: . . . But it occurred to me,
: what about "5 minute epoxy?" Can I use this really fast curing
: epoxy for bonding jobs like this?

Yes. Most of these glues set up in 5 to 15 minutes, so they won't run and drip too much, even if not thickened. Their strength develops over the next 24 hours typically. So, clamping time may be anywhere from 15 minutes to 24 hours -- depending on how much you've bent the wood you are bonding.

Even if not a marine grade, the joints are going to be sealed under your glass and a maraine grade epoxy, so these glues are no worse than the Titebond you have been using.

If you are in a real hurry, I have used some 90 second epoxy to repair my glasses frames. They say to mix it for 30 seconds. After that the potlife can be counted in a matter of breaths. If you don't have the glue in place by the time you have inhaled 10 or 12 times, it has kicked, and you might as well go mix another batch. About 50% of its maximum strength in about an hour, so it is very strong, very quickly.

Interesting thing I found about the real fast epoxies. You have to be really careful to not spill or drip. They are not in a liquid state for very long once mixed, so by the time you reach for the solvent or rags to mop up a mess, it is already getting hard and resistant to solvents.

: I bet it would fill the
: gap better than the yellow glue, and it would cure much faster
: so that I can get the clamps off and move on to the next step.
: Is it strong enough for this?

Certainly strong enough, and gaps would not be an obstacle to drying and/or hardening. Again, though the brand and the temperature ou are working in will determine the time you'll need to keep the clamps on.

: For that matter, what about other jobs? For example, filling in
: gaps in the filleting where I filleted between the stitches. Could
: I get 5-minute (or 10-minute or 60-minute) epoxy, thicken it, and
: use it to fill gaps?

Yeah, but it would be expensive, and if you really wanted to save time there are better techniques. For example, you could fillet the seam with a thickened epoxy, then before it set up you could go over that with your strips of glass cloth or tape, and wet that out. In one day you've finished your fillets and taped the seams, reduced the need to sand and reshape the fillets (squeegeeing the glass on top moves the still-soft fillet around to a smooth shape)

Hope this helps

PGJ