Bicycle Mechanics - Poor patch quality

I have patched bike tubes for 40 years. Often I remove a flat and find a tube with 6 or even 7 patches that worked well until a new flat occurred.

Now however, I find patches are failing. Possibly this is due to a bad batch of patches, but I doubt it. I often find a patch that does NOT leak around the perimeter, instead it leaks right through the middle of the patch, as though the patch material is made of paper. I am not talking about the self adhesive plastic patches here, I am using the standard patches with glue etc.

Anyone else notice this? Or did I just get a few bad batches of patches?

Oh yes, I also notice that cyclometer quality has substantially gone downhill as well, but that's another post.

oldbluejeans
iambaughman.com

I use Rema patches exclusively and have never had the patch itself fail, only the glue bond occasionally when I've tried to patch over a seam in the tube. Any chance that the item (glass bit, metal sliver, etc.) that caused the original flat is still in the tire and poked through the patch too?

I use Park glueless patches. I have never had one fail for the life of the tube.

I use Park glueless patches. I have never had one fail for the life of the tube.
I may give them another try. The first version (GP-1) years ago was known to fail frequently since the patch didn't stretch with the tube. I tried them and my experience confirmed their poor reputation as they were unreliable for more than "get-home" use so I never used them again. Maybe Park has improved them to the point of reliability.

I may give them another try. The first version (GP-1) years ago was known to fail frequently since the patch didn't stretch with the tube. .

The most-common problem with patches that slowly fail is that the patch allows stretch, which thus also allows the glued part of the tube to also stretch into a state of tension as the inflated tube fills the tire.
With the tube itself stretched in tension, the patch remains pinned against the inside of the tire casing by air pressure, but the tube can pull away from the patch, starting at the puncture hole, since air can only get between the bonded layers at the hole.
Eventually, as it slowly peels away, the tube is pulled into a flat surface, like a drum head, until the "drum head" diameter reaches the edge of the patch, at which point the air rapidly escapes.

The "speed patch" product, which introduced the idea of glueless patching, used a thin closed-cell foam sheet which was elastic, and these patches were known to fail reliably minutes or hours after each repair.
The subsequent Park product used a less-elastic plastic sheet material which by comparison was many times more inelastic, which helps prevent the tube from pulling away from the patch starting at the hole.

BTW, today's inner tubes are highly variable in terms of their patch-ability, with some tubes having a slightly "gummy" surface rubber which is extremely slow to abrade away cleanly, and all types of patches (glued and glueless) are challenged by it's Teflon-like adhesive properties.
By contrast, tubes from back in the day would typically abrade cleanly, with no balled-up, sticky rubber having to be sloughed off continuously as it was being created by the sanding action.

I use Rema patches exclusively and have never had the patch itself fail, only the glue bond occasionally when I've tried to patch over a seam in the tube. Any chance that the item (glass bit, metal sliver, etc.) that caused the original flat is still in the tire and poked through the patch too?

***
You are correct HillRider that this could be a cause. I always check the inside of the tire though, so I am not sure that applies here. Where do you get the Rema patches?

Where do you get the Rema patches?
Rema patch kits (a plastic box with a small tube of glue, sandpaper and 6 or so Rema patches) are available at most bike shops and from Bike Tools Etc. among many on-line dealers. You can also buy them in boxes of 100 for shop use or sharing with friends.

Here is Bike Tools Etc.'s web page for the Rema kits and the boxes of 100 patches are shown on the second page:

http://www.biketoolsetc.com/index.cgi

Yep, Rema patch kits are not the same as the cheap generic ones. I've had a few Road Tubeless tires that I simply could not patch with a generic/Park patch kit, yet the original Rema worked fine.

For road tubeless, Rema sells a patch kit with a different glue.
Ideally, the tire makers and Rema would fully cooperate on the issue of compatibility, but I don't know if that's actually the case, as it is with tubeless tire and rim makers co-generating standards of compatibility.

The most-common problem with patches that slowly fail is that the patch allows stretch, which thus also allows the glued part of the tube to also stretch into a state of tension as the inflated tube fills the tire.
With the tube itself stretched in tension, the patch remains pinned against the inside of the tire casing by air pressure, but the tube can pull away from the patch, starting at the puncture hole, since air can only get between the bonded layers at the hole.
Eventually, as it slowly peels away, the tube is pulled into a flat surface, like a drum head, until the "drum head" diameter reaches the edge of the patch, at which point the air rapidly escapes.

This may be true with patches that use 'rubber cement', i.e. the very cheapest generic patches. However, it's not true with cold vulcanized patches like the Rema. Cold vulcanizing goes beyond a simple adhesive bond and becomes part of the tube. The new bonds formed are almost indistinguishable from the original rubber. They won't peel away fromn the tube because they are part of the tube.


BTW, today's inner tubes are highly variable in terms of their patch-ability, with some tubes having a slightly "gummy" surface rubber which is extremely slow to abrade away cleanly, and all types of patches (glued and glueless) are challenged by it's Teflon-like adhesive properties.
By contrast, tubes from back in the day would typically abrade cleanly, with no balled-up, sticky rubber having to be sloughed off continuously as it was being created by the sanding action.

