Originally Posted by HillRider

OK, finally a reasonable chemistry based explanation of what is being sold as "vulcanizing fluid" and how it really does cross link the bond between the tube and the patch. Thanks for the reference and it's nice to know it's not all marketing puffery and snake oil.

That said, plain, cheap Elmers Rubber Cement used with REMA patches has worked for me with complete success for patching tubes for many years. It may not be the best system from a chemistry or theoretical standpoint but it does work. Now, I don't routinely bomb down Alpine passes and heat my rims red hot but for the normal hilly conditions around me the patched tubes have been 100% reliable.

Originally Posted by chucky

With all the things that could go wrong with tube patching from not having a suitably sized patch, to insufficient scraping of the area (or having tubes made with contaminated rubber), to dirt/talc fouling up the chemical reaction, to having the tube accidentally bond to the tire (or tire liner), to the glue drying up (or possibly being the wrong type, even if the label says it's for tire patching), to the patch just randomly failing, to the time wasted...it's just not worth it except for emergencies (especially when the magic Rema patches and "vulcanizing fluid" that some claim are needed to make the voodoo work cost nearly as much, per repair, as a brand new inner tube).

Originally Posted by DannoXYZ

I've gone through brand-new brake-pads down to the metal posts on a single downhill.

Originally Posted by dman-ebike

I was tired of cutting up the bigger patches and grinding them with a dremel to make them smaller for the road type tubes.

Originally Posted by DannoXYZ

Quick glance through ingredients shows:

Elmer's No-Wrinkle Rubber Cement
>70% Heptane
20-25% natural latex rubber
1-5% Isopropol alcohol

Rema Vulcanizing Fluid
60-95% Naphtha, petroleum, hydrotreated light
1-2.5% N-Ethylcyclohexylamine
other brands also contains: acetone, heptane, trichlorethylene, zinc-dibutyl dithiocarbamate/dibutylamine

Now we can see that the office-stationary "rubber cement" is clearly of different composition than "vulcanizing fluid" regardless of how it's labeled. Leave a bottle of rubber-cement open and you end up with a ball of rubber about 25% the size of the container. Leave a bottle of vulcanizing fluid open and it evaporates to nothing; very different stuff. The N-Ethylcyclohexylamine is a vulcanizing accelerator/catalyst which speeds up vulcanizing enough to occur at room-temperature (heat does the same thing). Ever see "RTV" on various rubber-sealants like caulk? The red uncured rubber on the patches provides the sulfur and in the old days with skinwall tyres, you can see a brown circle appearing on your tyre if you install the patched tube right away. This is caused by the release of various gases during the curing process.

A lot has changed in the past 20-30 years. Just because there was only one way to vulcanize rubber 30-years ago, doesn't mean that technology hasn't improved. Look at how materials technology has improved in frame materials, and how mechanical engineering designs created index shifting. Auto and computer technology has improved significantly in the past 30-years.

In the end, it's not an all-or-nothing, black & white, yes/no issue on patches. It comes down to a shades-of-grey on how well various compounds holds a patch to a tube. I'll do a demo video of "rubber cement" versus "vulcanizing fluid" after 24-hrs curing and show how easy or difficult it is to pull off a patch using both these products.

Originally Posted by Rapido

Maybe the inner tube rubber compound was modified to discourage using patches





Up in time until the mid (?) 80's I could permanently patch any bike inner tube along side the road in about five minutes. Then, later, the patches no longer would stick to the newer inner tubes. I suspect the inner tube manufacturers did something to the tube's chemical compound to discourage tube repair common attempts. Some of my tubes would have as many as 12 permanent patches. Of course that was a lot less expensive than forced to buy 12 new tubes. In those days I never imagined I needed to carry spare tubes. But of course I'd have two tubies bandoleered on my torso when I used sew-ups all of the time.

Originally Posted by chucky

Oh BTW Farm & Fleet has patch kits for $0.69 a piece (plus shipping):
Monkey Grip EZ Fix Bicycle Patch Kit at Blain's Farm & Fleet

Originally Posted by KD5NRH

Which revives the question I had while looking at the kits in a local farm store the other day; WTF is that big one for? The one in the store was 3x5", and I don't care how far I am from home, I'm not trusting any tire that has a patch that big on it.

Originally Posted by kevindsingleton

There's your trouble: don't patch the tire; patch the tube!

Originally Posted by KD5NRH

Which revives the question I had while looking at the kits in a local farm store the other day; WTF is that big one for? The one in the store was 3x5", and I don't care how far I am from home, I'm not trusting any tire that has a patch that big on it.

Originally Posted by Studly

Just to update an old thread, I found a good deal on a large 1 oz tube of Slime rubber cement (made just for tire/patch/rubber repairs) for about $2 at my local Walmart, in the auto dept. If you read the reviews of Slime rubber cement in various sizes on Amazon, you'll see it's highly rated and used by a lot of people for bike tube patches. If you need a bigger size, I found an 8 oz. can of the same product for about $6 in the auto section of my local Fleet Farm (a Midwest chain), but I'm sure you can find the same thing at auto stores.

For those of you who use the 100 packs of Chinese patches, what has your experience been like? The reviews vary greatly for this product. Some say they work as good as the Rema patches at a fraction of the cost. Many others say the patches aren't pliable enough, are too large for road bikes (although I assume you can cut them down) and the backing comes off too easily so they get dried out too soon and don't have a long shelf life. However, these problems could be related to if they bought the patches from a bad vendor, who had old stock and, as a result, the patches became dried out and less pliable before the person even received them.

So for those of you who buy these 100 pack of patches (looks like you can also buy a 100 or 48 pack of the same ones for cheap on ebay), were they pliable enough to use and did the patches last once applied? If so, do you remember what vendor you bought them from? Also, what is the shelf life of these patches if you store them in a sealed bag?

Originally Posted by D1andonlyDman

I've had good luck with the cheap patches from China on ebay, and vulcanizing fluid bought at an auto parts store. A 1 ounce tube is about $2.50, a 4 ounce can is about $5. I've not had any experience of the patches going stale, but I've only had them for maybe 18 months. Make sure you get the ones with the orange rubber backing that is the same as the Rema patches.

Originally Posted by Studly

Thanks for the feedback and tips! I see two main types with the orange backing on Ebay: one is round, 25mm; and the other is rectangular with rounded corners, 33mm x 23mm.

Which do you have and recommend: round or rectangular?

Also, I did see this interesting note from a top-selling listing on ebay for the rectangular patches: "NOTE: We did find fake RED SUN tire patches with lower quality in the market. You can easily pick out the bad ones with eyes. The fake patches look dry and hard. The patches we sell are from original manufacturer. It looks soft and comfortable."

Maybe that's why some people in the Amazon reviews had such bad luck with their non-pliable patches: they bought from a vendor who sent them fake/inferior ones, while others send the name brand (Red Sun?) ones?

Originally Posted by AnkleWork

Considering the low economic utility of a tube that reliably holds air, and the value of your time and effort, you should always use the absolute cheapest patching materials -- free if possible.