noahjz

I was searching through some threads on tube patching, hoping to stumble across some gem which would improve my tube patching success rate which is pretty abysmally low, less than half. I was pretty surprised by how many posters are able to patch their tubes with very low failure rates. A lot of people seem to have been patching for years and have only had a few patches fail.

I only recently started patching my tubes, using a basic patch kit, I am pretty sure my procedure is the most common one, sand around the puncture spot, apply vulcanizing glue, let it get really dry, put on the patch (the ones I use have adhesive backing), apply pressure for maybe 5 minutes or so. What step here do you think is the one most likely going wrong for me? I know some people use clamps for putting pressure on the patch, and maybe that is what I need to try, since I just use my fingers which do get tired after applying pressure for several minutes at a time.

I also think I might not be putting enough glue down, since the glue is supposed to cover an area which extends a little beyond the area of the patch, so that the edges of the patch are firmly affixed... the problem is the patches tend to be bigger than the width of the inner tube, so to get enough glue down I would have to go around the tube, which is problematic since the tube is usually sitting on a table. I'm not using extra-large patches or anything, but road tubes are just not that wide. Do people sometimes cut their patches in half? I would think this would work, as long as the patch fully covers the puncture. Otherwise do I need to suspend my tubes somehow so I can apply glue to the underside?

To be clear, most of the flats I get are from running over small pieces of glass or misc. construction detritus, I very rarely get big tube blowouts and I don't try to patch these. I have noticed that I seem to have better luck with schrader tubes than presta, but this could be coincidental.

Anyhow I would appreciate any words of wisdom, since I tend to get tons of flats. Is it just me or are tubes getting pretty expensive? I feel like not too long ago they were ~ $4 a tube, now most bike shops seem to be at $6?

cyccommute 

When you apply the glue, roll the tube in your fingers (I hold the tube in my hand) so that the glue area is larger than the patch. This is really important on thin tubes since the patch is often larger then the tube diameter. You really want to make sure the edges of the patch are in the glue.

You may be missing the hole too. After I find the puncture, I mark the hole (and check to make sure I got it) then sand. I apply the glue in a circular motion and make sure it's larger than the patch. You really shouldn't have to hold it with clamps to make the patch stick.

bikeman715

sand then clean the area with rubbing alcohol let the glue dry for 5 mins. use the palm of your hand to put pressure on the patch .

Camilo

Just to make sure - you're removing the backing from the attchment surface of the patch?

I've never had to hold pressure for 5 minutes. I have only firmly pressed the patch onto the glue, making sure it's firmly pressed on the edges especially.

Patch sounds WAY bigger than a normal bicycle patch. The ones I use come in a tiny plastic box with glue and sandpaper and are about the size of a US dime or nickel. They are either round or oblong. The oblong ones are about the size of two of the round ones. The round ones especially are very easy to fit on a normal road bike tube, certainly on a mtb tube as well.

It's fine to cut the patch. It just won't have the nice tapered edge which means it might snag and get yanked off easier. Shouldn't be a problem because (1) it should be glued firmly and (2) there's no way to snag it once it's installed.

I don't think schraeder vs. presta can possibly be a factor.

twobikes

I used to patch tubes. It worked most of the time. Lately I have had the same problems you are having. I, too, think I am doing things right. Still, it is frustrating to spend the time taking the wheel out of the bike, taking the tire and tube off of the rim, etc. and then have the thing leak when it is patched and all back together. I find the smaller frustration and time saved dismounting the tire and tube yet again worth the price of a new tube. Add to that my tube of cement usually dries out before I get a second use from it.

Retro Grouch 

I think so too. The patches in most of the patch kits that you buy are just too big. If the patch is so big that it sticks over the edges on a flattened inner tube, I cut it down.

Since I only patch tubes in my shop at home, I put them in a clamp for awhile to set the glue. Other than that, I do it exactly as you described. I can't remember one of my patches leaking unless it was either too close to the valve stem or overlapping another patch.

I used to patch a lot of tubes. These days I only get one or two flats a year so I'm sometimes guilty of just replacing and pitching the flatted inner tube. I won't pay $6.00 for a tube. The last tubes that I bought were on some Performance sale deal. And yeah, Performance house brand tubes suit me just fine. Like I say, I only get 1 or 2 flats per year so how bad can they be?

milnerpt

I dont put enough glue on, use too big of a patch, the ends arent securely fastened, and dont hold it 5 minutes and I never have problems. I do sand it pretty well, though. I would look above and make sure you are getting over the hole well.

Also, when your patches 'fail', do you pull it out and look? is it a new hole, does the patch come off? I mean, what do you consider a 'failure'?

noahjz

After I patch the tube I fill it with some air and let it sit around overnight. If it is empty again in the morning it is a failure. I have yet to try and "re-patch", is this possible? If so do you take the ineffective patch off? This seems difficult... anyone have a technique for getting them off?

