AK wrote:
:On Tuesday, September 17, 2019 at 11:21:10 AM UTC-5, David Scheidt wrote:
: Frank Krygowski wrote:
: :On 9/16/2019 11:10 PM, David Scheidt wrote:
: : patrick wrote:
: : :Just got back to riding after 6 months off and had a couple of problems
: : :with patches. Using the usual abrade/clean - alky or acetone then lay
: : :down the glue, wait to dry , apply patch and wait a bit. Tried several
: : :and had the patch peel away under a bit of stretching of the tube.
: : :thought there might be something amiss with the adhesive and the result
: : :with the different brand of valcanising fluid was the same. The patches
: : :themselves were not sticking to the alum base sheet and the plastic was
: : :intact on the peel way.They felt as flexible as new so I don't think the
: : atches themselves were bad but I can't speak to the cold vulcanzing
: : :agent that's supposed to be activated by the fluid in the tube Going to
: : :buy a couple patch kits before I commit to another couple boxes of rema
: : :small/large patches. Again 6-8 yr old patches out of the box (stored at
: : :ambient temps SoCal- hottish summers but the restf the yr pretty mild -
: : :coastal). Thoughts?? Thanks Pat
: :
: : The inner (tube facing) surface of a patch consists unvulcanized
: : rubber and a vulcanizing ultra-acclerator (usually a zinc
: : thiocarbamate, but the details are propertietary, of course). The
: : ultra-accelerator is supposed to be inactive, until it's activate. In
: : normal usage, the vulcanizing fluid contains an activator (usually a
: : thiazole), which activates the ultra-accellerator, and voilla!,
: : instantly vulcanized repair. Heat in storage can set the patches off,
: : as can exposure to various chemicals. The box of patches I've got
: : says I bought them in 2011. They, and the bottle of vulcanizing fluid
: : (dated 2013) worked fine when I used them a few weeks ago. But
: : they've been stored either at my office or my baseement, neither of
: : whcih get hot.
:
: :That's a _lot_ more chemistry than I've ever understood, but I agree in
: rinciple with David. I have patches that qualify as ancient -
: articularly, the oval Rema Tip-Top ones that are almost two inches
: :long. Whenever I finally use up all the round patches in a box, there
: :are a couple of those left over. They sit around for years in my
: :basement drawer, but I've never had one fail when I've finally found a
: :use for it.
:
: there are times I wish I had a box of those:
: https://imgur.com/gallery/wKGLIvd
: https://imgur.com/a/MhRgmcA
:

:When the hole is that big, you need to throw it away.

Why? Both those tubes are still in service, and both hold air.

The little one was the tube a tricycle. It's a weird size, and has a
hooked valve stem. It came out of the box like that; fixing it let my
daughter ride her new trike on her birthday, instead of sometime later
when a replacement tube could be found. She rides a real bike now, so
the trike is in the attic, but the tire had air in it when I put it
away.

The bike tire one was done almost five years ago, and has acquired a
couple more patches, in different spots. I don't remember if it's in the
bike or if it's the spare at the moment. The flat was caused by a
brake pad rubbing the tire.

I have patched holes I could put my entire body through -- those were
on earthmoving machines, not bikes, but still. On tubes like that,
you can cut out and replace the valve stems when they fail, using
something like

https://gemplers.com/collections/wor...r-tr-218a-220a


:I thought I was cheap.




--
sig 91