Depending on the plastic, you may have pretty good luck with Barge cement. The key to getting a good bond is proper application. Thin coats to both surfaces, and let each surface dry overnight (don't press them together (keep them pried apart, in fact)). After each surface has thoroughly dried, re-activate the glue with a heat gun or a very concentrated hit from a hair dryer...try to get both materials (not just the surfaces) quite warm before you push them back together. I've fixed quite a few shoes of various sorts with this technique...if the plastic is a very low surface energy material (Teflon or Delrin), you're going to have troubles, but it'll hold with simple nylon materials for quite a while.
The polyurethane glues (e.g., Gorilla Glue) work pretty well in this application, too. Do some reading about correct application, though....you might have issues with the tendency for it to expand while curing (which can be controlled by clamping between the upper and sole). The other thing is to keep an eye on the areas where it may ooze out, because it will often foam up there a little and is difficult to remove after it's hardened.
Report back with your results, please.
Scott Minneman San Francisco, CA - USA
-----Original Message----- From: firstname.lastname@example.org [mailto:email@example.com] On Behalf Of Mitch Harris Sent: Tuesday, November 27, 2007 9:10 AM To: CR Subject: [CR]How to re-glue shoe uppers to soles?
What procedures and what glue would you use to reglue uppers to plastic soles?
Noticed before that there is some cobbler expertise among list-members, and I have several pair of cleated cycling shoes whose leather uppers have pulled away from the plastic soles. On some it's the toe, some the heels, but about half the upper pulls away. In all cases these were pretty lightly used NOS shoes. No abuse, no rainy rides.
I could take them to the shoe repair guy who is expensive but does a good job with stitching repairs and re-soling, but this seems like it should be a simple matter of knowing the correct glue (?).
BTW, it was early 80s Sidis and Maresis that did this. Dettos and Vittorias never have, despites decades of hard use. Leather soles shoes never have either.
Thanks, Mitch Harris Little Rock Canyon, Utah
p.s. Thanks for all the helpful responses to my Simplex QR question yesterday. Now if I could just find rubber hoods for the Simplex QR levers.