Bicycle Mechanics - Tube patching on seams

I'm having trouble patching a tube when the puncture is close to a seam in the rubber. When I apply the patch, the seam makes a small air pocket, which eventually lets air escape when pressures are high enough and enlarges the air pocket to the edges of the patch.

Is there any way around this? I have 3 tubes sitting on the floor right now, with patches on them, and they all leak because all the punctures are close to seams.

Please help ... :(

Sand down the seam as flat as you can get it. Works for me every time... I'm assuming you're NOT using one of those glueless patches, correct?...

Yes, they are the preglued stuff.

if you have a vice or a way to really clamp down on the tube you can overcome this problem.

I used to use a vice and some flat pieces of wood to sandwich the tube/patch. or you can use a C-clamp and a few pieces of wood.

After trying to sand down a couple of seams, it seems like it'd be easier and cheaper (timewise) to get another tube for $2.50. :p

I've never found self-adhesive patches to be reliable. Standard patches with the cement that comes with them work on seams or anywhere else; it pretty much becomes the rubber, and the patch becomes the strongest part of the tube.

RichC

Mr. Chi.............on the road, I carry both traditional and glueless patches, just in case. I use glueless patches only over easy pinhole flats only. Of course, I carry an extra tube with me and I will just replace the tube first.
But at home, I patch all tubes using traditioinal patches.

I vote for the glued on patches. I had a 100% rapid leak down rate with Park
glueless in '97-98. Then stopped patching and bought new tubes for 2.5 yrs. When I noted that I had 17 tubes in the basement with unpatched holes I took advantage of a Performance sale on patch kits and bought 20 for $10 and have patched ever since. I use Walmart patch glue: 8oz for $4 with a brush in
the can and sand down heavily on seams and use larger patches over seams. Seams are everywhere on tubes, or mold flashings. Patches rarely leak with this approach but I double check by using a dinged rim to mount the tube in a tire and pump it up and leave it for a week or so. If it holds air it goes into the good patched pile. Steve