Where to reinforce my flexy repaired board?


So I’ve just fixed a big delam patch (like 1/3 of the deck, just behind center. It’s been a big project, just took it out in the water, very exciting, BUT, when I punch through the heavier whitewash as I’m paddling out, I can feel the board go WOMP and flex a liiiiittle more than I’m comfortable with. I’d like to reinforce it somehow with some strategically placed glass, and looking for some ideas!

Also negotiating the following:

  1. Had a lot of burn through with the sanding I did on the repair, especially near the area where the repair meets the old board.
  2. The board seems to be “tail heavy” - I can still catch waves, and I think it makes it really responsive when turning (fun), I kind of like the way it responds. I might be okay with a little more weight in the front but don’t want to go too far.
  3. In general don’t want to add more weight than necessary.

Thoughts on how to reinforce? I have 4oz cloth.

There’s a whole lot you haven’t said about how the repair was done, and no photos of the process, but my initial reaction is that if the repair is completed, and you have fiberglassed the white deck repair area and are still experiencing some unwanted flex, you should glass over the white deck repair area one more time, overlapping the edges about 2-3 inches all the way around, and then feathering.

If you’re using 4 oz. cloth, this might add maybe a half pound, which is minimal on a board of this size.

This is the area and shape that is normally glassed with a deck patch anyway, as it is where you mostly stand while riding (probably the reason for the delam in the first place), and it would afford the opportunity to add a little tint if you wanted to make the repairs less obvious.

To me, the flex as you describe it is kind of a red flag that your board may be prone to buckling in the future if you don’t address the issue.


Totally - swaylocks limits me in photos as a noob poster. Waiting for that sweet sweet upgrade!

In an offline chat, someone also said just to reinforce the rails, as that’s where most of the strength/stiffness comes from anyhow. Curious to hear your (and general) thoughts on this as well.

Good to note that the weight would be negligible. Thanks for the insights and advice Huck!

I didn’t really know that about the photos, but I’m still learning this new platform. The site has gone through a lot of changes over the years, but it has remained a great resource for learning, for teaching, for researching, and for being inspired.

“reinforce (only) the rails, as that’s where most the strength/stiffness comes from anyhow”

This doesn’t really make any sense to me. Just logic says the area weakened is the area where glass was removed, and that’s the area requiring more glass to strengthen the board. Yes, the rails are a factor in stiffness, and if you run the new glass 2-3" past the edges of the repair, you will get the rails involved.

As I also said, the problem originated from a deck de-lam, which likely would have been avoided if the exact area of the de-lam had had more fiberglass, hence why would you pass up the opportunity to strengthen the deck in such a way as to avoid or at least postpone having to do this again?

The weight of repairs and glassing is a factor of how much resin is used, this is why I talked about avoiding pooling in the other thread. I can’t say how much weight will be added. But I can say I have added a new layer of 4 oz. fiberglass over an existing longboard, and both times I glassed top and bottom, and overlapped the rails, so one new layer, and two on the rails, and both times I added just 2 lbs.

Also, I mentioned the opportunity to add some tint to the lamination of the deck repair. While your repair looks good, it also looks very obviously repaired, and if you ever decide to sell the board or pass it along to another, adding some color will make it look less repaired and help your resale value.

BTW, I have done plenty of repairs over the years to mashed or de-laminated decks, to the point I have even gone to adding a wood inlay to a surfboard deck to strengthen it where the rider stands.

I buckled the deck of a 10-2 many years ago. I left it on the rack for years before fixing it because I was so upset. When I did fix it, I stripped the whole deck lam from the cut lap, then I added “love handle” channels along the deck rails to add strength. It definitely helps.
I don’t ride the board much these days because it was a tandem board for my daughter when she was a kid. She’s 30 now.
I have small fish that has a really bad delam on the deck and when I do fix it, I will do the same, sand the cut lap area until I get down into the glass just before touching foam, sand the rails up to the edge of the tuck until I see glass, strip off the deck glass up to the cut lap, put in a new deck inlay (glass or fabric), then another layer of clear glass all the way around to the edge of the tucked rail.
The glass along the rail is what keeps your board strong. If there are any tear outs on the foam, fix that before doing the deck inlay. I use a heat gun when I strip off the glass and it works well. I have been able to get a complete side of the board off cleanly and I keep the old glass skin to make templates.

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Very cool sharkcountry! So if I understand correctly, the goal is to cut away the deck as cleanly as possible, keep as much of the original foam as possible, and then replace that deck slice exactly with whatever reinforcement up to the same level as the original deck (let’s just say 2mm of resin and glass). Finally glass it all in. I hope I understood that correctly?

Questions: what do you mean by love handles, and what do you mean by channels? Is it a separate cut of glass from the final glassing step mentioned above, or is it that you wrap that large piece of glass all the way around to the bottom?

