That's what you get for thinking...
 

For some reason I always assumed that if a leak was coming from a patch the tube was trash because you can not patch over a patch.

I haven't had this happen a lot, but it has happened and happened again today, however, since I found a patch kit I didn't know I had I figured I'd try and patch over a patch. Not only did it work, but I think it's my best patch job and it looks kind of neat with a patch over a patch.

BTW, this was not a puncture through a patch, it was air leaking from the edge of the patch, near a section that was peeling away. I simply cut away the loose patch material (very small amount) with nail clippers, then sanded, applied glue and patch as normal.

Hey, I assume you didn't completely cover the first patch with the second patch, but just patched over the edge of the first patch (with the second patch). I've never tried that before (I've never tried patch completely over another patch either). I guess I would have tried to completely remove the first patch and start again dealing with the original punture. That might not have been easy to do if the old patch (the part still attached to the tube) was really bonded to the tire. Anyway just goes to show that it's worth trying an idea out to see if it will work.

First off, you're using the good patches with vulcanizing fluid, like Rema, right?

Make sure you rough up the tube and let the glue completely dry before applying the patch for the best bond. Also, if you remove the clear plastic, fold the patch a couple times to make the plastic tear then remove it from the inside rather than risking pulling up the edges of the patch.

I've had to rip off and re-do a leaky patch before, mainly because I didn't follow my own tips above.

I've been using Elmer's rubber cement. Maybe it's not supposed to work, but it works. I got a bottle in the stationery aisle at my drug store. It's cheap, too.

That's correct, I did not cover the entire patch, only about 1/2 of it. I've tried to remove a patch before and it's just too difficult and figured it was not worth the effort. I've done many, many patch jobs and got many tubes with tons of patches, because I like to keep a tube as long as possible, but I draw the line at removing patches, I'll buy an new tube first:D

That's interesting. I've been wondering if there was a glue I could buy, becaus I usually have a surplus in patches, but run out of glue. Do you use the Elmer's glue in the same way as the traditional glue?

BTW, I've used the glueless patches before and have not had any luck with them, so now only use traditional glue-on patches. Anyone else have a similar negative experience with the glueless patches?

I carry them as an adjunct to a spare tube and use them if needed to patch on the road. I find they'll usually work fine for a few weeks but will eventually start leaking, so when convenient, I either replace the tube or pull it and put a "real" patch on.

Glueless patches haven't worked for me. What a scam.

John, I brush the glue on, spread it around, wait for it to dry, and apply the patch. In other words, I use it just as I use expensive glue. And they definitely hold.

I believe the primary purpose of the glue is to hold the patch in place, not form an airtight seal. The rubber makes the seal. Air pressure keeps the patch from moving. The patches I place with Elmers look every bit as good as the others. Every bit.

Having used and smelled both the glue provided in patch kits and the classic rubber cement I'm pretty sure they are the same thing. The secret seems to be keeping the big jar of rubber cement from drying and turning thick. Some rubber cement thinner bought at the same time and used to keep it thinned to the best consistency seems like a good idea.

I almost never patch on the road. I carry atleast two tubes and just replace the tube and then patch the leaking one when I get home.

Well, I'll be going to the store and see if I can't find me some Elmers.

Let us know what you think!

Glueless patches are temporary use only , mainly to get home with. Lot of people make the mistake by putting air in the tube before putting it back into the tire, which pull the patch to far and doesn't hold.

I read the instructions and don't remember anything about not inflating prior to installing, but I could be wrong. Regardless, if they're only temporary patches, as you say (I also did not know that), then I'm definitely not interested.

The instructions with most glueless patches don't tell you this and that why people makes the mistake . It up to the shop people to tell you this when you buy them and most don't because they don't know or they forget to. Glad to be a help to you.

I also use a jar of Elmer's rubber cement. For patched I cut a square of rubber from an old tube. Works great.

That's crazy! What responsible company would omit a very important part of the instructions, only to rely on the merchant to inform the customer.

