If you ever wanted to know what is going on when a hull delaminates, this should shed some light.
That is interesting.Thank you Dan.
m.
Dan,
You are a wealth of information!
Do you know what the two different layers are made from?
The inner layer looks fairly soft.
I meant to add a comment--I know many people are talking about injecting resin or something into the hull to bind the foam to the fiberglass, but the surfaces just don't seem to be able to be prepped well enough. In all the hulls that I have seen cut up (and it has been a few) the 'foam' does not seperate cleanly. There is a thin layer still attached to the fiberclass shell and there is a gritty or powdery residue all over the place between the layers. It seems to me that you really couldn't get a good bond between the two due to the unclean surfaces!
Thanks for the photos and information Dan.
Jack
Injecting epoxy does work.....If you do it right and early.
If a layer of foam is still attached to the fiberglass, then I would think that it is not an adheasion problem. I would guess that the shear stresses in the foam exceeded the strength of the foam and the dust is from the two surfaces rubbing together each time the skin flexes. This is only a guess but you test the idea by cutting out a strip from an area that is not seperated and bending it back and forth several times to see if it will cause a failure similar to what you see in the picture.
The delam shown in your pic is quite uniform along the upper surface. As you noted, this is not usually the case. When I cut my 6 inch deck port holes (to also allow me to repair the hull delam) on my H16, the foam had separated from the upper layer in some areas, and the inner layer in others. The inner glass weave was about 1/2 an inch lower than where it would have been if not damaged. (It looked like a 3D map of mountains and valleys). It would have taken a lot of epoxy to fill in all of the space between the layers!
Mark
1976 H16 sail #19857
Hi Dan,
Please be advised that epoxy on polyester does not always work.
If my information is correct your hobie is made of polyester so use polyester.
See also the attachment we used polyester to repair an A-cat from a friend.
And that hull is currently looking brand-new.
The picture attached is when we took it apart to repair the top deck and some “studs?” inside.
Success
Re my successful repairs of seriously delaminated decks: you MUST remove just about all of the crumbled old brown foam from the underside of the top skin, and from the old foam surface too. If there little left of the stiff white polyurethane foam, replace the foam with new.
If the inner fiberglass cloth skin has fallen off too, the whole thing has to be replaced. Ick! This is what happens after years of sitting uncovered on the beach, full of water!
If so, can one 1. Bend the foam, 2. Epoxy cloth to the concave underside and get it to stick, 3. Glue it into the hole in the deck, 4. then put a new top skin on? Answer- Yeah, but it will (probably) look like a Goat's butt. Big job too.
You should post this on the H16 forum as I think some of the H16 sailors there would be interested in this topic and pics.