DOS

I hereby admit that I am incapabale of patching a tube so it wont leak. I think I am doing it right -- scuff surface, apply vulcanizing fluid, let dry, apply patch. the patches always look nice. But every time, the tube leaks. Not a lot. The tires hold air well enough to ride to work and home again at end of day without need to reinflate. But instead of losing a few pounds of air over 24 hrs, the tire with patched tube will lose maybe 20 or 30 lbs and invariably dunking inflated patch in water reveals oh so slight bubbling somewhere around edge of patch. Since I reinflate every ride, anyway, perhaps this isnt a big deal, but its irritating nontheless. Welcome any advice for patching tubes so they dont leak.

10 Wheels

I air up the tube after patching.

Hang it up and check it after 24 hours.

If it has lost air I water test it, looking for very small slow air bubbles.

FBinNY 

One of the most important steps is to "stitch" the patch down. You can't do this with gentle finger pressure, you need intense local pressure to work the patch into the tube and make a proper bond. They make tire stitchers, which are basically wheels on a stick specifically for this job. You don't need to go out and buy one though. Anything that will let you massage the two together will work. I use the rounded end of a 6" adjustable wrench on a table top, using a rocking motion to do the job, you can improvise with anything, but take a minute and stitch the patch down, especially at the edges and you'll have better results.

BTW- if you use patches like Rema, you're also supposed to remove the cellophane on the outside after you've stitched the patch. The cellophane inhibits the curing process (according to Rema) and prevents good bonding.

BTW- there's also a bit of chemistry involved, and there are slightly different formulations of the butyl in tubes. IME- every once in a while you'll run into a mismatch that won't bond no matter how hard you try. In Germany, Rema offers patches of different material and glue for various types of tubes, but only one (the basic butyl) is sold here in the USA

prathmann

I've found that the 'let dry' step can be important and therefore it's best to do the patching at home without any time concerns. So I carry a spare tube to change the flat on the road (and also a patch kit just in case there are multiple flats). Once I have a few tubes to fix I do the patching at home and let the glue sit for quite awhile to dry before applying the patch. This also allows the patch job to cure fully before it's put into use. And I agree with a previous post that it's best to remove the cellophane covering from the patch.

FBinNY 

+1, I didn't mention this since the OP says he does that, but this isn't a place for impatience. No blowing on the glue to dry it faster, or any shortcuts. As noted, carry a spare, so you can do a proper job at home.

DOS

I haven't been doing anything by way of stitching (just pressing edges down. I'll give it a shot.

Edited to add: Okay, gave the stitching a shot, using the back side of my handy hozan c-205 lockring wrench (https://www.hozan.co.jp/cycle_e/catal...edal/C-205.htm) as my stiching tool. I let you know how it holds air.

dprayvd

I gotta question for my TX & NY bff's:

Do you.all.really use the supplied grater and/or the sandpaper?

FBinNY 

I don't, I have an old paint mixer stick (the wooden kind they used to give away free) with glue-on sandpaper on it.

rjkfsm

I don't even let the glue dry. I give it a minute or two to let the glue get a skin, then I slap the patch on it and press with my thumb and massage it until glue oozes out all the way around. If I don't have enough glue all the way around the edge, I add more from the tube. I then smear the glue around the edge of the patch and cover the orange in glue, wait 5 minutes and inflate with a couple of psi to hold form to re-install.

Yes, it's a messy way to do it, but it works every time for me and it's fast.

RK

dsbrantjr

Don't just scuff the surface; you need to remove all of the original surface of the rubber tube as it is contaminated with mold release compound which will interfere with the vulcanization process. It is not merely glue sticking to the rubber but a chemical reaction which occurs that fuses the rubber surfaces together.

longbeachgary

I'm so bad at patching that I don't even bother anymore.

ultraman6970

Depends on the patches and the glue you are using. I dont even buy patches anymore, i use old tubes and glue for tubulars, that thing fuse the piece of rubber big time.

jolly_ross

Patch at home as others have said. Wise and respected posters have mentioned stitching, you should listen to them.