I've not run across any tube that is unpatchable and I have tubes from many different sources. All tubes, even the old ones, have a mold release compound on the outside. The tube couldn't be removed from the forming mold without it.

The key to a successful patch is more involved with the quality of the patch...*COUGH* Rema...and allowing the glue to dry properly than with the tube itself.

A leak through the tube sounds like the offending object hasn't been removed.

The only time(s) I've seen a proper Rema failure was due to the the puncture being larger than a couple of mms, and the patch eventually began to aneuryism/rupture. I stated in another thread where I'd "doubled" over a patch. This is when I did such, sucessfully. It's now SOP this type of puncture.

Mind y'all, Ccyco's admonition. For this reason I don't "grate." Besides, doing so scores the tube.
Who desires that?
Chemical buffer for me, or scraping+spit with a razor then alcohol cleanse if I puncture a 3rd time--which does happen...
...Or come-up with a thought-to-be-repaired spare that won't hold air :troll: *but only a little*

Remas (by me) have failed, due to operator error. This is why I have come to prefer them: they can be removed--carefully-- and another placed saving the tube for another ride series.

I do though let the patch "cure" for as long as possible. Usually more than a day (if I'm fortunate some weeks....).

Lastly, when in doubt, double down a second coat of glue. Might help, can't hurt.

The only time(s) I've seen a proper Rema failure was due to the the puncture being larger than a couple of mms, and the patch eventually began to aneuryism/rupture. I stated in another thread where I'd "doubled" over a patch. This is when I did such, sucessfully. It's now SOP this type of puncture.

I keep a stock of Rema patches in different sizes, so bigger tears are usually not a problem either, unless next to the vent. The repair kits tend to have just a couple of sizes. The larger patch sizes need to be bought separately and they might not be there at LBS-es.

Rema patch kits (a plastic box with a small tube of glue, sandpaper and 6 or so Rema patches) are available at most bike shops and from Bike Tools Etc. among many on-line dealers. You can also buy them in boxes of 100 for shop use or sharing with friends.

Here is Bike Tools Etc.'s web page for the Rema kits and the boxes of 100 patches are shown on the second page:

http://www.biketoolsetc.com/index.cgi

Do patches get old and fail to properly adhere? I ask because lately I've had a couple that didn't seem to hold. They were a couple patches that I got out of an old kit because I needed larger ones. Could have been operator error, but my patch jobs usually hold.

I ask because a box of 100 Rema patches would probably take 15 years for me to use up. The ones that seemed not to work were probably 10 years old, although they were probably not the highest quality to begin with.

OBJ, Thanks for the post. I to use to have no trouble patching tubes but now I have no confidence. For me I patch exactly following the directions. Maybe right away or several days later, I install the tube and begin to fill with air. At about 60 psi or so, the patch will let go. I mean it's as if the tube streches but the patch don't. I have not tried Rema or Park Tool but will try both and both glued and glueless. The only patch kits sold here are Slime which is what I use. I also use quality Bontragger (sp) tubes from lbs.

Do patches get old and fail to properly adhere? I ask because lately I've had a couple that didn't seem to hold. They were a couple patches that I got out of an old kit because I needed larger ones. Could have been operator error, but my patch jobs usually hold.

I ask because a box of 100 Rema patches would probably take 15 years for me to use up. The ones that seemed not to work were probably 10 years old, although they were probably not the highest quality to begin with.

The layer of rubber that contacts the tube is a mixture of unvulcanized rubber and one of a few suitable vulcanization ultra-accelerators. There's an activator in the glue, which activates the ultra-accelerator. The patch then vulcanizes itself to the tube. Patches can fail from age if the vulcanization gets kicked off, which can happen with high temperature, and which might ahppen at slow rate with time. There are probably failures where the ultra-accelerator breaks down and doesn't do its job.

Also, the point of sanding the surface of the tube isn't just to clean it, it's to provide a textured area, which gives the glued bond a lot more surface area, and makes it much stronger. Sand paper or emery cloth work much better than a cheese grater.

The layer of rubber that contacts the tube is a mixture of unvulcanized rubber and one of a few suitable vulcanization ultra-accelerators. There's an activator in the glue, which activates the ultra-accelerator. The patch then vulcanizes itself to the tube. Patches can fail from age if the vulcanization gets kicked off, which can happen with high temperature, and which might ahppen at slow rate with time. There are probably failures where the ultra-accelerator breaks down and doesn't do its job.

Does that activation imply that the glue needs to match the patch?? E.g. in Japan, patches and glue are marketed separately. For bigger tears you may e.g. buy a sheet out which you cut out a patch. Any shop will likely be offering a can of glue that can last for years without drying up. Myself I mix Rema and some quality Japanese products, but have yet to run into any problems.

I’ve had some problems (patch leaking in time) with the cheap patch kits I brought from a LBS. I have had good results form a plastic box patch kit I was given at the Bike to Work pit stop last May. These patches are smaller (like for a road bike tube). I don’t know if this is due to my patch skill level or the quality of the patch. However, I do notice a difference in the results: a good leak proof patch

Does that activation imply that the glue needs to match the patch?? E.g. in Japan, patches and glue are marketed separately. For bigger tears you may e.g. buy a sheet out which you cut out a patch. Any shop will likely be offering a can of glue that can last for years without drying up. Myself I mix Rema and some quality Japanese products, but have yet to run into any problems.

