It seems to help make a really good bond. I've tried old pieces of plain inner tube + heat with mixed results.

I'm surprised that no-one has answered this. The substance was always
marketed as "rubber solution" and came in a toothpaste-type tube.

That is actually _de_vulcanizing solution. The vulcanizing happens after it dries away and is then clamped together, often with heat.

I've had good luck using rubber solution with old latex swim caps. The swim cap is half a mm thick -- all you need or want for most punctures -- and pretty gooey to begin with after being degraded by chlorine, sun and O2. Latex makes a great bond to a butyl tube. Even after the latex cracks from "dry rot" it still holds air!

But if you want something thicker then the dedicated patches seem to work much better than just old pieces of butyl inner tube.

I'm guessing that one side of the patch is pre de vulcanized maybe made of "bonding gum." Bonding gum is what they put between the carcass of a tire and the tread of a re tread.

What got me going on this is I found some really cheap inner tubes that would rupture if you looked that them funny. Yet, cut up into patches, they made really great bonds. One guess is they never really vulcanized the rubber in the first place.

Bear with me on this one as I positively suck at materials science.


Bret Cahill