The sand paper that came with the kit seems pretty smooth, what grade sandpaper do people use?

Oh and yes, I DO take the sticker off which protects the adhesive. I am a pretty big idiot, but I am not that big of a pretty big idiot

Thanks for the help everybody

mparker326

I just take my fingernail and peel back the edge of the failed patch, pull it off, resand, and try it again.

Have you also tried a different patch kit? I've had better luck with LBS kit patches than Target kit patches.

mentat6059

try using patches without the self adhesive on the back. sounds like the glue is sticking to the adhesive and then the adhesive is peeling off the patch so you are not actually gluing the tube to the patch

cyccommute 

Filling it with air may be part of your problem. Although the patch will stick to the glue (if properly dried) instantly, it takes some time for the bond between the patch, the glue and the tube to cure. Pumping air into the tube stretches the tube but the patch, being made of a different material, doesn't stretch as much and can be pulled off the hole. You've probably noticed this whenever you pump up a patched tube.

The best way to treat a tube is to patch it, fold it and put it into a plastic bag until you need it again. That way the patch will cure and make a stronger bond.

I use around 200 grit sandpaper when I lose the sandpaper that comes in the kit...which is around 60 grit.

Repatching an old patch can be difficult. If you peal it off, you end up with an unsmooth area on the tube. Leave it in place, do a water test and find out where the leak is coming from. Then put another patch over that area after going through the whole sand, glue, dry routine.

StanSeven

I gave up a long time ago. I had patched tubes laying around for years and never used them. New tubes are maybe $2.50 each on sale. I get maybe two flats a year having learned to always waer cycling glasses and watch for galss and other debris. I figure that $5.00 annual cost for piece of mind not worrying about whether a ptch held is wise

WalterMitty

Since you're getting tons of flats you might look at your tire condition/selection, but that's another thread.

I haven't had a patch fail in decades, and that includes bicycle tires, automobile tires, truck and farm tubes (going back a while), vinyl patches on things like air mattresses, basically everything that holds gas or liquid that can get a hole in it.

The first, or most basic, "secret" is that you have to realize that the area around the puncture is contaminated and will not bond well with any adhesive. (you can't even get a reliable bond with the patch material using hot vulcanization or other fusion techniques, but that is also another thread) This contamination is not just a "surface" layer that can be wiped or washed off; you must actually remove the top layer of the area to be patched because the contamination permeates the outer layer and will form a weak bond layer that will easily split if it doesn't leak instantly.

I usually inflate the tube to about 2X its normal size to help me control the area and help keep it flat. Sandpaper does a poor job because it loads up quickly with contaminates and will actually smear them back into the cleaned area and add contamination of its own due to physical degradation. Adding insult to injury, some papers will embed contaminates ("sand" particles, fillers and failed adhesive) into the repair area that will guarantee poor adhesion everywhere it sticks. Emery paper is slightly better, but I favor the old-style metal rasps that cut and scrape the surface clean. If you will keep the rasp cleared of build up you can get through the surface layer and into virgin rubber pretty quickly. When done correctly the repair area will be significantly and uniformly darker than the surrounding untouched rubber. If a mold flash line (ridge) is in the area it must be made level with the repair area or it will create a leak path.

With the area clean and the tube still inflated to about 2X size I apply the adhesive to the repair area. (bonus: the glue will indicate if I'm working on an area with a hole it it) If I'm using old cut up tubes as patches I glue them too after subjecting them to the same cleaning. If the patch is pre-glued I don't add any more to the patch.

Once the glue on the tube is dry, I manipulate the inflated tube so that the repair area is roughly the same size the tube will be when inflated or slightly larger, and I firmly press the patch in place. I will press and work the two pieces together to ensure full contact between the components for a half minute or so. If it's been done right it will take, if not, no amount of time or pressure will change that.

If you're by the side of the road, let the tube rest while you put your stuff away, then deflate the tube and put it in the tire (you *did* check the inside of the tire for sharps right? Label on the tire is indexed to the valve stem and the tube is layed out on the tire with certainty that the object is no longer sticking through the tire?) pump it up and ride on.

If I'm fixing tubes at home I use a Dremel (warning: you may go through a couple of tubes before you get the hang of buffing with power tools) and may let the tube hang overnight before I put it back in the tire, but it really doesn't matter.

If you can get your method down on getting the repair area clean, you'll tear a tube in half before you can peel the patch back off that's been applied with rubber cement. Of course, practice at home on some lazy Sunday afternoon is more conducive to perfecting your methods than trying to remember everything by the side of the road with traffic wizzing by.

powers2b

The key is to let the glue dry to a haze.
You should be able to touch the glue with your finger and pull it away clean.
Then apply the patch and hold down with your thumb for about 30 sec.

DiabloScott

I have about an 80% success rate with patches.

I only do it at home and I don't put patched tubes in my saddle bag, only new ones. (probably just superstitious).

