Patch Failure
 

Any body else ever have a patch fail ?
I changed a tire, used the same tube, didn't realize it had a patch. Pumped it up and off I went. Got a flat. Thought it was because I forgot to screw the valve back in, so I filled it up again. Got a flat, again. WTF? So I took the tube out, and put some air in, and saw that the patch had failed, and it was easy to take it off. Never had this happen before, except for tubes my wife patches.
Just wondering.

I expect the area around the puncture wasn't cleaned adequately before the glue was applied. If the tube has dirt, water, powder or mold release still on it the patch will not bond. That's why sandpaper is included in the patch kit and rubbing off the area after sanding is necessary.

I've had one of those peel-and-stick patches fail, even after properly prepping the tube. I threw the rest out and restocked with the reliable glue-on ones.

The peel and stick dry patches aren't as permanent as the older vulcanizing patches. However, since air pressure holds the tube pressed against the tire they usually stay put pretty effectively.

OTOH, if you used a classic patch which you "glue" on with stuff from a tube, the likely problem is failure to read and follow instructions. The stuff in the tube isn't a glue, but a vulcanizing preparation, and has to be allowed to dry completely before the patch is applied. If you put the patch onto wet or semi dry glue, it won't bond properly.

Permanent patches: Only failure was when I had a new patch overlapping the edge of an old patch.

Self-adhesive patches: In warm weather, they last about a week. In cold weather, they last about a mile. I still carry them for quick on-the-road patching w/o needing to remove a wheel. But they are strictly a get-home measure, not a permanent fix, regardless of marketing claims.

YUP.

Also, it's hard to get a proper seal on a patch when the puncture is along a seam or right up against a valve stem.

I had a vulcanized patch fail once. It was on Sunday. I must not have prepared the area very well. It had about 600 miles on it before the patch gave up.

Never.
90% of a proper patch job (or any job involving adhesives) is very careful surface preparation.
A few extra seconds here is time saved on a re-do.

A little Visine bottle with alcohol in it is good for cleaning the patch site after you rough it up.

I do not patch on the road. I replace the tube, then patch at home at leisure. Never had a patch fail this way.

+1
Best plan.

Same here^
I'd say if you are using a tire patch kit (not those sticky backed versions) and you are having patch trouble it is how it was prepped if done right they stick very well.

I have never had the peel and stick glueless patches fail. I use Park brand, and completely sand the site of the hole.

Not allowing the glue to dry sufficiently is another failure mode. It's likely the primary reason.

+1, I still take a patch kit with in case I get more than 1 flat.

Park's first glueless patches (GP-1) were very failure prone as the backing was much less flexible than the tube and the "squirm" between them caused the bond to fail sooner or later, usually sooner. Their revised verasion (GP-2) are supposed to be better but I've never tried them. Cleaning the area thoroughly and allowing the glue to dry adequately (+1 to cyccommute) has made Rema patches 100% reliable so why change?

Well I am surprised by this thread.....I thought it was common to have a 50% patch failure rate. I go to great lengths to rough (expose fresh rubber) clean (brush away rubber granules), and always allow the glue/solvent to dry. I do this back in my garage at leisure.

The things that might be affecting my low rate of success is:

-Cheap no name patches I bought?
-Old glue/solvent (sometimes a little thick, does this matter?)
-Old patches (do they age ?)
-I buy the cheapest tubes money can buy !?


I really like the idea I have heard here before of buying quality patches (rema tip top) in bulk, but I have this fear that they would go bad on before I could use them.

My FLAT rate (not patch success rate) has gone down considerably from early years, since I buy brand name tires, keep them properly inflated and do not have too many challenges (broken glass, goats heads) Though I have learned to stay out of the grass in the fall, we have sand spurs and on two separate occasions I have gotten multiple front and rear flats from crossing a grass median!

If you allow the glue to dry on the tube properly (the longer the better), I'd expect a 1% failure rate to be excessive. Even when patching over patches, I doubt that I have one failure in 1000 patches. Even then the only time I've had them fail is when I rushed the job.

Patches, by the way, don't age in my experience. Glue will dry out if the glue tube is pierced but the patches will last for a very long time. Even if the glue is thick, i.e. had the solvent evaporate, it should still work.

A properly applied patch will outlast the tube and is bonded at a molecular level to the tube through vulcanizing and is not glued.

Failure is caused my improper preparation in just about every case of failure.

Like others I carry a spare tube and a patch kit even though flats are a rare occurrence in my life and I worry more about the cement getting old from non-use.

Had my first flat of the season last weekend and the last one was at least 10,000 miles ago...

Thanks for the feedback, I am going to invest in better patches and solvent/glue.... and apply the advice for better patch technique. I have been recycling allot of tubes (much more than I want). It has prompted be to buy tubes in bulk. Any body need some thorn proof, schrader 20" (451mm)

If a tube is properly patched, should it be ok to keep riding on it until it finally gets a flat again? I've only used the patch when I got two flats and used my spare tube up. I was under the impression that a patch was only an emergency fix to get you home, but with the numbers of flats I've been getting I'd rather patch and keep using the tube.

Gorilla Tape works great - even better - than glueless patch kits that cost $5 or $6. I patched a road tube with it and rode for over a week before I needed to properly repair the tube with a Rema kit.

Just about anything works in a pinch. I used to use Band-aids for emergencies, but can't anymore because they changed to breathable (micro-perforated) strips.

One good thing about a failed patch with vulcanizing glue, is you can be sure the surface is now clean. Assuming you let the glue dry enough, if the patch failed you may not have cleaned away all the release agent or other contaminants. If you replace the bad patch with a new patch the odds are it will be a permanent patch.

If a tube has been patched with a vulcanizing patch kit, you can keep on riding on it, just as if it was a brand new tube.