New Board Ding Help Please

I recently got a new longboard and it has a 2" puncture in it. The glass is dented in but still intact. Around the area there are circular surface cracks as well. I need some advice on how to approach this.

Should I leave the area dented in and sand down the existing glass and fill in?

Do I need to lay cloth on the area after filling it with resin?

I am not sure where to start since it is a new glossed finish board. Thanks for any help.


If it came through that way, take it back and have them fix it. For free, plus a nice cash back deal.

If not, okay, sand lightly, just enough to roughen things up and maybe go into the hotcoat some, where those concentric cracks are. Clean well, a wipe or two with acetone to get sanding dust out. Clear resin to fill, in a masking tape frame ( make sure to use surfboard sanding resin) , sand again, glass over with 4 or 6 oz, sand the edges and wash with acetone to get the wax off it ( styrene wax is part of sanding resin, it rises to the surface and acetone or styrene will get that off) and then give it a gloss/hotcoat, brushed on inside another frame of masking tape. Remove the tape as the resin starts to gel, sand the edges with wet/dry sandpaper, start with 150 and work your way to 400 or 600 grit, larger areas sanded with every finer grit, plus plenty water. You can polish at the end if you want, but don’t use any polish meant for automotive use - it contains a red abrasive which can stain resin.

hope that’s of use


Howzit doc, If I may make a suggestion, if the ding is on a flat part of the board i would pull the tape used when glossing as soon as the resin has been applied so it will flatten out smoother than if you wait for it to start gelling. I f ti’s on a rail I pull all the tape except the bottom tpae since the resin will flow over the tape because of the angle.Aloha,kokua

Hi Kokua,

yep, I agree and that’s what I should do myself, that and putting on the gloss a little less heavily

best regards


I get board dings constanly especially in the boards I make, my last board that I got a glass job by stingray for christmas I rode it two times and and an inch of the noses foam came off because it hit a wall when it fell over in my room (I really need racks for it to keep my boards safe !!!) so When my dad and fix boards as long as their water proof its good enough for me b/c I wanna ride my boards ASAP

Thanks! I am on the right coast and my boards are shipped. This one was banged hard. I am skeptical about cutting out the indention or just filling it over with resin, patching it and glossing it. I tried to lift the indention out but its in there good. If it were one of my other boards I wouldnt be so paranoid but its brand new. Is it essential to put cloth over the ding after I fill it with resin? What grit paper so you usually use to start sanding down the gloss coat so that it blends with the board since you will have to sand the edges there too? I am afraid I am going to create a indention around the ding by sanding down the edges.


You can’t be afraid of the ding, or you won’t be able to fix it. It’s an easy repair but it will take care and patience.

First you have to make sure it’s super clean around the ding - clean about 4" past where you think you’ll be sanding. Use denatured or rubbing alcohol.

You have to decide whether or not to remove the compromised fiberglass. If the board has fancy colors or graphics you might want to try and preserve the original glass. If your board is clear or a solid color, use an exacto knife and cut it out. Cut it cleanly all the way around the ding and dig the jammed-in stuff out.

Use 100 grit sandpaper and sand to about 1/2” or so past the newly cut hole in your board. Don’t skimp on this part. This effects how everything sticks together to become beautiful again.

If the hole is deeper than about 3/8”, try to find a small chunk of polyurethane foam to stick in there. If that’s not possible, use cabosil or something similar. You’ll need the cabosil anyway. It’s easy to find almost anywhere that sells fiberglass - surf shops (expensive, but you’re supporting your surf shop), boat supply stores, plastic shops, and some hardware stores.

Mix the cabosil with resin, catalyst, and pigment (if necessary) into a thick paste – first mix the resin and catalyst, then add the cabosil – it will probably take about three times (by volume, not weight) cabosil to resin. You have to work quickly here since you don’t want the resin to kick before you get it in the hole.

Pack your mixture in the hole. Push it in well so there are no voids or bubbles. Leave it proud of the hole about 1/8” or more. When the patch starts to harden, you can go over it lightly with a shureform or rasp to get it close to final shape. Be careful not to overdo it – still leave it slightly proud. After the mix dries, sand it with 100-grit paper and blend with the surrounding area.

Tape off about 1/4" past the patch. Next cut a piece of 6 oz glass so that it overlaps the tape. Use a squeegee to wet the glass with catalyzed or sun-cure resin. Make sure it’s thoroughly wetted out, then squeegee out excess resin. When it is almost cured but still slightly flexible, use your knife or razor blade to trim the glass to the edge of the tape. Then remove the tape – this is way easier before the resin is fully cured.

Sand again, feathering your patch to near perfection using something around 180 or 220. Also, you probably should use some sort of sanding block.

One more coat of resin should do it. Brushed on as smooth as you can – no tape this time.

