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This might get lengthy…but hopefully it will be worth it.
Last October on a nice Seneca southerly I noticed the sensation of the water undulating against the bottom of my feet as I neared planing speed while out of the straps. It felt as if I as feeling the water agains the bottom of the board, right through the board. I headed in to discover I had a squishy deck just forward of my back straps on the left and right sides of my board.
Some research (talking with Freaky G and the inter web) informed me that I had compacted the foam core of my board after repeated impacts/pressure on the board. Their was now air space in there. I was lucky though (sort of) as it seems that I had not cracked the glass and wood lay up and no water had gotten in.
I got good information that the board would be best fixed by removing the soft area and doing a new lay up etc….. It would be time consuming, labor intensive, and not cheep to fix my 2004 Mistral Screamer. I thought hard about doing that, and Geoff even offered to guide me on it.
Smart money says another board is the best bet and that my board owes me nothing. Ride it till it dies.
I didn’t want it to die, but I didn’t have tons of cash to do a pro fix.
So what I settled on after searching around the internet and talking to Ken Jones (who knows a good MacGyver repair technique when he sees one) was Gorilla Glue White. Gorilla Glue is a water activated glue that expands with moisture (a reaction causes gas to be released and bubbles to build in the glue before/as it hardens). I of course was not going to use it as a glue so much as I was going to use it to fill some empty space inside the board buy adding some water and letting it expand to fill the cavity. I’ve heard that micro balloons added to epoxy can do something similar.
So what I plan to do in this post if describe the steps of what I did to fix the board, and provide photos of the work.
I have already completed the fix but have yet to ride the board. I have my fingers crossed, and feel pretty confident about the repair.
wd
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Preparing the board.
I drilled holes through the skin of the board to just past the periphery of where the deck felt squishy. One exception is on the port/left side just under the back deck pad. The board was a little squishy on the edge of that pad. That was going to be messy so I am hopeful the glue was able to expand in that direction.
I was initially concerned that the glue may expand too much (be uncontrolable) and bubble the skin of the board. That did not happen luckily as the deck was a sandwich of glass, carbon, and wood (as best I can tell) in this area and had enough strength itself.
So here is a pic of my experimenting with the Gorilla Glue in an effort to understand what it may do when the water was added. I found a good video on Youtube about controlling the cure and hardness of Gorilla Glue with vinegar and baking soda, but ended up just using water.
One of the concerns raised from the video was that the bubbles would not be uniform and would affect the strength of the structure of the foam. So below you will see plain glue with no water, glue with drips of water mixed in ahead of time (the very white blobs), glue sprayed with water from a spray bottle on the top only and then glue put on top of sprayed water, and then sprayed again. They all did different things. The most uniform was with the water mixed in, but it was too squishy and didn’t keep its shape. The one I ended up liking best was a couple sprays of water directly on top (upper right corner of the paper plate, with black arrow). Somewhat uniform bubbling, and hardened fairly solidly with some flex still.
I also did an experiment where I drilled holes in a paper plate after putting the glue on another plate below that. I sprayed the holes on top mimic what might happen inside the board.
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I taped off the area surrounding the repair and away I went. The below pic is of what the glue looked like after expanding. I ended up using the spray bottle and hitting it from a bunch of different angles. Some holes didn’t bubble much. I am going to make a bunch of assumptions about what happened or didn’t happen in the board.
The holes that didn’t bubble much may not have gotten enough water, or perhaps they didn’t have enough glue. Each hole ended up filling/curing to the board deck level though. I may have used too much glue in the holes that bubbled a lot. What matters most to me though is that the deck was/is firm and I did not detect any places where the deck shape had been deformed or the skin released from un-dented areas perhaps caused by the expansion force of the glue.
The below pic shows the board during sanding prep for getting a layer of fiberglass cloth. When the prep was complete I used Acetone to clean the area before glassing. I ended up digging out each hole an 1/8th of an inch and filling them with marine tex.
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So for this stage of the repair, I leaned on what I learned in discussion with Gary W. who does some SUP repairs on the side. I ended up using Marine Tex and fiberglass loth to finish off the repair.
Any kid of research on the web among board repair purists would say that these techniques are unproven at best. Another layer of glass at this spot may or may not change the flex of the board. There is no guarantee that any kind of bond occurred between the gorilla glue and the rest of the inside of the board. I’m hopeful.
The below pic is of the holes filled with Marine Tex, and the cloth tacked down with some Marine Tex before I started spreading.
Glassed and curing.
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The final stage of this repair was mostly superficial and appearance related. Tons of sanding and smoothing resulted in a nice uniform surface where I made the repair.
Gary had raised a concern about how I planned to protect the area against the heal dents happening again, and my hopeful answer to that question is by covering the area with EVA deck pad. I bought single density deck pad from NSI. The pad had a 3M sticky backing, so I again used Acetone to be sure the sanded surface was foul free. I was concerned about how the board would look following the repair, so here is me spending too much time designing a stencil for the deck pad:
I’d say my labor and attention to detail was worth it though as the repair seems to flow with the pads on the deck. A delicious Lock 32 Brew Mule Fuel Double IPA was necessary as I reviewed my work.
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Hi, is Your repair still solid after 4 years? I have soft deck problems in same area and next to mast track as well.
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Hello Ahto,
Yes, to the best of my knowledge the repair is still holding up quite well. I have had nothing to indicate otherwise to me. I have had 5-10 sailing session on the board each year since the repair and it still delivers everything I have grown to love about it.
Another local sailor did a similar repair on one of his boards this fall. Maybe he will chime in on his success. He recently posted a homemade nose guard in the non wind section of the forum.
Keep us updated if you go for it with this repair.
Good luck!
Wd.
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Did you just injected Gorilla glue into the holes from glue bottle and after that sprayed water on it? Or it’s better to firstly mix Gorilla glue with water, inject into the hole and spray some water on it? I understand, that Gorilla glue works better on wet surfaces.
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Ahto,
As I recall, I injected the Gorilla Glue into the holes from the bottle first and then sprayed the holes with water once the glue was inside. Try this on a plate or disposable surface first, to get a sense for how the glue rises for a given amount of water. The photo I shared above with all of the different results was first covered with another paper plate with holes in it and then sprayed from above. I think I may have even counted how many shots/pumps of water I used on the test so that I could do roughly the same on the board. I think I also tried to spray at an angle occasionally so that the water droplets got under the deck of the board onto the glue.
Responding to your question about mixing, in theory that sounds like it may aid uniformity, but as I mentioned in a previous post above, it was structurally less impressive. It was quite uniform, but was more “squishy” than other tests. I believe in the previous photo it is the foamy looking blob. If you are curious about spraying surface first, then applying glue, and then spraying more I would just set up a test. The worst of the area that I filled was 3/8 of an inch deep and what I did worked fine for that. I always felt that if I did not use enough glue, I could do another round on top of the first…the glue really grows with water.
I am not a pro at this, but would suggest maybe starting with a small part of the back of your board, and see how that responds. The spots around your mast base are quite large and would be more important to get right (have the process figured out) in my opinion. They get a lot of non planing force from your feet.
Windydoug
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