I would give the job to your local cobbler.
Marc St. Martin Livermore, California USA
-----Original Message-----
>From: Mitch Harris <mitch.harris@gmail.com>
>Sent: Apr 22, 2009 3:57 PM
>To: CR discussion list <classicrendezvous@bikelist.org>
>Subject: [CR] How to re-glue shoe uppers to plastic soles?
>
>I have several pair of on-topic plastic soled cleated cycling shoes
>where the leather uppers (toes or heels) have separated from the hard
>plastic soles.
>This has usually happened to NOS shoes after just a few rides, so I
>don't think it's a matter of use or wear, but just old glue from the
>70s/80s losing its grip on shoes that sat for decades in the box. My
>riding climate is very dry so this hasn't been the result of soaking.
>Also my use of these shoes is gentle, I think. I never take more than
>a couple steps off the bike in these shoes, and my pedal stroke is
>such that I pull back and up with heel up rather than pulling up on
>the uppers into the toe clip and strap. So I don't think I'm ripping
>the uppers off by sheer force.
>
>I bought some glue from my local cobbler that he recommended, followed
>his directions for prep and clamping, and the Sidi upper did not
>re-attach to the sole. This glue reminds me of tubular cement, so is
>probably a type of contact cement and there may be better kinds of
>glue to try.
>
>I'm considering attempting this with urethane glue, the kind that
>cures with moisture, because they are usually good at attaching
>dissimilar materials I've found. The the end results can be messy so
>I'm saving this for a last resort.
>
>Gorrilla glue is often recommended for sport shoe repair stuff
>(telemark boots, etc.) but I haven't tried it. Is Gorrilla Glue a
>contact cement or urethane glue?
>
>Also considering taking the shoes back to my cobbler for him to glue,
>but if his glue didn't work for me, I doubt if it would work for him.
>Maybe he has a better clamp to use with his last.
>
>BTW, of all the brands of shoes that gave way, only Vittorias never
>have. Two pair are solid after lots of miles.
>
>Mitch Harris
>Little Rock Canyon, Utah, USA