A friend's Mega Cat has softened in the deck on both sides of the mast track - likely from years of him pressing there. He's hoping I can help him keep his beloved board on the water. It claims to have a "honeycomb sandwich".

Our present plan is to cut out the soft deck, spray some can foam in there. Sand it flat. Roll out some 5 minute epoxy from a tube with a bread rolling pin and smooth it on. We'll redo the non-skid with some surf wax.

Just kidding. I'm pretty proficient with repairs in general. I'm worried that the foam is too compromised just to do a foam injection and that we'll need to cut out the deck and bad foam; and rebuild. I'm trying to get a sense of what we should do for the new deck that would be equivalent to the existing structure. Do we do a modern PVC sandwich, wood veneer, just lots of layers of glass or something else?

Also does anyone else remember off hand the epoxy well suited to sticking to plastic skin? iirc, West System has something that sticks better than average? The website search function is a bit clunky for looking that up.

Spoiler alert! Is it really worth fixing, it's pretty old? Nothing likes to stick to that plastic skin. The repair is not easy at the best of times on a normal board let alone this one with its odd construction. It will look bad at best. That kind of board construction is usually quite tough and if it's not waterlogged may keep going as it is. The most I would try, is as you suggested, injecting something to fill the voids. Unfortunately fixing it properly, it's like putting lipstick on a pig. It's not even a board that you would fix purely for the practice. Sorry about that

Pvc would be the go, dont even try with nomex honeycomb .
West systems gflex is what u refer to but you still need good prep on the plastic and its still not permanent bond at that interface like it would be on normal skin.

I am with Imax though.
And thats before we factor in the cost of Gflex.

jusavina said..

Paducah said..

Our present plan is to cut out the soft deck, spray some can foam in there. Sand it flat. Roll out some 5 minute epoxy from a tube with a bread rolling pin and smooth it on. We'll redo the non-skid with some surf wax.

Add some sugar with the epoxy and you won't have to use surf wax.

Trying to cut down on my sugar intake. Would Splenda or stevia work? That paragraph was in jest - thought I'd give Mark and the other skilled board mavens here a bit of anxiety.

Mark _australia said..
But will add too - dont use single pack spray foam or gorilla glue type thigs for many reasons.
Get the 2 part stuff.
But again if foam needs to be built up that bad, geez is it worth it in that board.....

I'm a big proponent of the two part stuff as well even for my modest messing about. Thanks for mentioning that in case someone else runs across the thread and was even for a moment contemplating the spray stuff.

Technically, the repair doesn't bother me as I've done other stuff as or more technically challenging; and have the tools and materials. Cosmetics don't matter either. However, the comments about the bond with the skin are what concern me. Good raceboards are pretty rare now days in my area is more the issue so spending a few hours on this are probably worthwhile as it helps a buddy stay on the water. And for racing here, a raceboard will outperform a decent foiler 75-85% of the time as the wind is too light, inconsistent and we're doing short upwind/downwind courses. I say that as someone who loves to foil, too.

Sounds like we should try to do the injection instead and revisit the issue if it seems the issue is persisting. I appreciate everyone's input greatly.

Paducah said..
Also does anyone else remember off hand the epoxy well suited to sticking to plastic skin? iirc, West System has something that sticks better than average? The website search function is a bit clunky for looking that up.

west System G flex. I used it on an old starboard formula board with tufskin (plastic skin) and it worked great. To prep it you sand it with 80 grit? You can also use flame oxidation (this is what I did).
www.epoxyworks.com/index.php/flame-treating-plastics/

To be cont'd... we ran out of syringes and had to order more. Injecting two part foam under the deck and will seal up the holes with micro balloon bog.

jusavina said..

Paducah said..

jusavina said..

Paducah said..

Our present plan is to cut out the soft deck, spray some can foam in there. Sand it flat. Roll out some 5 minute epoxy from a tube with a bread rolling pin and smooth it on. We'll redo the non-skid with some surf wax.

Add some sugar with the epoxy and you won't have to use surf wax.

Trying to cut down on my sugar intake. Would Splenda or stevia work? That paragraph was in jest - thought I'd give Mark and the other skilled board mavens here a bit of anxiety.

I have to admit that until the rolling pin and wax, I was about to cry reading it

same :))))

Impressive save. Speaking of feathering the edges. Is is important to avoid sanding thru to the fiberglass on the borders? Or is that necessary to get a very smooth transition?

What's so wrong with spray foam/PU? Yes, it's open cell, but so is polystyrene. Not arguing - more interested as I've used it to fill/glue polystyrene in cores before.

The gap filler spray foam is indeed very inconsistent (and not very strong).
The adhesive style spray foam (e.g., for hanging sheet) is more consistent and certainly much stronger. I use this to cut out and reglue delaminated sections, and it works OK.
Liquid PU is good for gluing in replacement foam chunks.
For drill/inject, pour foam seems like the only option, but it's a hassle for an occasional repairer.