Bicycle Mechanics - adventures in thorn resistant tube repair - how to create a patch?

i've come to the conclusion that normal patches simply don't work on thorn resistant tubes. i don't know why. i've perfected my patching technique.

now i'm trying to see if its easy enough to create a patch. i cut up another thorn resistant tube, sanded the inside (where it will contact the tube), wiped the patch and tube with acetone to clean, applied rubber cement, waited for it to dry, pressed the patch on the tube AND

nothing, no stick.

anyone know how to create your own patch?

Did you apply rubber cement to both the tube and the patch?

If you are using rubber-cement instead of vulcanizing fluid, that's a problem right there. Did you sand and clean up the area on the tube where the patch is to be applied as well?

Also don't use acetone to clean, it will interfere with the vulcanizing fluid. Just sand both surfaces well to remove the mould-release compound and blow off the dust. Apply a drop of vulcanizing fluid to the centre of the patch and press onto the tube. Wiggle it around to spread out the fluid evenly. Pull off and wait 20-30 seconds to dry and get tacky. Press patch on and hold for 20-30 seconds.

Only applied it to the tire and not the patch. I'll give that a try.

If you are using rubber-cement instead of vulcanizing fluid, that's a problem right there. Did you sand and clean up the area on the tube where the patch is to be applied as well?

Also don't use acetone to clean, it will interfere with the vulcanizing fluid. Just sand both surfaces well to remove the mould-release compound and blow off the dust. Apply a drop of vulcanizing fluid to the centre of the patch and press onto the tube. Wiggle it around to spread out the fluid evenly. Pull off and wait 20-30 seconds to dry and get tacky. Press patch on and hold for 20-30 seconds.

followed those directions as best i could and STILL no go! the patch stuck but gave before the tire was inflated.

i'm seriously thinking about putting a $100 bounty on sure fire directions for patching one of these tubes. i just hate the fact that it should be possible but i can't figure it out.

and yes, its vulcanizing fluid, at least i trust that it is even though its labeled rubber cement. after all, it came from a patch kit.

and yes, its vulcanizing fluid, at least i trust that it is even though its labeled rubber cement. after all, it came from a patch kit.

I wouldn't count on that.

followed those directions as best i could and STILL no go! the patch stuck but gave before the tire was inflated.

i'm seriously thinking about putting a $100 bounty on sure fire directions for patching one of these tubes. i just hate the fact that it should be possible but i can't figure it out.

and yes, its vulcanizing fluid, at least i trust that it is even though its labeled rubber cement. after all, it came from a patch kit.When you sand the areas to be bonded, you must sand it enough to remove all of the surface layer. So the surface initially turns grey. You must continue sanding until it's black. On both the tube and makeshift patch. Blow off the dust, but never ever touch the exposed black rubber surfaces with anything. Not your fingers, not a rag, etc.

Then get real vulcanizing fluid. There's a translation error somewhere I think where "vulcanizing fluid" got called "rubber cement" in it's functional intent. But then someone got that confused with real rubber cement (temporary glue for paper). At some point, real "rubber cement" got substituted for "vulcanizing fluid". Real vulcanizing fluid, will ALWAYS say "vulcaning fluid":

http://ecx.images-amazon.com/images/I/31DbOxsccKL._SL500_AA300_.jpg
http://ecx.images-amazon.com/images/I/31DbOxsccKL._SL500_AA300_.jpg

There is a certain percentage of stuff that's labeled "rubber cement" when it's really "vulcanizing fluid". But I have no idea what that percentage is. To be safe, make sure you get a tube that explicitly says "vulcaning fluid".

Also don't use acetone to clean, it will interfere with the vulcanizing fluid. .

Absolutely DO use acetone to clean the area before patching. It will leave no residue and make sure that the area is perfectly clean. You just have to be careful to use pure acetone; some cosmetic counter acetone, especially if it's in little packets, has other chemicals that act as lubricants.

With Road Tubeless, you pretty much have to use acetone to clean the tire before patching to get the sealant off.

1) Cleaned it with acetone again. Real acetone. What is the best way to apply the acetone? I used a cotton ball but i suspect there are better ways.

