Poor patching job on a bike inner turb
March 21, 2012 11:01 AM   Subscribe

So I tried to patch a bike tube on my lunch break and I apparently didn't spread enough of the vulcanizing agent. Is the tube ruined?

Because I didn't spread enough of the vulcanizing stuff, the edges of the patch are still free--as a result, the plastic on the back of the patch won't come off without taking the patch with it. I figure I have a few options, but I don't know which one is best.

1. Rip the patch off, and reapply the vulcanizing agent and a new patch, after re-roughing the area.

2. Apply more of the vulcanizing agent around the edges of the patch. Given that you're supposed to wait five minutes before applying the patch, I'm not sure if this will work.

3. Just leave the plastic on the patch and keep this tube in my office as a "worst-case scenario" option.

4. Get rid of the tube.

Any ideas on which one of these options is the best? Anything I'm missing here?
posted by thecaddy to Sports, Hobbies, & Recreation (14 answers total)
I've done this before, and just smeared some more glue around the edges and left the plastic on. I didn't notice any drawback to this.
posted by RobotHero at 11:03 AM on March 21, 2012

I'd get a new tube and some glue-free patches on your lunch break. Option #1 is really the only viable one otherwise and should be OK.
posted by kcm at 11:03 AM on March 21, 2012 [2 favorites]

I would say either reapply a brand-new patch, or use a new tube. Tubes are pretty cheap. I usually don't bother patching when I blow one out, unless I'm in a tight spot where changing the tube would be hard.
posted by deathpanels at 11:06 AM on March 21, 2012

Someone may correct me, but I always consider a patch to be a temporary fix until I can get a new inner tube. Take option two, and try and make it to the bike shop to buy a new one. It won't cost you more than $10, if that.
posted by Think_Long at 11:07 AM on March 21, 2012

@Think_Long is right. I always keep a WalMart spare tube as my "oh, crap, gotta get home!" spare. Usually doesn't cost more than $5.
posted by chrisfromthelc at 11:11 AM on March 21, 2012

You don't need to remove the plastic from the back of the patch. It won't make any difference at all to leave that on there - I never bother to remove it. I'd go for option two (squirt some goop in there, then wait a few minutes before pressing down), or possibly just trying it out as is, if it looks like the actual area with the hole is bonded to the patch.
posted by ssg at 11:24 AM on March 21, 2012 [1 favorite]

Meh, if the patch closes the hole already, you just as well can roughen-glue-tap it down around the edges some more.

In the old days, we sometimes would stick patch over patch. Sometimes it worked, sometimes we would find out that it didn't. Answer to Think_Long: to the queasy of mind, your solution is best. But I've seen patches hold for decades.

And those who say a new tube doesn't cost much are even righter. At the end it's all about being adventurous. To get a faint taste of what this means, leave the plastic on and all that, assemble your tyre after checking that no piercing whatevers are still stuck somewhere, and try biking home on it after work, however planning your route past a bike store to get a new tube.
posted by Namlit at 11:28 AM on March 21, 2012

number 1.

don't use glue-free patches. they suck.
posted by entropone at 11:55 AM on March 21, 2012

I'd go with option 1, but then again I love glue free patches and think they are awesome. Last tube I tossed had six (SIX!) glue free patches that held strong for years. I finally decided that tube had enough miles.
posted by Big_B at 12:53 PM on March 21, 2012

Any of 1, 2, and 3 will be fine.

#4 (getting rid of tube) is quite unnecessary if you install the tube immediately.

When inflated within a tire, a patched tube will be MORE durable (not less) in the patched area than anywhere else. When stored un-inflated, patches are liable to come off...especially if you fold the tube. Needless to say, inflating a patched tube when it's not installed in a tire will blow the patch off.
posted by wutangclan at 12:54 PM on March 21, 2012

I'd try #3 first. Put the tube back in the tire and see if it holds air. I keep my pristine tube for emergencies and use my patched tubes daily.

I work in a bike shop and get discounts on tubes, but I still commute on tubes that have about ten patches between them.
posted by spikeleemajortomdickandharryconnickjrmints at 2:21 PM on March 21, 2012

It doesn't matter if the edges come up a bit. Once the tube is in the tire, pressured up, the casing of the tire will hold the patch against the tube and it won't come up any more.

There's also no reason to remove the plastic backing from the patch itself.

You probably know this, but it needs to be reiterated: let the vulcanizing fluid dry completely before you put the patch on. Seriously. It makes all the difference.
posted by klanawa at 4:26 PM on March 21, 2012

I usually do either 1 or 2, depending on how bad it is. You can put as many patches on a tube as there are places to patch it.

Reasons to no longer use the tube as a tube include: the valve rips off or the hole is bigger than the patch. However, instead of option 4, you can use the expired tube as a bungee cord to hold things onto your bike rack.
posted by aniola at 5:11 PM on March 21, 2012 [1 favorite]

Leave the plastic on the back of the patch if you like. There's no advantage to removing it.

A properly patched tube is tougher in the area of the patch than an area of as-new tube, so there's no reason to consider a patched tube inferior to a brand new one.

If it were me, I'd go with option 1. Patches cost pennies and it's worth doing the job right.

Remember to roughen the area around the hole with the grit paper supplied in a patch kit or similar. This is the most essential step for patching success. Make the roughened area larger than the patch and apply solution over that whole area. The goal is to have excess solution all around the patch and thus avoid the unstuck patch-edge problem.

Be patient and wait a few minutes (I find 4-6 is good) before applying the patch after applying the solution to the tube.

Trashing tubes rather than fixing them is not only expensive, it undermines any environmental virtue you might claim as a cyclist, if that matters to you.
posted by normy at 11:01 AM on March 29, 2012

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