Well, there differences between glues and between patches, and the stuff from one maker is designed to work with their other products. But there isn't that much difference between them, and the chemistries are largely compatible. I don't worry about it excessively. At work, where I do most of my patching, I have an 8 fl oz (250 mls, roughly) jar of cement that came from an auto parts place, and which gets used with Rema and other patches with success.

...I to use to have no trouble patching tubes but now I have no confidence. For me I patch exactly following the directions. Maybe right away or several days later, I install the tube and begin to fill with air. At about 60 psi or so, the patch will let go.

Are your tubes perhaps stretching greatly to fill the inside of the inflated tire? This would tug at the edges of the patch, so can eventually lead to a creeping failure of the bond surface.

How about your sanding procedure? Are you getting it sanded down to a very dark flat black? Are you fully sanding down the seam lines?

The glue is best applied with a piece of plastic bag stretched over your finger. Also, the glue needs to be fairly fresh, and needs time to etch itself chemically into the rubber surface. The glue should thus be spread initially in a thick enough layer, slowly so it doesn't go dry quite so fast, and the glue spreading should stop before the surface tacks up.

Lastly, never breath on the glue, the glue attracts and absorbs moisture that can compromise the bond (this is much better known in the auto/truck tire repair world).
Always allow plenty of time for the glue to dry completely before applying the patch, or the patches may fall off.

And, I'll say it again, some tubes have a gummy texture and do not abrade cleanly, even after much continuous sanding. Such tubes aren't the best candidates for repair.

I have patched bike tubes for 40 years. Often I remove a flat and find a tube with 6 or even 7 patches that worked well until a new flat occurred.

Now however, I find patches are failing. Possibly this is due to a bad batch of patches, but I doubt it. I often find a patch that does NOT leak around the perimeter, instead it leaks right through the middle of the patch, as though the patch material is made of paper. I am not talking about the self adhesive plastic patches here, I am using the standard patches with glue etc.

Anyone else notice this? Or did I just get a few bad batches of patches?

Oh yes, I also notice that cyclometer quality has substantially gone downhill as well, but that's another post.

oldbluejeans
iambaughman.com

Unfortunately quality if steadily going downward, and especially since China has come into making products. Cyclocomputers are not what they use to be, I think Sigma is the only one left still making a half way decent product but their customer service sucks. I'm sure if you spend $350 for computer it should be of substantial quality, but for most cyclists who buy the under $100 computer it's a problem. But it's not just cyclocomputers it's a whole gambit of stuff being made. It use to be 40 years ago Consumer Reports reported that the average household major appliance had a life expectancy of 28 years, today they now say 12 years! You go out and spend $1200 for an appliance just to to replace it in 12 years, to me that's nuts. And the world screams about pollution yet we have to replace appliances every 12 years so we now have to manufacture twice as many products then we did 40 years ago which puts more of a burden on natural resources and waste. And small appliances are a joke, you could buy a toaster 40 years ago and it would probably still be good today, you buy a toaster today and you'll be praising your God that it made it through the warranty period. My espresso maker only lasted 14 months as an example. TV's 40 years ago were rated to last 20 years, today 8 years. It's all about keeping our money flowing out of our pockets and into theirs.

Sorry for the soap box spew. Like you, said: for another post. But it matters I noticed this too.

Anyway, I would buy new patches, sounds like you got a patch of bad ones, get the Rema's if glue on is the only type you want to use. If you want to try glueless get the Speciaized brand.

[QUOTE=dddd;14686727]Are your tubes perhaps stretching greatly to fill the inside of the inflated tire? This would tug at the edges of the patch, so can eventually lead to a creeping failure of the bond surface.

Thanks for your comments. The tire size is an odd 28x1.75 or 700x45c but the lbs sales the closest tube 700x35-44c. It works but when I need to patch, I wonder if the tube expanding to fill the 45c circumference stretches past the amount the patch stretches and boom. If so, the same could be happening to op.

I used to race on 700X45 sized tires, and often found myself looking for the very biggest 700c tubes I could find.

I think that now some of the 29er-sized 700c tubes would probably fill out the inside of a 45mm tire nicely without any wrinkling or buckling.
To campare the actual width of new 29er tubes, always measure the tube's width with the deflated tube folded flat, and you'll then know which brand is likely a better fit in a 700X45c tire.
A 44mm folded width should easily fit into a 700X45 tire, even knowing that most 45mm-labeled tires are not actually that big.

When it comes time to install the bigger tubes, have some air in the tube, but not to the point of stretching it. You can later release a bit of air as you are prying on the tire, if needed, but the air volume will help keep the tube free of wrinkles during fitment.
The additional advantage of larger-sized inner tubes is that punctures lose air much more slowly, since the hole isn't stretched open. You might even be able to ride home before fixing a small puncture.

Are your tubes perhaps stretching greatly to fill the inside of the inflated tire? This would tug at the edges of the patch, so can eventually lead to a creeping failure of the bond surface.

How about your sanding procedure? Are you getting it sanded down to a very dark flat black? Are you fully sanding down the seam lines?

