longboard repair question

I have a twice-snapped board that I picked up and it was in the middle of being fixed for the 2nd time.

THe middle had alot of small filler spots on the bottom, some resin and no cloth yet.

The top had a layer of cloth and laminating resin but no sanding resin so the cloth was visible and just not complete.

I put a HUGE triangle of 6oz cloth ( from west marine D’OH! ) and glopped on a bunch of marine resin ( D’OH!! )

then i put sanding resin on top and bottom and sanded it as well as i could, just to get it in the water.

it still has a huge delam bubble on the top and a small spot at the fin that was taking on water.

last night i sanded it with a drill and 4" circular attachment. OH BOY. i cut down to the foam in a couple places, probably because i’m not sanding right.

is the circle supposed to be flat while sanding? should i have a bigger/thicker foam pad so it will stay flat easier?

A bigger problem, when they put the resin on, and when i laminated, the board wasnt level on the bottom. it’s not SUPER bad but it does have kind of a “waist” or dip all thruout the middle, where the snap was/is.

is there a way to level this without adding too much weight?

Do i have to cut out the cloth and resin, put some spackle on the foam to reshape it, then put the cloth and resin back?

or can i level it with resin+qcell?

If i remember, i’ll get some pics and put them up.

The other problem i have is i’m short on $$. I have @ 1/4 gallon of sanding resin and a few oz of catalyst and 2 pieces of 6oz cloth that will fix the tail bubble I already cut off.

For the deck delam, i was told to just cut it open and fill it with some resin, maybe qcell mixture, and seal it back down with the original decking.

thanks in advance, i’m sure this is all over the place, welcome to my brain.


Whoa! If what I’m picturing in my head is what you’ve done I don’t think you will be happy with the results even if it’s water tight. Without pictures, nobody here can tell you exactly what to do. Because the board was snapped you need to reinforce the stringer among other things. If you look through the archives I am sure you will find similar repairs, they are not easy to do if you want to do it right and you’re gonna need more materials than a couple of pieces of 6oz and some resin.

yea i’ll have to get pics up tonite. There was some reinforcing done on the stringer in the way of two slim pieces of wood, one on each side of the stringer.

I think there was foam missing somehow and when they put the first coat of resin on, it left a low spot in the middle and thin spot on the rails as well.

I’m tempted to cut it all out, re-level the foam and then give it a new middle but that’s more $$ than i have right now and more $$ than i spent on the board to begin with.

initially i was only hoping to have it water tight. Now I’m thinking i would like it water tight and a little bit lighter which is why i started sanding down some of the resin last night, into the heavy marine resin laminating job i did. Not to mention the diamond patch i put on there was probably way too big by maybe 24" or more, total.

i’ll get pics tonite.

here’s “Frank” in all his glory (short for Frankenstein)

He’s been smoothed out with 80grit, too smooth in some parts, down to the foam. I’m not sure what i’m going to do with the fin box area since i had to remove some brown water-damaged foam. What do you suggest i use for a filler? I’m thinking cabosil+resin might be too heavy? How about light weight spackle?

i know he’s not pretty but at this point, since i’m still learning - repairs and surfing - i would be happy with something lightweight and watertight to help me catch more waves.

you can see the big bubble here

There’s a lot in the archives about fixing broken boards, most notably Bill Barnfield’s photo instructions. Same for fixing that delam, but in my opinion you’ll have to cut it out. Filling large flat, deep areas with resin/filler mix isn’t a good idea (like peel-back on a break or your delam). It will crack easily and weighs a lot. Spackle isn’t a viable filler here either. For around the finbox per your photos, resin+cabosil is OK. For large areas down to the foam, the best way is to layer cloth in. Bevel the edges of the good glass so that you can blend in the fill-glass easily. Over this, you still need a larger overlapping cloth lam. Check the broken board threads for the overlap width of cloth over the break. To do this level of repair, 80% of the job will be sanding and you’ll need more than a drill with a sanding disk. Get a Harbor Freight rotary (about $30), and I hope that you are using a dust mask and respirator.

i have a dust mask with a tiny respirator on the front but i think i need to get ahold of a real one.

i’m not sure if i want to take it all off just yet. i will patch the tail and the bubble for sure but as for the middle of the bottom, i think i will make it water tight and see how it rides.

if it’s riding well enough, i’ll save up and strip the middle out and patch the foam then re-cloth and glass it.

i’ve seen alot of “snapped board repair” threads but the only issue i have with those boards and mine is that whoever did the initial repairs on this one did not level the foam before they started laminating.

so now my leveling/evening process would have to be post-glassing. like you said, i think that would be too brittle.

if i was to cut all the glass and cloth out, down to the foam, say just on the uneven portion of the bottom, what would i use to bring the foam back to level? some of that pour foam or maybe the expanding spray-insulation?

then - layer of 6oz cloth against the foam and a layer of overlapping 4oz cloth ontop of that? (covering all of the 6oz and overlapping the “good” glass by a few inches)?

thanks for the help

also, i just searched “harbor freight rotary” expecting it to be a sander. I have a dremel, would that work ok for taking glass off?

i’m sure this has been asked… what kind of cheap sander is recommended?

i also did a search and am not sure about, when using a circular sander, if the entire disc is supposed to be in contact with the surface at all times?

ie. rather than sanding at an angle?

The safety equipment is very important. A respirator is a twin-cartridge mask for glassing. A dust mask is just a simple filter (maybe with a exhaust valve) for sanding. You also need gloves for glassing, and the proper handling/mixing/disposal of resin.

OK, we got a way to go on tools and technique before you move on with your repair, more than can be answered on the forum. Please get a detailed book on board repairs, like “The Ding Repair Scriptures” or “The Art of Fiberglass Surfboard Repair” at a surf shop or online. Read thru it, whatever you don’t understand check the archives or post the questions here. On the sander, the one you want is on the Harbor Freight website # 92623-8VGA ($39). The repair book will explain how to use it. If you just make it “watertight”, it will probably just break right away because there isn’t enough glassing to hold it together.

i’ll have to add the book, and probably the sander, to my christmas list.

i guess in the meantime i’ll have to go with what information i’ve found here on swaylocks.


PM me your e-mail address I’ve got an early christmas pressent for you (sorry not the sander)


PM me your e-mail address I’ve got an early christmas pressent for you (sorry not the sander)

pm sent, thanks

i sanded the heck out of the bottom over the last few days and then put a coat of sanding resin on the whole thing.

as well as i patched the tail delam, using boat resin that i think i over catalyzed. the first layer of cloth came our really hot and kind of brown and kicked REALLY fast. oops. it’s a learning experience.

i’ll sand down the last coat a bit, carefully since i’m out of sanding / hot coat resin, and it should be just about ready for the water. i still have to fix that bubble on the deck. i might try and get to that later in the week. pics will come shortly.