Wet sand with progressively finer papers – start with the finest grit that noticeably works – end up with 800. If you want it perfect, you can buff it out as a last step.

Wasn’t that easy?

hey doc,

are you using sanding resin to apply the fiberglass?

Thanks scott

Hey, Scott

yes, you can get away with sanding resin for the glassing, you just need to either do your hotcoat/gloss before it sets up much or else sand it lightly or wash it with styrene or acetone to get rid of the wax film on top of the sanding resin. I prefer to do the wash method; you don’t weaken the cloth any and it gets into the little crevices and such in the weave that you get if you squeegee the cloth a little for the best lamination.

meanwhile, back at Toes Over’s board…




Nice, simple repairs get to be major projects when somebody goes cut-happy or router-happy. Leave well enough alone. Put the knife away.

Likewise filling with foam. Look, everybody talks about putting in chunks of foam, a few do it, and I have maybe seen two who did it right…over 30+ years in this business. And lots who did it badly - very badly. What’s REALLY amusing is when somebody tries to bed the foam chunks in a molded cofferdam type deal and pour in resin or sloppy-wet cabosil mix around 'em.




foam floats in resin, you know…




they wind up with this sad, foolish pool of resin with foam chunks floating on top of it, like the marshmallows on top of a Jello fruit salad and about as useful.

Okay? Good. Don’t go nuts on this. This isn’t a major puncture, right, it’s a dent in the bottom with concentric rings of cracking in the hotcoat and gloss, like a bullseye. You don’t need to cut anything, just fill. And sand a little with maybe 80-grit, by hand, with a fingertip maybe, to roughen up the surface so the resin will adhere. Don’t go nuts sanding, just rough it up a bit.

Then, clean it well. I would use clear resin to fill, no cabosil. Why not?

Well, what’s the function of cabosil? It does two things - first is it makes a paste from a liquid so you can wad it in and it won’t sag on a non-horizontal surface. But the problem is that the thicker it is, the more it tends to get bubbles trapped in there, which are a bad thing. Either they crack or you wind up sanding into them and have to do the whole filler thing again. And cabosil mix never levels itself, there are always mounds or lumps that you have to sand. Hassle city. Don’t use it unless you have to.This is a flat surface ding that doesn’t go all the way through, you don’t have to.

The other function of cabosil mix is as a filler to mimic foam, so you don’t get a translucent or near-transparent chunk showing like you would if the ding went well into the foam and you filled with clear resin. Cabosil mix goes off white-ish, and looks like a blotch if you use it on top of cloth.

You don’t need or want to have a blotch, you want something clear. Plain clear resin, maybe even thinned a little with styrene or acetone so it’ll level better and seep into the cracks you’ve described. And pour it a little less than ‘full’, so your cloth has someplace to go.

Get out your 80 grit again, sand lightly to give it some ‘tooth’ so the cloth will stick to the resin fill and to deal with the sanding resin wax .

Then, it’s glassing time. yes, use cloth, or else the filler can crack and fall out and where’s the fun in that? You want some 4 or 6 oz glass cloth, sanding resin and a throwaway chip brush or squeegee. For somebody who doesn’t do a whole lot of glassing, the brush is the way to go. Set the cloth over the filler resin and brush in just enough resin to make the cloth transparent with no bubbles. Your patch shouldn’t extend beyond the edges of the original depression.

Let that harden, sand the edges to feather it smooth with your 80 grit pal. Just the edges, not the whole thing, and lightly. For the rest of that, you do what i described above with the acetone or styrene to get the wax off the very surface of the cloth, so your hotcoat will stick nicely. If you used laminating resin to do the laminating, cool, you can skip that part, otherwise, it’s acetone time.

No sanding block, by the way. Again, I have seen guys get into a lot of trouble with sanding blocks, including one swifto who managed to sand through the original cloth on the rail of a board. You can get it plenty close enough with your fingers and you are a whole lot less likely to screw up something in a moment’s inattention.

yes, I might attack it with an 8" disc sander. That’s me and a lot of time in with one. And a lot of screwups back when. The Hippocratic Oath comes in here: ‘First, do no harm’. Go with the method least likely to make major problems if something goes awry.

Okay, hotcoat time. Mask around the sanded area. Brush on resin with a new throwaway brush, enough to do a little more than fill the weave of the cloth and blend the edges. Pull the tape, as Kokua said, and if you’re lucky you’ll be pretty near good to go.

Otherwise - if it’s not as smooth as you’d like, then as I described before, wet sand lightly with finer and finer paper, up to 400 or so if you are gonna polish it or 600 if you’re not. And then you’re good to go.

Oh, and Chano - I happened to be looking at the latest issue of Fine Woodworking ( check the local library ) and they had some kinda neat racks in one of the articles, described as ‘lumber racks’. Easy to build with simple tools and they’d work real well as board racks.

hope that’s of use