The glue is best applied with a piece of plastic bag stretched over your finger. Also, the glue needs to be fairly fresh, and needs time to etch itself chemically into the rubber surface. The glue should thus be spread initially in a thick enough layer, slowly so it doesn't go dry quite so fast, and the glue spreading should stop before the surface tacks up.

Lastly, never breath on the glue, the glue attracts and absorbs moisture that can compromise the bond (this is much better known in the auto/truck tire repair world).
Always allow plenty of time for the glue to dry completely before applying the patch, or the patches may fall off.

And, I'll say it again, some tubes have a gummy texture and do not abrade cleanly, even after much continuous sanding. Such tubes aren't the best candidates for repair.

As I said before, stretching isn't a problem with a good quality patch because the patch isn't just adhered to the tube but actually part of the tube. Creeping of the bond isn't possible.

The glue should be applied directly from the tube and not manipulated after application. Just allow it to dry for as long as you can wait. You can't wait too long. Allowing the glue to dry overnight won't do any harm. Don't touch the patch with your fingers because it interferes with the bond. Water and water vapor shouldn't matter since the compounds aren't particularly water absorbent.

As mentioned, there are large variations in patch-kit quality, mainly with the composition of the patch and chemistry of the "glue". Do a test yourself by applying a patch, leave it on the bench for a couple days, then peel it off. The cheaper kits that use "rubber cement" mechanical bonding can be peeled off and the glue rolled off in little balls.

The higher quality kits, such as Rema and Camel use "vulcanizing fluid" that chemically bonds the two layers together with cross-links. There is no longer a separation or two layers; they are one. Trying to peel off the patch from these kits will result in tearing the patch and/or the tube in the process. The joint is just as strong as a single-layer of rubber.

After a couple of decades of doing these experiments, you get a feel for which patch-kits hold up better.

To deal with the stretching issue, I just pump up the tube to the same diameter it would be when it's inflated inside the tyre. Pour a drop of vulcanizing-fluid onto the centre of the patch and use that as a brush to smear the fluid over the hole and surrounding area. Wait 60-90 seconds to flash and press the patch onto the tube (pump it up again if it has shrunken during this time). I prefer this method because the 1st bits of glue are applied to the tube in less than a second from the last bits of glue. The drying time is the same. The painting-with-tip of glue-tube method many people employ takes too long and the 1st bits of glue are dried while the last bits applied is still too wet. Not to mention the uneven layer applied. And flakes of rubber inevitably finds its way into the glue tube and contaminates it. Causing the entire tube to be gone the next time you try to patch.

Some of you guys go through the weirdest antics just to put on a patch.

Just read this site: http://www.parktool.com/blog/repair-help/inner-tube-repairthe first section tells you how to use glueless patches, scan down to the second and it tells you how to do glue on patches. Both instructions say to use a alcohol pad to clean up the area on the tube after buffing, most of the time I don't bother unless my hands are really dirty. Notice the lack of weird ideas? no plastic bags, no gloves, no brushes, no stretching of the tube, no thick layers, and other blah blah ideas. Patching a tube is the simplest repair a person can do on a bike, it's not freaking rocket science.

I prefer this method because the 1st bits of glue are applied to the tube in less than a second from the last bits of glue. The drying time is the same. The painting-with-tip of glue-tube method many people employ takes too long and the 1st bits of glue are dried while the last bits applied is still too wet.

So you wait until the stuff you put on last is dried. Big stinkin' deal. It is impossible to wait too long for the glue to dry. If you can keep it clean and dry, you can wait weeks to stick the patch on. The purpose of the solvent in the glue is to carry the solids, which are what do the work. Spread a thin even layer, using something other than the patch, let dry, and patch.

As I said before, stretching isn't a problem with a good quality patch because the patch isn't just adhered to the tube but actually part of the tube. Creeping of the bond isn't possible.

The glue should be applied directly from the tube and not manipulated after application. Just allow it to dry for as long as you can wait. You can't wait too long. Allowing the glue to dry overnight won't do any harm. Don't touch the patch with your fingers because it interferes with the bond. Water and water vapor shouldn't matter since the compounds aren't particularly water absorbent.

Firstly, even using Rema patch kits exclusively, the bond strength varies a lot, a long cry from the patch being "part of the tube".
I see creeping patch failures often enough even after all the proper instructions were followed. Many tubes don't give such good adhesion.

The only "manipulation" of the glue is to spread it around, hopefully with the solvent having a bit of time to do it's thing before becoming almost dry (why thickened glue doesn't work as well, but works acceptably if spread on thickly at first, giving more time to "etch" into the tube surface).

The rubber compound isn't "particularly water absorbent", but the solvent is, and the bond can be compromised (why auto patching instructions specifically warn against this, and most patch kits say "allow to dry", not "you may accelerate drying by blowing on it".

Heh, I actually once observed the tire-repair guy blow on the glue before applying the patch inside my truck's tire. The kids they hire! Good thing that the air here is so incredibly dry.

Firstly, even using Rema patch kits exclusively, the bond strength varies a lot, a long cry from the patch being "part of the tube".
I see creeping patch failures often enough even after all the proper instructions were followed. Many tubes don't give such good adhesion.