I keep tubes that need patching hanging from my garage until I have three or four to do at once.

Sanding is to remove the "mold release" from the tube, it helps to think that you're scraping off a coating instead of just "roughing up" the surface. The glue doesn't bond well with the coating.

My biggest error before was trying to put the patch on while the glue was still wet - now I usually give it about 5 minutes before I put the patch on, but you can blow on it and speed this up a little.

I have an old wheel and tire to use for checking success. After the tube and patch are complete, I mount the tube in the old wheel and pressurize it to 120 or so; then check after a half day and see if it went soft - may or may not try another patch if it did. If it did hold pressure then I move the tube over to another hook in the garage where all the tubes have passed the test.

It's much easier to just buy new tubes, but patching is kind of fun.

MichaelW

I sand , clean and dry the area, apply a thin smear of solution and let it dry for a couple on mins til tacky then apply a 2nd layer. The key is to keep them very thin.
Good patches have feathered edges which should not be cut. When you apply the patch, press from the centre to the edge with your thumb to ensure no air bubles and leave for a minute.
Crack the paper film by folding the tube across the centre of the patch and press gently till the paper splits. Repeat at right angles to create a cross of torn paper then peel the paper the centre to the edge.

tellyho

Yeah, a good understanding of how vulcanization really works is important to technique. Surface prep seems to be 90% of the whole deal with most of the projects I undertake: repainting, gluing, patching, etc. Sand, clean with alcohol, patch.

Podolak

I know it has been suggested but really, just carry a spare tube with you, they are cheap. Next to that buy some Kevlar tires to reduce the number of flats. Just recycle your old tubes and don't worry about repairing them. Still carry a patch kit though in case you get a flat, use your spare and then get another flat before you get home.

Ol Danl

I've been reading this thread because I have had very little success patching tubes in the past and have one I need to try to patch now. I appreciate the tips y'all have given -- maybe they'll help me too. What about when the patch has to go over a seam in the tube -- does that still work for most of you all? With respect to the tube prices, I seem to remember in the late '70's I could get a mediocre tube at Sears for $2.50, but a decent tube at a bike shop was more like $3.50. Considering the way other prices have increased in 30 years, $6.00 doesn't seem that bad -- although I look for sale prices, too.

cyccommute 

Never had a problem with it. Punctures at the stem are about the only thing short of a blowout that will kill a tube.

MichaelW

You can sand down the ridge form the mould for a smoothe surface but its never been a problem.
I usully carry a spare but have had to do roadside patch repairs a couple of times, sometimes in the rain at night.

tollhousecookie

DUUUUUDE !! I'm an avid patcher and self proclaimed cheapskate...buy new tubes HA ! Here's what I do in a nut shell.......Rough up the spot. put on plenty of glue bigger that the patch size. Put glue on the patch too. THEN I use a hair dryer to dry and heat up both glue globbs and when it's lookin ready. Clamp the bajeebies out of it. After drying time, inflate tube by it's self and check out the patch streeeetching. If it is not a picasso dont hang it on the wall. Maybe sometimes I might stick it in a bucket of water to check for leaks. It does take a little practice to get the feel for it. But sucess is a slap in the face to all the tube buying fool out there. Give it a go Bro................

noahjz

well i just finished up a batch of tube patching... looks like i am at 4/5 which is a big improvement for me. i would say that key things i changed based on all the advice received was:

1. did a much more thorough sanding job.
2. cleaned sanded area with rubbing alcohol. (side question: how do you apply the rubbing alcohol? kleenex deteriorates onto the tube as you rub, are cotton swabs better?)
3. used smaller patches (cutting if need be) to ensure that...
4. patch was smaller than glue area

anyhow thanks again, i do appreciate the advice

Paniolo

To me it sounds like a big part of your problem is patch size. If they are wider than the diameter of your tube it is much harder to get the patch to stick. Surface prep is important. I just smear the glue in a circular motion on the tube, let it skim dry so it is dry when touched with a finger tip and apply patch with finger pressure. Hold for a min or so, maybe using pressure from a tire lever, and it's ready to go. It does bond better if left to dry overnight or longer, but I have ridden plenty right after patching. You want to use the little round patches like in this pic ... you can usually buy sheets if you want from your lbs service guys. The longer rectangular ones suck for 23mm road tubes.

waldowales

I'm a lazy old coot. I've patched hundreds of tubes, from 16" bikes to heavy trucks and farm tractors, and I haven't sanded a tube in the last forty years. Most auto part stores sell a product used to prep tubes. Magic Buff is one, NAPA calls theirs Liquid Buffer. I buy a pint every ten years or so, put an ounce or so in a small plastic bottle, and carry it on the bike. To patch a tube, clean the area around the hole with the liquid on a paper towel, smear on a thin coat of cement, let it dry a couple of minutes, apply the patch and press it down. The only failure I can remember was when I missed the hole with the patch.