I, however, am feckless and lazy - so I use a small one of these to clamp the patch tight while it dries, sprinkle talc or ground chalk before clamping so the patch doesn't stick to the clamp.

https://www.rapidtoolsdirect.co.uk/im...ck%20clamp.jpg

Incidentally the little clamp is also v useful for holding v-brake arms together while you do up cable fittings etc.

davidad

I usually patch at home after a ride. I use acetone to remove the mold release and give it a light sanding with emory cloth. I apply a thin layer of vulcanizing compound and let it sit for at least 5 minutes before applying the patch. I work mine in with an old socket.

cyccommute 

I almost guarandamntee that we'll be hearing from RK in the future

RK, you are waiting 5 minutes anyway. Why not just apply a thin layer of vulcanizing fluid (it's not 'glue'), allow it to dry for those 5 minutes and press the patch in place. Permanent fix and you haven't wasted a whole bunch of vulcanizing fluid you don't need to waste in addition to not making a mess.

cyccommute 

Wait. Wait. Wait. Then wait some more. You can't wait too long for the fluid to dry.

Patch the tube flat, i.e. without air in it. Air tends to pucker the patch and, if you have pockets that don't make a good bond...it happens...you'll form channels for leaks.

The quality of the patch kit is important too. Cheap patches aren't worth the box they come in. Buy good Rem Tip Top patches and follow the instruction.

And, finally, wait.

RB1-luvr

I gently clamp my patch jobs in a vise between two blocks of leather for about an hour, then I hang it up with my other patched tubes to be used in the future.

ursle

The surface you set the tube on to roll the patch has to be solid, I like vices that are rounded,, and roll it hard, get all the air out from under the patch and mush the patch on.

Yes anything will do but use the correct tool, a roller, it's what makes life fun.

As it's contact cement, the longer it dries before joining, the better the bond

Clean both surfaces with an alchol swipe before applying glue

rydabent

I hate to tell you guys, but you are using an antique way of patching tubes. I use Park glueless patches. I have NEVER had one fail. I am riding right now on tubes that have had the glueless patches on then for more than 2 or 3 years. All I do is scuff the leak area well, place the patch on and remount and inflate.

Ridefreemc

In addition to the suggestions above, I will inflate the tube just a little so that it gets to the shape it might take inflated inside the tire. That way, especially on large volume tires, there is less stretch of the tube and patch after inflation.

This doesn't always work - especially if it is a large hole - then the air escapes and ruins the patch. YMMV.

RB1-luvr

I've had bad luck with these and won't use them anymore.

dprayvd

FB, fair enough.

pmt

Listen to FBinNY; he knows what to do. There is no substitute for real Rema patches, or in the case of Road Tubeless, the larger car tire patches and the can of blue fluid.

rpenmanparker 

This is really good advice. I have used a wooden roller intended for sealing wallpaper seams. And the comment about Rema is right on too, execpt it is a catch-22. Sure you should use Rema, but getting the cellophane off causes me to spoil more patch applications than I can count. Pulling off the cellophane too early or too roughly is a prime cause of a poor seal; it undoes all you hard work.

Having said all that about technique, I am going to go out on a limb and risk some ridicule. It is wasteful I know and not very bike-macho, but if you can afford to toss the tube, just do it. The is no glory in always worrying about your tubes leaking or failing on a ride due to a bad patch. For $4-6 on sale, after riding road bikes for over 30 years, I just don't need the aggravation any more. If you can't afford it, I certainly do understand. Been there too. In that case all this other advice is right on, but you will be happier if you can just blow it off. What I do is carry the glueless patches for an emergency just to get me home in case I really screw up and go through my couple of spare tubes (like not checking for sharp objects in the tire casing). When I get the patched tube home, it goes into the wastebasket. Done and done.

Robert

MichaelW

Use patches with a feathered edge like rema.
Clean, sand, apply THIN smear of cement over area greater than patch, centred on the hole.
My LBS advised 2 very thin coats.

wait
Apply patch to exclude air. I bend the patch, contact with the centre and let it roll out. With smaller patches, you can roll them on from one side. Apply thumb radially from centre to edge, quite hard.
Remove paper/cellophane by cracking the material in the centre and peeling from centre-outwards.
Any force from the centre inwards will act to raise the edge.