Jeff Liebermann wrote:
I've been in the repair biz for too long. I can tell because some of
the adhesives in my disorganized collection are at least 10 years old.
Yesterday, I had to glue an HP Envy m6-1125dx laptop hinge mount back
together after the left a lump of something on the keyboard, and
closed the LCD lid. The weak spot was where HP had glued the metal
attachment point for the hinge to the aluminum cover and plastic
frame. Miserable design and crappy workmanship, but I can't complain
because that's why I'm still in business.

I tried cyanoacrylate adhesive, 5 minute epoxy, 24 hr epoxy, RTV,
Elmers contact cement, and Duco cement. Nothing worked. The glues
either remained tacky after 24 hrs, hardened in the tube, or crumbled
when stressed. Hardening in the tube is an obvious sign of old age,
but I've never had Duco cement turn to powder when it hardens.

Yes, I cleaned off the old glue between applications and carefully
removed any residue and oils with acetone.

So, I walked to the nearest hardware store, and bought a few
overpriced tubes of epoxy and other adhesives. Right now, I'm trying
some J-B Weld KwikWeld (sets in 6 minutes). Watching glue dry didn't
seem very productive, so I thought I would ask a few questions instead
of Googling for the answers.

Few of the package, bottles, or tubes, show an expiration date for
either shelf life, or shelf life after the bottle is opened. The
exception is RTV, which is formulated to harden in the tube after
about 1 year whether new or opened. Gorilla Glue seems to harden in
the tube about 3 months after the tube is first used.

So, in your experience, what are the approximate shelf lives of these
common adhesives?
Devcon or Ace 5 minute epoxy
Devcon or Ace 24 hr epoxy
Devcon or Ace Plastic repair epoxy
JB-Weld KwikWeld
JB-Weld
Gorrila Glue (water activated polyurethane)
Elmer's or Weldwood Contact Cement
Duco cement
RTV sealant
Barge Cement
Super Glue (cyanoacrylate)
Super Glue Gel
Elmer's white glue
Elmer's wood glue
Elmer's Craft Bond Rubber cement

Back to watching the glue dry... Thanks.

In my experience the rubbery, not really hardened epoxy has been due
to inadequate mixing. I've found that you need to really mix the epoxy
well. For even a small amount I mix for at least 30 seconds, sometimes
more. As for age, as long as the resin hasn't solidified/crystallized,
it still works.