Agreed. Maybe they consider it common knowledge, making it redundant to print it in the package. I disagree with that.

Ratzinger, I don't use squares of inner tube because with small inner tubes, the feathered edge can help adhesion and prevent bulges through the tire. I would use "square edged" patches on wide tubes. That's all we could get when I was a kid, anyway.

Well, I bought a 4oz bottle of Elmer's Rubber Cement and it so far works. I also have some DAP Weldwood contact cement http://www.dap.com/product_details.aspx?product_id=47 Just curious if anyone used this as well, in lieu of glue that comes in patch kits?

I had an experience yesterday to add to this "huh, that actually worked to fix a flat" thread. To preface I've been lax on keeping my supplies and equipment up to par (for example, my floor pump leaks air while I'm pumping, so I have to pump fast and get it disconnected fast, and my front tire is really starting to look rough and I've got it booted with newspaper that I got from the side of the road when I did a road-side flat-fix).

Yesterdays ride was approximately 6 miles out, turn around, and 6 miles back. I have often in-the-past carried an extra innner-tube but one wasn't handy (like I said I need to get myself together and be better prepared) and I knew the farthest I would have to walk is 6 miles and I had plenty of time and I figured I'd risk it (maybe I'm lacking excitement in my life and wanted to live "dangerously").

I had fixed a flat on-the-road a few weeks ago and at that time my glue was barely liquid, but it worked okay. Yesterday my flat happened about a mile and a half from home (on my way back). I thought about walking the last bit but I figured why not try to fix the flat and avoid the "walk-of-shame." This time what little glue was left in the tube (I rolled the tube like a tube of tooth past and I tore the tube apart to get access to what was left) was closer to a solid than a liquid, it rolled in my fingers like play-doh. I roughed-up the area around the tube-hole with my metal "sander" thingamagig and put a BB-size glue ball over the hole and put the patch on. I tested the patch a bit, it easily peeled back off, and the former glue-ball (now flat) pretty much stayed together (meaning it didn't really look like it was "trying" to bond to either the tube or the patch to any significant degree). It did stick enough to keep the patch in place and that was it. I really had no confidence in this "fix". I was able to pull some more glue out of the very end (from the area behind where the top screws on). I pried the glue out leaving shiny metal behind (like I said this glue was more solid than liquid). I mixed this glue ball with my original, which I easily able to retrieve from my original attempt at fixing the flat (there was a tiny bit of glue that "tried" to stay behind on the patch when I retrieved the original glue-ball). I ended up with a pea-size glue ball, I put it over the tube-hole and put the patch on top, I squeezed the patch onto the tube until "glue-doh" was showing coming out under the patch on all sides. I got the tube back into the tire just hoping that the patch would not be knocked off in the process. I got maybe 30-40 PSI in it (my frame pump is actually still working well) and it held and I slowly made my way home.

This make me think maybe even chewed chewing gum would work in a pinch (before yesterday I would have bet on the chewing gum over what I was using)

This glue came out of an "official" (though X-mart/cheap) bike patch-kit, but it looks very "generic," it reads "RUBBER CEMENT, FOR ALL RUBBER REPAIRS, the fine print on back read that it contains heptane and toluene which are apparently flammable and/or poisonous according to several warning sentences. The tube also reads Bell automotive products, inc.

I found similar looking tubes of glue for sale in the automotive section at Walmart last night. I bought a "Slime" (car) tire plug kit which contained a .41 OZ. tube that reads "RUBBER CEMENT" and contains heptane and petroleum distillate (the whole kit was $3.00). Unfortunately the tube in the kit has a hole in it and I will return the kit for another one. I am going to use the small tube in my bike repair kit and have the car-kit on hand to repair possible holes in my car tires, which I've never tried to do before, but have had done by a mechanic a couple of times in the past year. There was also the same glue being sold alone (not in a kit) in a tube about three times bigger (I'm guessing 1.5 OZ.) for around $1.88. I usually run out of glue before patches so this is good to know.