thread I know nothing about road bikes,
but I've used special tape that goes between the tube and the tyre, that is made out of special goo, that reacts to any air being expelled from the tube, and cleverly seals the gap.
It's like those MTB inner tubes you get that have liquid gack in them that solidifies in the area of any puncture.
permalink Yeah, that is kind of what the Weldtite stuff was like.
It served dual functions - had less chance of a puncture (because there was a barrier) and attempted to close up punctures - fine at 30PSI with a Swampthing, probably fuck all use at 110PSI in Gatorskins.

If you are as fat as I am then 20mm tyres are not worth the effort, they end up being as wide, if not wider, by the time I compress them.