A two months ago a i got myself a $50 Hobie 9’2 on craigslist problem was that it had a 7 inch delam on the deck. I purchased with the idea of getting in some practice on ding repairs and delamination. I went on-line and did some research and followed the instructions from the surfline forum this is what I did:
Polyester resin.
2) Catalyst, and a small measuring cup to use it with. Methyl Ethyl Ketone Peroxide is its name, and when added to resin it causes the stuff to gel, then harden.
3) Fiberglass. (Be careful with this stuff: it can be a skin irritant.)
4) Polyurethane foam.
5) A roll of tough masking tape.
6) Sandpaper. Having several grades of paper on standby can be useful. Get a really coarse one (about 40-grit), a medium (150-grit) and a fine wet-and-dry (360-grit).
7) A mixing container. A sturdy cardboard cup, a plastic bowl or an old ice-cream tub will do. It should be clean and dry. Use a small wooden slat as a mixing weapon.
8) A Stanley knife, or other heavy-duty tradesman’s blade.
9) Added extras: Q-cell, a fine powder which mixes with resin to create bulk without added weight, is great for helping fill smaller dings.
A week after I finally took it out. It rode amazing but after 30 minutes the delam part that I thought I fixed was all cracked and let in some water. it looked like shattered glass. I went ahead and let that completely dry and patched it up again. After finishing it with a hot coat and drying for two days I pressed with my thumb , pretty firmly and the darn glass cracks again!!! wtf am I doing wrong??? I really enjoyed the 4 or 5 waves that I rode and want to get it fixed but this project is driving me bananas! ! ! please help.
You list what you needed for the repair, plus a lot of unnecessary stuff.
But, you did not spell out the process you used to fix the delam.
Proper approach is:
Drill a hole on one side, just through the glass. Drill a second, or even third hole, on the opposite side. Inject catalyzed resin into one hole until the gap is about half filled. Place wax paper over entire area. Park a heavy object on top to spread the resin and push the loose glass back down. Without bleeder holes the resin won’t spread well. If you time it right any excess resin that oozes from the holes can be removed easily with a blade edge, after the resin gels sufficiently.
I have no idea what you did, but it sounds like the delammed glass is floating above the foam. So it will just keep cracking.
what I did was, with a right angle grinder I carefully sanded down the delam area and removed the glass. I then sanded the foam and proceed with the instructions above.
You sure as hell don’t need a right angle grinder to fix a delam.
You say you used “the instructions above”, but you did not list any instructions.
You don’t need to sand the foam to fix a delam. If you have exposed the foam enough to sand it, you might as well just put a couple of layers of new glass on it. You went at this the wrong way, made more work than needed, and got a bad result.
I sanded down the foam and made it smooth and leveled. I refilled the area with resin and q-cell and let that harden(2 days), then I sanded that down and layered 6 oz cloth with resin , sanded that down, did a dry coat . took it out and got the cracks. I read that using the “puncture” method makes the board much heavier when the delam is pretty significant.
if you post pictures and discuss your procedures and ask questions as you go, its a lot easier to get help and answers. Now the project is finished, no pictures of the process, limited description, a lot tougher to get any definitive answers. just sayin’.
The “puncture” method, when done correctly, would add less weight than what you did.
So, given your description of the process you used, you went way beyond SOP for a delam and just re-glassed the bad spot.
Something is wrong with the glassing you did if it’s cracking under normal use. My best guess is you loaded too much resin in the cloth.
That makes a brittle repair. You may have also mixed too hot and that also makes it brittle.
I totally agree! I was unprepared and frustrated and at work when I posted this morning. My procedure is pretty much the way I described it prior: Using the sandpaper edge on a disk sander, I carefully sanded the glass around the edge of the delaminated area until i get close enough but not piercing to the foam. I then used a Stanley knife to cut the delam glass. I sanded down and mixed my sanding resin with q cell and added the catalyst , made a layer to fill in the newly exposed area. let that dry. I sanded the new resin down flush to match the surroniding surface. I increased to fine grades of paper to get a smooth finish. Layer some cloth . I am in San francisco and the weather has been below 63 for a the last few months. Would too much catalyst cause it to crack? The bottle indicates to add 20 drops of hardener per ounce of resin if the weather is 64 and below. Thanks for your time.
Can you post some pictures? Might help to see what we’re talking about. Also any pictures of the repairs being done, if you have any. You mention you followed the advice on another forum, wondering did you ask them over there too, just curious what they said. Not familiar with that forum, but I know there are plenty of smart / experienced / helpful people here on swaylocks. Sammy’s method is a new one for me, love to see pics of that one too! I am always learning here.
swaylock is the only site that i registered as a member. It was surfline.com that had the advice but now I cant locate the link. I did not take any pictures of the process but I can take one when I get home.
Resin+qcell sets up really stiff and can be brittle. It will never flex as well as the foam to which it is “bonded”. So what happens when the blank and the rest of the glassing flex more than the repair? Something has to give and it will always be the more brittle and stiffer repaired area.
Sammy explained how to rebond the original glass with the original core - that will be the cleanest and most efficient way to handle a simple delam - so long as the underlying foam hasn’t gotten soaked and deteriorated.
Others will surely disagree, but I believe resin-based fills are best used with extreme moderation. I only use them for small dings that have very little surface area. For large repairs I’d much rather scarf in a piece of scrap foam into a deep repair and reshape it to the original form; then glass over that. Limit the fill to the cracks between the original blank and the repair section.
Big repairs are why you always keep at least one old board around rather than throw it away. Once in a while that donor foam will come in handy.
Agreed, gdaddy. Resin + thickener is only good for small stuff, especially where there’s lots of stress or compression. Even on rail dings bigger than about 3/4" I will go with a foam wedge/plug every time. When I was doing ding repair on a regular basis I was always recyclng parts of broken boards to cut up for scraps and fillers. If I saw guy about to discard a broken board I’d take it from him. I’ve recycled fin boxes, leash plugs, etc from ‘dead’ boards.
“I sanded down and mixed my sanding resin with q cell and added the catalyst , made a layer to fill in the newly exposed area. let that dry”
Sanding resin has wax & styrene added to it. Probably should not be adding fillers to it or additional layers of cloth over it. Should have used laminating resin in those steps
So it looks like I did this all wrong. How can I fix this error? I really like the board and the handful of waves I caught that day where fun. It felt like a great board and want to fix it so I can get it out there. Can we start from the beginning please? Much appreciated.
crazyeddy that was an excellent video, I watched the sequel too. Makes me wonder, tho… Does that high density foam come in thin sheets like that? And is two layers of 4 oz. really gonna be enough on a longboard deck like that?