I have tubes in my tires and in my box o' tubes that have as many as 30 patches on them. I patch around 100 per year and I've been riding bikes for 30 plus years. If creeping patches were a problem, I suspect that I'd have seen some by now. The only patches that I've had fail have failed because I rushed the job and didn't allow the solvent to evaporate or I contaminated the glue by touching it. The fact that the bond is instantaneous and permanent is sometimes a problem if you don't get the patch oriented properly.


The only "manipulation" of the glue is to spread it around, hopefully with the solvent having a bit of time to do it's thing before becoming almost dry (why thickened glue doesn't work as well, but works acceptably if spread on thickly at first, giving more time to "etch" into the tube surface).

By 'spreading it around' with a piece of plastic you are manipulating it. Put it on, let the solvent evaporate, and stick the patch to it. That's all it takes and the patch is permanently in place. If you try to remove it, you'll likely rip the tube rather than pull the patch off. I know because I've done exactly that.


The rubber compound isn't "particularly water absorbent", but the solvent is, and the bond can be compromised (why auto patching instructions specifically warn against this, and most patch kits say "allow to dry", not "you may accelerate drying by blowing on it".

The solvent used is xylene or toluene. Both are highly hydrophobic and do not mix well with water nor absorb water. Yes, the instructions say to allow it to dry but that is mostly an admonition against doing something silly like setting it on fire or breathing the vapors or trying to use an air nozzle to blow the solvent away (with the vulcanizing fluid). I don't blow on the vulcanizing agent myself because the solvent will evaporate quickly enough without extra help but blowing on it won't hurt anything.

Edit: The Rema document (http://http://www.rematiptop.com/technical/trm/technical_bulletins/RTTNA-003-TB-Effects-of-Artificial-Drying-of-the-Cement.pdf) on patching says not to blow on vulcanizing fluid with a heat gun because this will harden the surface and allow wet fluid to lurk under the surface. They also say to not use air from a compressor because the air is contaminated with oils which will interfere with the bond. I'd suspect that using polyethylene which is what most plastic films are made of could cause a similar problem.

Most agree that the solvent has changed over the years, but how do you know what it is?

Good to know about not using heat on the glue! I remember a guy who used a hair drier while patching piles of tubes at home.

WRT contamination from the surface of the plastic, any micro-layer of mold-release would not remain as a detrimental microscopic film, but would be miscible in the wet glue thus preventing it from having any significant effect on bond strength. Solvent-based glues are very good at dispersing any contamination "film" as long as the glue is agitated on the surface, and in any case the plastic wrap is not left between the tube and the patch. The plastic protects your finger while preventing skin detritus, moisture and oils from contaminating the glue.

You have to spread the glue around, else the glue would be dripping off the tube and the drying time would be enormous. Most patchers have noticed this I'm sure, that an even layer dries fastest.

Most tubes take well to patches and things become not so critical except for allowing the glue to dry, using fresh glue and not touching the patch. I typically use just a quarter of a patch for typical thorn punctures with lifetime reliability, but I do test the first patch that I put on any tube.

Its the glue its the glue its the glue.... Rema has about the best cold vulcanizing glue (so does Tractor Supplys Cats Paw or Monkey) but once you open the tube its all over... This is in-part a problem imposed by EPA regulations of Toluene... Because of high temperatures 90-100+ this is how I do it in Texas...

I buy cheap $1.50 patch kits knowing that once I open the glue its no good in two weeks - I keep an unopened patch kit in my bag for road use - After roughing out the surface I now clean the tube of with alcohol swabs or even patch glue then I put the glue on the tube and also the patch and let them sit till I can't stand it anymore - After a patch is put on I will wait a week before pumping up - If I have to use the tube immediately then I pump it up once in the tire and not before - Hope this helps...

PVC Cement for pipes works about three months, Superglue works about 5 days, Rubber cement 4 hours, Reagent grade Toluene after a Cyclohexane wash melts the two together leaving a weak spot on the tube, 3M Yellow Vinyl Gasket adhesive works permanently but turns hard...

The 3M glue needs further testing - I think that the 3M glue might just work all by itself???

Most agree that the solvent has changed over the years, but how do you know what it is?

The solvent hasn't changed since I've been using it. As a chemist, I know what the various aromatics smell like. Toluene and xylene have a very characteristic odor.


WRT contamination from the surface of the plastic, any micro-layer of mold-release would not remain as a detrimental microscopic film, but would be miscible in the wet glue thus preventing it from having any significant effect on bond strength. Solvent-based glues are very good at dispersing any contamination "film" as long as the glue is agitated on the surface, and in any case the plastic wrap is not left between the tube and the patch. The plastic protects your finger while preventing skin detritus, moisture and oils from contaminating the glue.

It's not any release compound...there probably isn't any...that causes the problem but the plastic itself. The plastic is soluble in the solvents and could interfere with the bond. It's also an unnecessary step because the solvent will evaporate by itself.



You have to spread the glue around, else the glue would be dripping off the tube and the drying time would be enormous. Most patchers have noticed this I'm sure, that an even layer dries fastest.

How much are you using? If you are putting on enough that it's dripping off, you are putting on way, way, way too much. A 2 oz tube should be enough for many...10 at least...patches. Yes, you need an even layer but you need a thin even layer.

