On 9/17/2019 3:13 PM, wrote:
On Tuesday, September 17, 2019 at 12:31:13 PM UTC-5, AK wrote:
Frank Krygowski wrote:

: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.


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

I thought I was cheap.

:-)

Andy

The big bicycle tube patches are useful when you happen to get two small holes side by side and can only use one patch to cover both small holes. Think of a pinch flat where you slam the tire into the edge of a pothole. And the pavement edge compresses the tube and tire against the rim edges. This can result in two small holes about an inch apart. One big long oval patch might work to repair both holes at once.

Agreed, that's what I have used them for. But it's been a rare event.

The other use (just yesterday!) was a super-slow leak in the rear tire
of my around-town three speed. It required pumping only every five or
six days. I finally got around to fixing it last night. When I blew the
tube up to about 4" diameter and held it under water, an existing patch
was seeping a 1mm bubble every five seconds or so. (This is very
unusual. I almost never have a patch fail.)

I laid one of the long patches over the old patch, covering the edge
where the seep occurred. I'll know in a week whether that was successful.


--
- Frank Krygowski