2) Looks like my performance bike patch kit comes with rubber cement but my Rema Tip Top patch kit comes with vulcanizing fluid. The tubes do list slightly different contents. I used the Rema Tip Top this time.

3) Sanding the rubber on the tire produces pilling which i'm brushing off with my fingertip which i'm assuming is okay since i'm cleaning with acetone.

4) Same result.

the tube in question - http://www.performancebike.com/bikes//Product_10052_10551_1034747_-1___

Hardly anybody pays any attention, but I just wipe the tube with Magic Buff or equivalent, apply the vulcanizing fluid and let dry, press the patch down well, and it's done. I haven't sanded a tube in thirty years, and I don't have patch failures. I use the Rema patches, they're so cheap it's not worth trying to make your own from old tubes, plus they have a nice soft rubber surface that goes next to the tube and bonds easily and well, even conforming to seams.
No difference in materials or technique between "thorn proof" and regular tube patching.

Most repair kits come with sandpaper to clean the area to be patched. Some (by far the minority) come with a metal piece (sometimes built into the cap) that looks kind of like a cheese grater. I have had much better luck using the 'cheese grater' to clean the patch area of the tube--it does not wear down, and seems to clean better than sandpaper. Might make enough of a difference in cleaned area to make patch stick--or not.

Rema Tip Top work fine, you need to do surface prep, I substituted a piece of coarse grit Emery Cloth for the small bit of sand paper in the Kits and it has been durable for many years .Carborundum grit is used for metalworking
Garnet grit, [sandpaper] is for wood.

Throw away thorn resistant tube, purchase regular tube, purchase Mr Tuffy liners, insert Mr Tuffy liner into tire, insert regular tube into tire, install tire on rim, mount wheel on bicycle. Ride bike.

Throw away thorn resistant tube, purchase regular tube, purchase Mr Tuffy liners, insert Mr Tuffy liner into tire, insert regular tube into tire, install tire on rim, mount wheel on bicycle. Ride bike.

Tell us how you REALLY feel!:innocent:

Rode a 6 month bike tour from SW Ireland To Scottish Highlands with out a puncture on Thorn resistant tubes .

the overlap in Mr Tuffys move as the wheel rotates and make abrasion punctures.

even after feathering the edge on the bench grinder..

I've run the same tubes as the OP on my commuter for almost 2 years without a flat plus they don't loose air nearly as quickly as standard tubes.

OP, did you try patching them using regular patches instead of trying to use old tubes? As mine have yet to flat I haven't needed to try patching but don't see why they would be any different than standard tubes.

yes, regular patches were tried without success. no, i don't understand why they don't work, but they don't.

If you're going to clean with a solvent, you must do it before you buff, and you must allow time for it to entirely evaporate before you buff with the sandpaper. it would also be useful to pick one that's going to do something useful; try hexane, or lighter fluid, acetone isn't suitable for this. Remove the dust by blowing or shaking or vacuuming. Apply a thin layer of vulcanizing fluid to an area somewhat larger than the patch. Allow to dry; at least five minutes, but it may take longer, depending on temperature or humidty. It's impossible to wait too long for the cement to dry, so if you have any doubt, wait some more. peel the foil off the patch, and iwthout touching the face gum, put in place, and then firmly press it in place. Use the back of a tire iron or something to thoroughly burnish the patch on to the tube. Inflate, observe lack of leak, deflate, reinstall, reinflate.

yes, regular patches were tried without success. no, i don't understand why they don't work, but they don't.

I'm with you on this. I tried patching first, and when it didn't work, I put in a new tube. Much easier than becoming angry at the tire, or thinking the glue and patch are conspiring against me. However, I know that the manufacturers in developing countries are marketing patch kits that sometimes work so that wealthy infadel purchase both a patch kit and a tire. Clever, aren't they!

yes, regular patches were tried without success. no, i don't understand why they don't work, but they don't.

Hmmm, perhaps you have something other than a butyl tube?

I've given up on patching these tubes. and perhaps patching tubes in general. if a patch fails, thats it, new tube.

