Pete,

Hmm..I'm seeing the same things. Thinking back on it, I've had about 4 failures, and if I remember correctly, there was water (humidity) present at least 3 times. I think the other time was epoxy that spent its first time (dry) in very hot sun.

Most things we build tend to get glassed, and this puts a thick enough barrier in place that we never see any moisture/heat problems. Our hooks are only epoxy-coated, and not as thick of barrier. Incidentally, I've seen pretty poor performance on epoxy-coated wood that isn't then varnished--even out of the sun.

I wonder if maple is a bad wood to use. It is such a dense, tightly-grained wood, I think very little epoxy saturates either edge or end grain, and the mechanical bond is fairly shallow. Anyone use mahogany hooks--any failures? Stacked ply like Ted is using seems to be a good solution--okoume might bond even better than birch (more open grain).

250 psi: I think Nick posted that in response to my mention that I had a failure in underlying redwood. Certainly we're having failures well below that with our hooks.

Shawn

: So, wait for the sucker to pop, then re-glue with CA?

: I'm sticking with my heat/humidity theory for now: The problem seems to go
: away when I re-coat with even a thin coat, as long as it finally appears
: glossy when it has hardened.

: My failures have been right at the wood/thickened epoxy boundary on the
: bottom of the hooks. No wood failure was evident. Each failed hook had at
: least a small area somewhere on the endgrain surface that was not glossy.
: I take that to be an unsealed spot, even though I have no scientific
: evidence; it just seems to be acting that way. There's no way I'm getting
: anywhere close to a 250 p.s.i. tension loading with my arrangement.

: Cheers,

: Pete,
: in Snohomish