I've had issues before with the air pressure blowing a hole right through the middle of the patch where the original hole was. I believe it's something to do with the chalk dust (or whatever it is) inside the tube blowing onto the outer surface of the tube just as I put the patch on, thus creating an unstuck cavity which the pressure can stretch out. I've found that using a slightly wider tube helps as it has to stretch less before it fills the inside of the tyre.

The best patches I've used are those made from an old tube as these are slightly thicker. However these need more careful preparation before use. This can be done at home though, and the prepped patches then taken on the bike.

I've had issues before with the air pressure blowing a hole right through the middle of the patch where the original hole was. I believe it's something to do with the chalk dust (or whatever it is) inside the tube blowing onto the outer surface of the tube just as I put the patch on, thus creating an unstuck cavity which the pressure can stretch out. I've found that using a slightly wider tube helps as it has to stretch less before it fills the inside of the tyre.

The best patches I've used are those made from an old tube as these are slightly thicker. However these need more careful preparation before use. This can be done at home though, and the prepped patches then taken on the bike.

I used to be a tire service guy. I've fixed tubes on everything with tube type tires, from lawn mowers to excavators. that includes some things with monstrously huge wheels, which have tubes that cost $500. And which no one stocks, because they cost $500. You can do things like cut the valve stem off, patch the two inch diameter hole you just made, cut another hole, and glue a new valve stem in place. If your patches blow off, they're too small.

Tubes make horrible patches. For one thing, they're excessively thick, and more importantly, they do not have the specially prepared layer of unvulcanized rubber that a proper patch does, that's very important in the cross linking.

I'm just going by experience here. The problem I had was not necessarily the whole patch blowing off, but the air pressure blowing a hole through the middle, leaving the edges secure. Might have been a bad batch of patches. I've never had a recycled tube patch fail if properly prepped. The feathered-edge patches are without doubt easier to use though.

Inner tubes are used as patches extensively around the world, but there are issues.

Pete mentioned getting best results using a tube that doesn't have to stretch too much to fill the tire, and I believe this is doubly important when an elastic patch material is used.

As I explained a while back, if the patch stretches, and the bond isn't fierce, the tube itself starts to pull away from the patch as a flat, planar surface, starting at the original puncture hole. This was the failing of the original "Speed Patch" product, which was made from what apparently was a very thin microcell (closed-cell foam) rubber sheet. These patches failed reliably within a day, always starting at the hole. By the time the post-mortem occurred, you could see the circle where the talc had contaminated the adhesive until the circle reached the edge of the patch (at which point the air speedily escaped).

I really test the limits sometimes with my quartered patches, which have only one of three edges "feathered". These are less tolerant of every patching variable it seems, yet can be lifetime-reliable if the tube-sizing and bonding issues are considered. We have goat-head thorn infestation here, so the tiny holes are prime candidates for micro-repair and you can get about 25 repairs out of a single Rema-type patch kit.

I know people who use glue on patches and I haven't heard of one case of "the creeping patch". If the patch is creeping it's because something in the act of preparing the tube to accept the patch has failed. No it and's or but's. Rema patches are designed to stretch a tiny bit, this stretching thing has gotten way out of line. I've pumped up tubes outside the tire with a Rema patch on to the point where the tube was about 2 times larger then the tire, and the patch stretched just enough to keep from tearing but the tube did have that sucked in gut look where the patch was but the patch held with no problems. Don't take my word for it, try it yourself, take one of your patched tubes and just blow it up to 2 times larger then the tire it went into, and if that don't satisfy you pump it some more to 3 times larger and see what happens. I've even done that with glueless patches and the glueless patch never failed either.

I'm with Cyclocommute on this, I helped a stranded cyclist about a month or two ago fix his flat, he had Rema glue on patches, it smelled and felt the same as it did when I used the stuff over 18 years ago. And guess what? It stuck the same too. And a lot of people put too much glue on, it just has to be a very thin coating, and the tube surface needs to be roughed up like the Park web site says that I gave everyone so they could read it and learn...of course nobody learned a damn thing from it because we're still talking about creeping patches, the glue has changed, the patch won't stretch, you can tear the patch off, blah blah blah.

Today's electronic generation had lost touch with mechanical abilities we once all had.

This is my week to be a jackass, hopefully sometime by the end of the week I will go back to being politically correct again.

For the poster with the patch blowing a hole through the center, is this happening AFTER you re-install the tube and then you pump air then it's flat again, or is it happening before you put the tube in the tire? Regardless I would throw those patches away and get Rema, their quality has always been very good. Personally I like Specialized glueless patches, but the electronic generation can't seem to figure out how to make them work.

Well, I wouldn't make any generalizations about which generation is doing what. The rema patches are designed not to stretch, what you're seeing is the elastic feathered edge region stretching and that's it.

If the patch and tube stretches, as I said, you'll need a perfect bond or else. And not all tubes will give you that perfect bond even if you sand nearly through the rubber and put your best thin film on there. The Rema cement clearly is mostly solvent, so no problem with getting a thin film on there unless you deliberately just sat there pouring the glue and going on and on with a circular motion. No one here does it that way, electronic generation or not.