I've given up on patching these tubes. and perhaps patching tubes in general. if a patch fails, thats it, new tube.

I never had much success patching thorn-resistant tubes where patching regular tubes worked fine. I think it might have to do with the different stiffness of the thicker rubber.

FWIW: I rarely put more than 2 patches on a tube nowadays. If it gets to that stage, I tend to put in a new tube.

I have patched thorn resistant tubes from patches made from old tubes and haven't had a problem, but I do have a regular tube which i cant get a patch to stick to, even the bought patches wont stick to it.


Scott.

I have just been through this myself. Not with thorn proof tubes but normal tubes. All of a sudden my patches wouldn't stick! It was mad. Long story short, the rubber cement needed more time to cure than normal for some reason. I found out that if I kept pressure on the patch overnight with a weight, the next day they would be sealed fine. Had to wrap the tube in paper towel to avoid glueing the patch and tube to my weight (3lb hammer) but once cured, the paper towel can be wetted and falls off.

I tried cleaning and sanding and using lots of glue and other things but the only thing that worked was just letting it dry out in its own time. I used cut up inner tubes as well as patches from a kit. The kit patches do seem to work a bit better but not much.

My advice is to try the overnight thing. Maybe your glue is just not setting like mine. Not sure what caused it all of a sudden, I used 3 different glues with the same effect. Maybe humidity or maybe I don't have a pure soul or something? LOL!

^^ A three pound hammer won't fit in my saddle bag:) It is an interesting thread and makes a point to carry an extra tube on ride if the patch won't work.

I found pressing the patched section lightly between two blocks of wood clamped in a vise overnight really helped my make-shift cut-up-tube patches stick better. They really don't stick as well as the uncured red rubber on the Rema patches.

>>I found out that if I kept pressure on the patch overnight with a weight, the next day they would be sealed fine.

Okay, i'm giving this a try!

The tube inflated fine but failed to hold for more than a few minutes. i waited overnight. grm.

I have just been through this myself. Not with thorn proof tubes but normal tubes. All of a sudden my patches wouldn't stick! It was mad. Long story short, the rubber cement needed more time to cure than normal for some reason. I found out that if I kept pressure on the patch overnight with a weight, the next day they would be sealed fine. Had to wrap the tube in paper towel to avoid glueing the patch and tube to my weight (3lb hammer) but once cured, the paper towel can be wetted and falls off.

I tried cleaning and sanding and using lots of glue and other things but the only thing that worked was just letting it dry out in its own time. I used cut up inner tubes as well as patches from a kit. The kit patches do seem to work a bit better but not much.

My advice is to try the overnight thing. Maybe your glue is just not setting like mine. Not sure what caused it all of a sudden, I used 3 different glues with the same effect. Maybe humidity or maybe I don't have a pure soul or something? LOL!

I believe that a longer curing time is a sign that the fluid has neared/reached the end of it useful lifespan. Depending upon the quality of the packaging for the tube, is it possible that the fluid does get some exposure to the air resulting in loss of intended properties? I know that once the fluid is opened its useful lifespan is shortened. And from what I've read you should replace the fluid even if not opened every 6-12 months, which would imply that if you get an older tube of the stuff on the store shelves it could already be past its useful lifespan.

the fluid i used wasn't more than 2 months old. from the store.

if the theory that it can go bad in the tube is true, how does one guarantee that you have fresh fluid?

the fluid i used wasn't more than 2 months old. from the store.

if the theory that it can go bad in the tube is true, how does one guarantee that you have fresh fluid?

One thing is to never touch the tip of the tube to anything. Some people use the tube as a paint-brush to swab the fluid on. But this creates uneven coverage and due to the long time it takes, the beginning spots will be tacky and ready while the later spots are still wet. The powdered rubber from buffing will find its way back up the tip and contaminate the rest of the container.

I prefer to drip a drop the size of a popcorn kernel onto the patch then close the fluid container. Then use the patch to smear the fluid onto the tube then peel off. Takes 1 seconds and gives you a perfectly uniform layer that will dry evenly. Then press one and hold/clamp until the bond is permanent.