Fiberglass or carbon tape to reinforce the rails should stiffen the board for sure. Less lamination, less weight.
Think “channel beams” — in this case, more of a U-Beam.
You could apply a thin resin coat over current rails using this method.

Hi Jin,
I’m not sure if this is any helpful , but I have the slight feeling that the good core info is getting lost between the written lines here. I have by no means the experience like Huck, Stoneburner and Sharkcountry , please take this as an comment from a noob who thinks he understood at least something.

Like Huck said it’s hard to tell from the picture what we’re talking about here , I see a snapped/repaired board and a smaller repaired area behind center.

“… area and are still experiencing some unwanted flex, you should glass over the white deck repair area one more time, overlapping the edges about 2-3 inches all the way around, and then feathering”

The overlap is important. You want an overlapping area ,as large as possible ,that allows some kind of interaction between the fibers to reinstall some of the structural integrity to the board. If the overlap is too small there is no strength.

“… to the edge of the tuck until I see glass, strip off the deck glass up to the cut lap, put in a new deck inlay (glass or fabric), then another layer of clear glass all the way around to the edge of the tucked rail.
The ( continuous fiber) glass along the rail is what keeps your board strong”

Be aware that on a longboard you are cutting at least 2 layers of 6 ounce cloth out of the deck and id be concerned about using just one layer of 4 ounce after you filled it flush with something.

Glass wants to lie flat, so stay away from sharp edges.

I think you are aware of this basic stuff anyway so sorry for the smartassing, but I was worried you would go for hard edge channels now :wink:

For the channels you could have a look at the older hot seat thread with Dane Hantz , he explains this very well.

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Look at Stretch Surfboards, they have a deck channel (groove) everyone calls love handles. They help increase the rigidity of the board by adding extra strength near the rails. Basically they create a complex curve that is harder to break than a flat surface.
I showed how I do them using a small piece of pipe in a post from about 2015 or 2016, but everyone has their own style.
Once the inlay is added and cut clean, I add a second layer of clear around the rail till it reaches the bottom. You can go further, but sanding it smooth will probably take most of that off.

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Basically, your love handle/deck groove is a recessed channel beam (U-channel).

Rail channels, also called deck channels, or “love handles”, will act to minimize flex, but there’s a couple things to consider. One, the original post indicated that the flex wasn’t a design problem with the board per se, but more a result of the repair work that was done. If thats the case, then rail channels shouldn’t be needed to bring the board back to its pre-repair level of rigidity.

I would add the extra glass to the repaired deck, with the overlap, first, then see if more rigidity is called for.

I have done several boards with rail channels, and I think they’re great, especially on bigger boards with fatter rails, as they really make grabbing and handling the board much easier (hence the name love handles). Ideally, rail channels are added in the shaping stage, before glassing. Now, they can be added later (to an already glassed board) and I have actually done that on a few boards, but its not a simple project, and is more suited to someone with shaping and glassing skills, IMO. So for a newbie to shaping and glassing to add them to an already glassed board, it could be a bit much. I don’t think the initial issue of flex resulting from a deck repair requires rail channels, or even re-glassing the rails.

If the flex problem was created by removing glass from the deck de-lam, then it should be fixable by replacing the glass on the deck, with some overlap required to tie the new glass to the existing, as I mentioned and as jspr explained. We don’t know the details of the fiberglass repairs done, but it sounds to me like it was just an inadequate glassing job on the deck repair.


Don’t have to make love handles/deck channels.
Just add carbon/s-glass/e-glass tape to the rails, sufficiently wrapped — extra layer(s) of rail glass re-enforce/stiffen the board.
No extra shaping or deck glass needed — assuming original repair was done correctly.
Several have posted rail re-enforcement at Sways.

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This has been so helpful everyone! Thank you all! Learned a lot about channels, new glassing techniques, materials, and priorities (getting enough overlap with the old glass)

I think where I went wrong in the repair was not having enough overlap on the rails with my initial repair. I have 2 layers of 6oz glass, but the overlap was only about 1-2”, and didn’t wrap around completely. As I blended in with the existing glass, I also think a lot of the new material was removed in that overlap.

The plan now is to do another layer of glass over the entire repair that will wrap all the way around the rails, and give me enough leeway to blend without removing too much glass. This would also give another layer of glass to the deck, which is probably a plus. Had some burn throughs anyway so the extra glass will probably help.

I think the channels, while cool, may be a little beyond my current skills. Will try the easy route and see if that provides enough strength to where I feel it won’t buckle. Can go back to reinforce rails if this is insufficient. Thanks everyone!!

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Please keep us posted, post up some pics if you are able. Let us know how it goes.

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