As for the patches getting a hole in them, I've seen this, to much surprise!
After all, with the tire's casing behind it, there's nothing but compressive force on the patch!
It is a materials problem with recent patch kits sold at large department stores like K-mart. I bought these once, in an on-the-road emergency, and will not buy square patches again because of this. The patch simply grows a bunch of cracks in the center of the patch!

Ok, lastly, on the glueless patches. I had a flat at the coffee shop last month. I still had a further mile to ride home after our 30 mile ride, so out came the glueless kit at the coffe shop table outside.
Plenty of time to do it right! We kill almost an hour over coffee!
I sanded that tube with the greatest of care. A seam was buffed down to nothing and the entire area was the perfect charcoal-black shade of fresh-cut butyl.
The repair went well using a Park patch, and I rode the bike home.
The next day, based on my years of experience, I pulled the tube out to inspect the patch.
Despite the greatest of care applying the patch, really pushing hard on it to improve the bond, the patch is failing.
There are air voids starting at the corners, working past the half-way point towards the hole, where an area of separation also exists.
The patch didn't fail, but would have. The Park patch did it's job as a temporary repair, and might have lasted years in a smaller tire that didn't allow the tube to stretch so much.

I know exactly what ya'll saying about a Rema patch being "better than it needs to be".

But there are variables beyond patching procedure that can still let you down. I use and trust Rema, but not so much trust in the tubes, since I've had these patches almost fall off during the tube installation.
And I disagree that there ever was a time when "mechanical abilities that we all had" would do anything to prevent it. I even know how to read!

Yes, there hasn't been a glueless patch yet that can rival a vulcanized patch. These are only meant to be emergency on-the-road repairs to get you home. Then you peel off the patch and apply the proper repair: a regular patch with vulcanizing fluid.

As for blowing a hole through the patch. The only way you can blow a hole through a patch is if you re-install it inside the tyre with the same orientation so that the patch is under the original hole in the tyre. In which case, there isn't a strong casing around the outside of the patch for it to push against. The pressure inside the tube is 6-8x higher than the outside air and it'll push right through.

This would've happened just the same if you had replaced with brand-new tube. A new tube actually has a thinner rubber layer underneath that hole in the tyre than a patched tube. And the air-pressure would blow a hole through the tube out the hole in the tyre just the same.

Well, I wouldn't make any generalizations about which generation is doing what. The rema patches are designed not to stretch, what you're seeing is the elastic feathered edge region stretching and that's it.


The patches may not stretch as much as the tube but they do stretch enough. Blow up a tube with a properly installed patch on it to 2 or 3 times its flat size and watch what happens. In the tire, the tube doesn't have to stretch nearly that big so it really isn't a problem.

I think some of your problems may lie in the false economy of cutting your patches up. A patch kit is cheap. A box of 100 Rema patches is around $14 which is dirt cheap. You can even get small size ones...the F0...which work nicely for goatheads.

Yes, there hasn't been a glueless patch yet that can rival a vulcanized patch. These are only meant to be emergency on-the-road repairs to get you home. Then you peel off the patch and apply the proper repair: a regular patch with vulcanizing fluid.

.

This is pure BS!! I mentioned this already a thousand times as well as others and still the BS persists. I've used tubes as my main tubes for up to 5 years with as many as 13 glueless patches and not one has ever failed. I've been using nothing but glueless patches for about 18 years on both my spare tubes and my main tubes and never had one fail. It is not mean't to be an emergency on the road get me home so I can do a proper job. Why would anyone use such a patch and waste that much time! Think about, your going to use a glueless patch on the side of the road then go home take the damn tube back out peel the patch off and put on a glue on type...that's insanity! When all you have to do is patch the damn tube with a glue on tube to begin with. The reason glueless patches sell for is because they work!! I don't know one person who would buy a glueless patch to use only to go home and redo the job, if that were true manufactures of glueless patches would have stopped making them years ago due to very low sales. Anyone with half a brain wouldn't want to patch the same hole twice.

Peel off the patch huh? Tell you what, you use a glueless patch and leave it on for the season inside your tire and then try to peel it off and tell me what happens. I'll tell right now what will happen, you'll take a chunk of the tube with the patch! And in that season you're waiting you'll discover the darn patch worked and it didn't leak, the next thing you know you're using them instead of the glue on patches.

There are some bad glueless patches, most of those are found at Walmart, but the good ones are made by Specialized and Park, go outside those brands and I can't vouch for them.

This was the patch from the other day, Park brand.

Note that the other 3 corners had the same creeping failure, but I pressed on the patch which appears to have re-bonded those failed areas.
Notice also that the tube was buffed fully to flat black, down to the rubber, and that the freshly-peeled patch was repeatedly pressed on with real pressure.

The failures all started at the corners and worked towards the hole, which was not as big of a hole as appears here. A complete failure with air loss did not yet occur, yet from past experience I decided to have a look.
Tugging at one of the corners that I pressed back down shows that a re-bonding has occurred, yet the adhesion doesn't hold up to being inflated in the tire for a few hours.

Note also that this tube measures 26mm wide in a flattened state, fitted into a tire that was nearly, but not quite 27mm inflated width. This is a very normal, middle-of-the-road width ratio for high-performance road bike tubes/tires.

