I tried a couple on old boards last night. Laying them up was none to difficult. When I did a strength test this moring, however, I was able to pull both of the loops off with a minimum of effort.
I sanded down the gloss and scuffed the surface with 60 grit so I could get a good bond but the glass loops didn’t seem to stick to the deck.
Well, hummm, first off if you pulled them straight up from the deck the’ll bust off really easy. But thats not how they are supposed to get yanked, right. Second if you just let it sit over night, then pulled on them, they are still way too green to be yanking on. So it seem you know how to make loops, its a strength issue. I kind of over kill them so they look cool. 8 pcs of saturated rope around a wax coated dowel, 2 pcs of 6oz cut in an hour glass shape over that. Sand, polish,gloss. You got the sand the deck thing down, 80 grit is fine as long as you give the resin and glass plenty of bite to attach to. I attached a picture of one of my loops for ref.
I use surf wax on the dowel, but you could wrap it in wax paper, just use something so the resin won’t stick to it. I lay the dowel on the deck of the board and put the fin rope over that (laminating resin), once it kicks off I pull the dowel and put the 6 oz hour glass patches (laminating resin) over the loop and on to the deck to secure it down real good. Hot coat, then you sand the whole mess smooth and flush. Gloss / polish.
You don’t say how much glass you used or how you spread it out. Let me suggest my crude approach…
I take apart a square-ish piece of 6 ounce glass about 8 inches on a side, lay the strands parallel. I lay the dry strands over a pair of pencils wrapped in masking tape, and wet out with lam resin, usually end up using one finger to smooth things out.
It’s important to spread out the ends of the strands as much as possible, to increase the bond area. I spread 'em about six inches wide at the end of the strands. Since you didn’t describe your process maybe this was the problem. 60 grit sanding certainly should have been rough enough to provide a good surface.
That attached pic on another post is a very nice looking leash loop and shows how a good job should be done.