I’m getting into a big delam repair on an old Becker LC-3 and have removed a big patch of glass from the deck. The foam below was all rotted and crumbly, so I routed and sanded the foam down to fresh material, about 1/4" in. I’m now thinking I need some new foam sheets to glue in before fairing out the deck and reglassing- I’m having a hard time finding a source for thin sheets of PU foam (maybe a slightly higher density like #4?) to do this… any ideas from the experts here?
I’d consider an inlay of balsa planks. You might even be able to scavenge some PU foam from an old blank, mow it down to maybe 3/4" and glue that in, then shape to match your original contour.
I wouldn’t do a resin fill of any type because of my concern of it cracking the first time if gets stressed.
Flexible époxy + lot of microsphere : volume resin, 4 to 5 volume micro, give thick dry past à bit hard to spread but really easy to Sand. Wet foam with resin first. Lam over. Do it on many boards, pu eps surftech, it works.
I was thinking balsa or cork may make sense- I’d only need 3/8" or so thick. I’ve never used pour foam but the mess and the re-fairing seems like it would be more hassle.
Also I’m trying to decide whether I should use poly resin or epoxy for the reglassing- I assume poly would have a better bond to the deck where I’ll overlap it?
I completely forgot about cork - that’s probably easier to do than anything else. If you’re buying cork you could also do an exposed deckpad with it, too.
I’d definitely use epoxy over an inlay.
That looks like a very cool shop! Any chance you are in California? ‘The Craft’ in San Luis Obispo had some urethane sheet foam last time I was in. They’ve started branching out in to composite and boat building materials as well as surfboard making supplies. They don’t have an online ordering system but I’m sure they’d take your call. http://thecraftglassworks.blogspot.com/
Thanks- my shop is in RI- I have a small architectural design and metalwork business. I’m super impressed with all the help and feedback here- such an awesome community! So I’m thinking that I’ll seal the exposed foam with some poly resin, seal some cork sheet as well, bond the two together, then shape the cork and do a 4 oz cut lap and 6 oz free lap… anything wrong with that idea?
Do you think the cork underlayment available at Home Depot is fine for the job? Corecork seems to have limited availability and I’m not clear on what makes it different. I’d probably glass over it so as to have the structural deck intact and just wax it.
Craft stores sell cork in a roll that is 2’ x 4’ and about 1/8" thick. They also sell 1’ squares that can be up to 1/4" thick. I’ve seen 2’ x 8’ rolls in California at a craft store. They keep it by the chalk boards. It used to be about $11 a roll here in Hawaii, but I saw it recently for about $15 or more. It isn’t the same as corecork, but under glass it should be fine. Corecork seems to have a very uniform sizing and a bit tighter binding, the craft store stuff is not as good, but I’ve used it for rails.
I almost bought a huge roll of cork underlayment from Lowes once, but my wife was with me and I decided not to. It was a clearance sale, $25 for huge roll that would have been way more than I could use, or fit in my car.
If you use cork, just epoxy it to the foam. Lemat’s epoxy filler idea sound interesting too. Don’t leave that straight line across the back. Make it a V shape.
I positively despise PE resin for any use. I’d use epoxy for both the core-to-blank bond and for the glassing. If you’re using generic cork other than Core Cork I’d consider sealing it with epoxy+microbaloons first, fair the surface out and then glass over that in epoxy. That way the cork won’t drain your lamination. I think that repair might outlast the rest of the board.
IMO. diluting epoxy with a filler is kind of defeating its use as an adhesive. You can do a cheater coat on both surfaces that you want to bond, let it set up a bit to the point where its still a little sticky then hit one side with some fresh resin. If you really want the cork to stick to the foam use some lightweight fiberglass non-woven veil - that stuff practically grabs both surfaces when its wet out. I use veil when I bag veneers on and once that sets up you just about can’t peel the skin off without ripping the foam out. I use veil when bonding plywood to fiberglass panels when I’m making fins - different materials with different flex, so the bond there is critical.
Incidentally, if you use cheater coats prior to bonding the two surfaces together go easy on that final wet-out. You only want to use just-enough to stick these surfaces together, otherwise the excess gets squeezed out and causes problems. Like, use a brush or roller to paint it on, not a squeegee. I learned that lesson the hard way.
The generic Cork roll I bought felt really heavy. I’ll have to weight and measure it but basically a ~1/4" full length deck pad felt like it doubled the weight of the board
