) any rough bits or high spots.
This also keys the resin for the hot coat. Mix another batch of resin, this time hot (extra MEK – 1 extra drop per 20ml). This will gell really quickly (5-10 minutes).
Brush on just enough to provide a smooth finish.
When set, sand smooth with progressively finer paper (180, 280, 400, 600 then cutting compound) until either bored or satisfied. [Mals tend to be finished with an additional hot gell coat, and highly polished- competition boards are often not even sanded at all.] Resin, MEK and microballons can be bought from most shapers.
Offcuts of foam and cloth can usually be scrounged from the same sources. The process I’ve described is time consuming and most shops don’t do that when they “fix” a ding.
They mix up a hot batch of resin with lots of microballons, fill the hole & sand.
It’s quick (only one setting time vs 3 or 4).
It’s also weak. Some at least mix some chopped mat in to give it some structural strengh, but you’ve still got a future source of leaks.
Ding Repair Suggestions (Eric N. Valor) —————————————
First off, fill the holes with foam. Most surf shops that do ding repair may have some around that they’ll flow you. Either that or find a shaper in the area. But do NOT fill in a hole with just resin; it makes for bad weight and an ugly repair.
Cut out the hole until it is nice and even, then cut a piece of foam to shape and insert. Make sure it matches up evenly or you’ll get ugly lines. btw: that powder is most probably microballoons; small glass bubbles with air.
They space out the resin and make it a bit lighter.
Ok, next: Use 10-12 drops of catalyst per ounce of resin. I don’t know how big your dings are, so I don’t know how much resin to use. Just eye it.
Stir the catalyst in for about 60 seconds to get a good mix. Then coat the bottom of the “filler foam” with a bit of resin and insert into the hole.
Then cover with a sheet of fiberglass (cut to shape of the hole) and pour a little bit of resin on top and smooth it out over the hole and the existing glass (you’ll sand off the excess later).
Put a piece of Saran Wrap over the top and let set overnight. You can use 80 grit sandpaper to start the process, then once you start to get down to the existing glassjob, switch to 100 or 120.
To finish off, use 400 wet/dry (and use a bit of water). That should do you. Fins are a bitch to set properly, as placement of the fins absolutely determines how the board will respond.
Make sure you get right and left fins for the twins (yes, there are sides) and a normal single for the rear (this is a tri-fin, right?). Angle them out a few degrees from straight up-and-down, and toe the front edges of them in just a bit. This is the hardest part, as they have to be braced while the resin dries.. it’s a bitch and I’ve only done it (badly) once.