Sergio makes a keen observation here. I've encountered butyl tubes in recent years that won't abrade cleanly, but rather the surface smears a bit, due to some odd formulation. This is fairly common now, and results in patches not sticking well, even with fresh glue.
This problem became particularly obvious when I started carrying glueless patches. Some repairs have held for years now (really, even with the Park patch cut into quarters) yet some won't last even until the air is pumped in!
I suspect either too much plasticizer solvent in the butyl, or some mold-release substance having permeated the surface. There is also the possibility that tube manufacturers have deliberately changed the formulation away from one that provides easy repairability, to one that is more stretchy or easier to make, and at the same time I am noticing higher prices for tubes in the past year or so. If tubeless tires continue gaining market share, this could be the milking of an old cash cow, no?
David "conspiracy theorist" Snyder
Auburn, CA USA
> On Fri, 25 Nov 2005 j.mccoin@comcast.net wrote:
>> Back in the"Day", everyone I knew who rode tubulars, and that was
>> EVERYONE,
> patched their inner tubes with a piece of inner tube from a dead tire.
>
> Yes, everyone!, myself included.
>
> However, recently I have run into many failures in patching inner tubes,
> whether of tubulars or clinchers, that good old way.
> I have a suspicion here, folks: some present day tubes are made of
> rubber which is a lot more difficult to be vulcanized.
> Is it really so, also for you?
>
> Sergio
> Pisa
> Italia