"Pylls, Barry" > wrote in message
...
> I have an all-metal travel mug (the ones with vaccum between inner and
> outer walls) whose rubber bottom is peeling off. I was going to use
> 5-minute epoxy to paste it back on. I'm somewhat certain that it is
> inert, but just wondering if anyone knows of any issues e.g.
> substances leaching into surround water when it is being washed in hot
> dishwater. The reason for this caution is that I know that some
> house-hold pails are not recommended for use in creating large
> quantities of food for that reason (leaching). I epoxy is not a good
> adhesive, what is?

There are several basic catgories/types of adhesives, with varying
characteristics. No one adhesive is best for all applications.
There are about five or six adhesive types. Some are strong, some are
flexible, some hold better in heat, some are water resistant, some penetrate
deeply into the substrate.

All will dissolve and/or soften to varying degrees when immersed in hot
water, including the one that originally held the base onto the mug. Some
barely dissolve, others will wash off.
The problem I see with your application is that when immersed, water gets
into the rubber at the bond face and interferes with the bond, as well as
softening the bonding agent itself and allowing peel. And water stays in the
rubber for a long time after being taken out of the water.
So you should not immerse the glued parts in hot water if you want the
foot to stay put.

My guess is that the foot was originally attached with a glue similar to
Scotch 77 spray. You could clean the pad and base and use that spray on the
parts to reattach, and keep it out of the water and it would probably be ok,
or you could use a better adhesive, as below:

Epoxy has excellent tensile strength and is somewhat flexible relative to
some other types, but having used it a fair bit in engineering applications,
in my experience it is not the best for your application.

A favorite for problem attachments where flexibility, water, and
temperature is involved, and especially where rubber is involved (and even
where failures of other glues are happening) is "Shoo-Goo."
It is a flexible RTV type that sticks well, seals well, is fairly
forgiving of application, and takes some abuse. It does not have the tensile
strength of epoxy, but it has better toughness and is more pliable than
epoxy. And I think it has more "cleaning agents" in the mix than do other
RTV adhesives.

Matching characteristics and a clean dry substrate is the key to a good
bond. Throughly dry the base and the pad. Then clean the pad and the base
liberally with rubbing alcohol so the alcohol goes in and displaces the
water, and then it let dry in the open for a day or two (to get the moisture
out of the rubber.)
Wipe surfaces lightly with rubbing alcohol. Apply a film of Shoo-Goo to
the base and the rubber, being sure to get it out to the edges.
Then roll the rubber on, using one-edge-first like a pie crust top to
avoid air pockets, and press it on (not hard) all over with your thumb or a
roller to force out any air and get good contact. Wipe the edges to get a
neat filled edge. Let it cure 24 hours.

And avoid immersing the mug in hot water.

fwiw....




>
> Thanks.