So I got a puncture, about 1/8 inch from an existing patch. I use "Rema" patch kit. Is it worth trying to patch a hole that's so close that my new patch will overlap the old one? I'm enough of a tightwad to save the tube if possible, but also don't want a guaranteed flat on my next time out.

If you've removed the plastic film from the old patch and scuff it up along with the surrounding tube, the new patch should hold.

Yes, if you do a decent job blending in the old patch, it should work. OTOH- the edge of the old patch being so close to the puncture that if not well blended in it can become a channel for escaping air.

I'd do this if I were on a tour and needed to recycle my tube stock. If at home, I might also do it, but not as a spare. My rule is anything shaky or borderline is used first, and the best are used as spares. The thinking is that if the bad one goes, I still have a spare I can count on, but if the good stuff punctures and the spare is shaky, I'm walking.

Don't worry about if it's likely to succeed, just give it a try!

Not worth the trouble in my opinion...

I can find new tubes for $2-$3 when I have the time to look in advance (and if I run out, there is always Walmart (Bell brand tubes are $5, or REI for $7). I've had very good luck with a minimal number of flats over the past 20 years. And I have become very good at patching tubes due to lots of practice when my kids were young and they seemed to get a lot of flats). My rule for tubes is: patch no more than twice, and discard if patches will overlap, or when the tube starts cracking anywhere regardless of the age.

Since you are using the REMA patches, there shouldn't be a problem.
If you were using an X-mart type patch kit, forget it.

Sure, it can work. Make sure the cellophane is off the first patch, and proceed as usual. I've repaired a two inch long tear in a tube, using a number of 23mm rema round patches, which over lap. Doesn't leak at all.

Thanks for the tips, folks!

Some of my old tubes are polka dotted with patches. If this were mine, it would soon be new rubber bands, of various sizes and strengths; and, additional bar wrap liner.

I usually leave the cellophane on as it wants to pull the patch off with it when I try to remove it. Perhaps I just need to let the patch cure a bit longer. Except for overlapping patches is there any reason to remove it? The cellophane makes it easier to handle the patch but does it serve any other purpose?

There's a score mark on the Rema patch cellophane. If you fold the patch along the score mark, the cellophane will split open. You can then remove the cellophane from the inside out and not pull up the patch edge.

I'll usually start the slit before applying the patch. I'll line up the slit to be perpendicular to the long radius of the tube (the 700c side). That makes it convenient grip the tube and expand the slit to completely cut the cellophane into two halves.

I'll use scissors to snip a cut on the cellophane edge, if I cannot find the slit. I'll do this before applying the patch. It's sometimes difficult to see the score mark, especially in dark light.

Yes, the celophane has a purpose, otherwise Rema wouldn't spend dough on it. The cellophane works with the foil to keep the glue from drying. Removing it is necessary after the patch is applied, to speed curing and form a permanent bond. Rema also recommends "stitching" down the patch to improve the bond. They make a tool for it but you can do the same by rolling the rim of a cup or dish back and forth all over the patch. Stitching also shatters the cellophane which will mostly fall off by itself.

I've always left the cellophane on. Next time I patch the tube it easily comes off because of patch stretching.

And the purpose might have more to do with ease of manufacturing and storage and less to do with patching. Nonetheless, thanks for the good explanation and "stitching" tips.

As long as the entire area to be covered by the new patch is scuffed (including the back of the old patch) and the glue is applied and left to dry before applying the new patch, it will work.

People who insist on buying a new tube every time they run over a piece of glass are tools of the doghouse makers.

+1 to above.

It helps to roller the new patch down after applying it to help it seal any possible leak paths particularly when patching over parting lines or near an adjacent patch. There are tools for this that are a narrow wheel with a handle that you can roll over the patch repeatedly but you can use anything handy that will apply a localized force on the patch.

Amazon.com: Wooden Handle Repair Patch Tyre 1 1/2" Dia Roller Tool: Automotive

It works just fine for me.

I use the tubes till the valves wear out.

To remove the clear plastic backing just lightly scuff a line across the center of the plastic and fold the patch which should create a tear in the plastic. Pull the plastic off from the center tear to the outside of the patch. This eliminates pulling up the edges of the patch.

The only failed patch I ever had was from this.
So now I don't even try it anymore.

I've done it successfully.

You can also rip off the old patc.h and apply one of the longer, rectangular patches over both holes.

If you can rip off an old patch, it wasn't applied correctly. Done right, the patch to tube bond as as strong as the tube itself, and any attempt to rip the patch off is likely to tear the tube with it.

......when the tube with new patch is inflated in the tire (100 + lbs)psi,the cellophane lets the new patch slide against the interior tire liner...this keeps the patch from getting friction and being pulled up-sort of a lubricant. But as stated above, Rema does say to remove cellophane and apply talc to prevent friction.

Most people don't let the glue dry long enough before installing patch,also put pressure with thumb for longer period of time.

Agreed. I actually tried to rip off a patch on another tube where the air followed a channel formed by marking the hole with a Sharpie marker and not sanding it down enough. The patch and the tube were like a single material.

I dislike sanding. It is too easy to get poor results. Cleaning the tube with alcohol or simple green works so much better. It quickly and completely removes the pen markings and the mold release and leaves a totally black finish that is ready for the vulcanizing fluid. What is really convenient is the alcohol wipes from a pharmacy, they come in a big box for a buck or two. Easy to store on the shop shelf or a in a patch kit.