But this is all BS, I'm from the stupid generation, I wiped my forehead with the sticky side of the patch, blah, blah, blah.


http://farm9.staticflickr.com/8038/7947936070_6a36372d2b_z.jpg

Maybe this is a dumb question, but when you put glue on the tube, presumably you want to use a little too much, to ensure that all of the patch is sitting on glue. This means there will be a little glue on the tube around the edges of the patch. What is the risk of that circumferential glue causing the tube to bond with the inside of the tire, so that you can never get the tube out again (without ripping it)?

I've never had this happen, but I don't understand why not. Do they make the inside of tires so they are not chemically compatible with patch-glue?

Anyone ever use Slime Patch Kits? The patches have a cellophane cover over the non glue side that is suppose to be left on. This keeps your fingers out of the glue and keeps the glue from sticking the tube to the tire. Can't say much for the Slime patch kits a I've had nothin but bad luck with them. They are the only ones sold by lbs, and Walmart here.

Maybe this is a dumb question, but when you put glue on the tube, presumably you want to use a little too much, to ensure that all of the patch is sitting on glue. This means there will be a little glue on the tube around the edges of the patch. What is the risk of that circumferential glue causing the tube to bond with the inside of the tire, so that you can never get the tube out again (without ripping it)?

I've never had this happen, but I don't understand why not. Do they make the inside of tires so they are not chemically compatible with patch-glue?

It's possible. It doesn't happen too much, because the tire isnt' usually prepared for patching, and so it's not likely to stick. Also, remember that the patch is part of the system: it's got ZDDP or similar in it, which is a vulcanizing ultra-accelerator. the vulcanizing accelerator in the cement is there mostly to kick it off, and allow the reaction to work at room temperature.
If you're worried about it, it's pretty easy to rub off the excess glue once you've put the patch on.


Patches sticking to the tire carcass is a real problem in truck and auto tube type tires, where there is much more heat available to vulcanize the tube to the tire: a plain tube with no glue can get vulcanized to the tire. The usual solution is talc or chalk, which keeps the tube from sticking to the tire.

For reference, I've noticed that the inside surface of bicycle tires is generally quite bond-resistant, prep or no prep.

I've long wondered how to make a Rema patch boot repair stay in place more reliably. Must be a different kind of rubber, that and the casing fabric itself of course won't vulcanize.

If a Velox-tape repair stays put during a routine, subsequent patching repair, I consider that fortunate.
The Velox tape really does make a durable patch for the tire itself, and I have gotten full mileage from the booted tires.

Yes, however I think the patches failed due to very high heat...120* unglued em like throwing cold water on to stuck dogs.

This was the patch from the other day, Park brand.

Note that the other 3 corners had the same creeping failure, but I pressed on the patch which appears to have re-bonded those failed areas.
Notice also that the tube was buffed fully to flat black, down to the rubber, and that the freshly-peeled patch was repeatedly pressed on with real pressure.

The failures all started at the corners and worked towards the hole, which was not as big of a hole as appears here. A complete failure with air loss did not yet occur, yet from past experience I decided to have a look.
Tugging at one of the corners that I pressed back down shows that a re-bonding has occurred, yet the adhesion doesn't hold up to being inflated in the tire for a few hours.

Note also that this tube measures 26mm wide in a flattened state, fitted into a tire that was nearly, but not quite 27mm inflated width. This is a very normal, middle-of-the-road width ratio for high-performance road bike tubes/tires.

But this is all BS, I'm from the stupid generation, I wiped my forehead with the sticky side of the patch, blah, blah, blah.


http://farm9.staticflickr.com/8038/7947936070_6a36372d2b_z.jpg

It looks to me like the plastic backing on the patch is coming off. There's nothing wrong with the patch. With the exception of some very old and very weird urethane patches, all the patches I have every seen are made of black rubber not clear plastic.

Maybe this is a dumb question, but when you put glue on the tube, presumably you want to use a little too much, to ensure that all of the patch is sitting on glue. This means there will be a little glue on the tube around the edges of the patch. What is the risk of that circumferential glue causing the tube to bond with the inside of the tire, so that you can never get the tube out again (without ripping it)?

I've never had this happen, but I don't understand why not. Do they make the inside of tires so they are not chemically compatible with patch-glue?

It won't bond all that well but it may stick to the tire. That's the main reason I use talc in my tires.

Yes, however I think the patches failed due to very high heat...120* unglued em like throwing cold water on to stuck dogs.

You might have that problem on cheap patches using rubber cement. Rema's don't use 'rubber cement'. They use a vulcanizing fluid that is part of the patch/fluid/tube system.

Maybe this is a dumb question, but when you put glue on the tube, presumably you want to use a little too much, to ensure that all of the patch is sitting on glue. This means there will be a little glue on the tube around the edges of the patch. What is the risk of that circumferential glue causing the tube to bond with the inside of the tire, so that you can never get the tube out again (without ripping it)?

I've never had this happen, but I don't understand why not. Do they make the inside of tires so they are not chemically compatible with patch-glue?

No, you use just enough to put a thin coat evenly over an area slightly larger then the patch will cover, too much glue and it interferes with with the bonding. And by spreading it on slightly larger then the patch you don't have to worry about the edges of the patch not sticking. And due to the rough surface of the inside of the tire and the material it's made of the tube will never bond to the tire.