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.

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.


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 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.

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.

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/8038/7...36372d2b_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.

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.

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.

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.

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.

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.

This is correct. There are certain brands of patches you should use and avoid the other brands to be safe. Rema is the best glue on patches and glue available and have been for more then 40 years since I've been riding; and Specialized and Park have the best glueless patches available. Use any other brand of glue or glueless stuff and you're asking for problems.

I can tell by looking at the patch you did it wrong!! If you notice the darker center area, that area you pressed on hard for about 30 seconds, but you didn't do that to the corners and edges properly so you got the frosty look because you didn't press it there. This is entirely a preparation failure. When I'm done with my patching they never look like that, they look black across the entire patch.

I agree that you only need a thin coat of vulcanizing fluid, however a thick coat just requires a much longer drying time. It will still bond if it is totally dry but getting to that point may take a very long time. If you have the glue dripping down the sides of the tube, you've put on enough glue for a box of 100 TipTop patches;)

There's another reason that the TipTop patches won't bond to the inside of the tire. The Rema system is a 2 part system. The vulcanizing fluid contains one part of the bonding agent and the patch is coated with another part. Once in contact, the patch and the vulcanizing fluid start the process of grafting new rubber bonds onto the tube. The tire doesn't contain the part of the system that the patch does and, thus, won't form the same molecular bonding. The vulcanizing fluid may 'stick' to the inside of the tire but it's a weak bond.

Great scientific stuff explained in simple terms so we can understand it, thanks Cyccommute!!

Probably why I saw people who used too much glue for a patch have a failed patch was probably due to them not waiting long enough for the glue to dry rather then interfering with the bonding process like I said, but maybe that's the same thing, but regardless, you explained it very well so we could understand it. You have been very knowledgeable and helpful on this subject. Two thumbs up!!

Is there a risk of letting the glue dry too much (I am talking hours, not months)?

No problem, as long as the glue surface doesn't get contaminated by anything like dust. Remember, certain dust particles are attracted to certain materials by static charge or polar attraction.

I usually begin the drying by whirling the glued tube above my head, which shows rapid initial drying.
But, there are thicker spots where the solvent can take at least several minutes to even APPEAR dry, so a good long(er) drying has it's merits.
There is also the matter of the amount of solvent which permeates the tube rubber to the point of apparent swelling, but the visible symptoms of this appear to decrease within several minutes. The solvent is indeed quite volatile. Thinner tubes show a greater, more rapid dimensional change from the absorbed solvent, but appear to normalize within 5-10 minutes.