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.
I think I would attempt some form of PVC sandwich repair. Not sure what gets the best adhesion to the skin.
Good luck, I used to have a 96 model, but had to sell it because of a house move.
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
Select to expand quotePaducah 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.
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.
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.....
Select to expand quotejusavina 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. 
Select to expand quoteMark _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.
Select to expand quotePaducah 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
Select to expand quotePaducah 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/
Select to expand quotePaducah 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.
Looks like a great board worth saving if only for the moving bits.
I have done a lot of repairs on ASA epoxy skinned boards with no issue as long as a good sanding comes first. The old thick ASA Bic and F2 were difficult, and that was before the magical Gflex.
For encouragement here is a pic of my house of cats. The white one weighs 13 kg and had split rails, a mate just sanded off and painted the skin and it is really dry and stiff. Just had some careful carbon cboard cassette surgery.
The other is freakishly mint with original flaps and has a couple of rail dings needing touch up. I just like to feel it each night at bedtime. Same weight.
After the LT got me longboarding again, these and an F2 Lighting WC have got me wanting to live forever and not really caring about foiling. Sorry. It's just the glide and the go in any direction any day of the week that gets me. Did I say that the Cat keeps up with many short boards reaching in many conditions?
Select to expand quotejusavina 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 :))))
Latest update. Repaired crease in rail with 3 layers of glass (2x4 and 1x6oz) as well as spot on deck, skimmed on some bog and now awaits sanding and some primer. Board owner wants to restore graphics as a project. I must say the injection holes were a pain to fill as it was too easy to have a bubble under the fill that then wanted to float up. Took a few tries to get them all filled properly. Major mistake was using bog at standard thickness for first pass or two instead of using something more runny that would let the air bubble float out. The nasty bits near the track are from prior repair attempts. I can't take credit for them.
fwiw, peel ply made the rail repair so much easier. When I pulled it off, I had a really nice smooth repair that needed minimal additional tweaking beyond feathering in the edges of the glass repair to the board skin. Easier than I thought it would be. Hope this cat stays on the water a few more years.
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?
Select to expand quotethedoor said..
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?
I don't know why I'm replying as the amateur in the room. I'd say no. Cosmetically, I guess you could do either. Structurally, the important work being done by the glass is over white part that's showing underneath. A taper reduces the chance of creating a stress point of having a stronger section (where the glass and original construction overlap) abruptly transition to the rest of the board. In retrospect, I could have confined the taper just to the "white" section but the purple is just a decorative vinyl cover. I probably took the taper too far.
I appreciate the kind words.
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.
Select to expand quotedambat said..
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.
Pour foam has a very consistent internal structure. Spray foam doesn't. It's like bread with big air holes
If you have to sand back or reshape, you end up having to use a lot of bog to smooth it out. In my case, pour foam is liquid before it starts to react so much easier to get into a syringe and inject into the board and seep into the original EPS. Additionally, the consistent structure of pour foam gives me higher confidence that I have a uniform core under the skin.
I just used some can foam to seal an air gap under some gypsum board (drywall). It does that really well
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.
