So I bought some nicer patches and cement from Amazon. < $20 for the whole thing, a big can of cement and 100 patches. About the cost of 3 or 4 tubes, and I've already used two in the last month, so the payoff is very quick on these.
Here's the new patch (round) versus the old Harbor Freight patch (square). As you can see, the new patch has tapered edges and blends right down to the tire so it should inflate better without getting caught.
here on Amazon, and the patches are here.
If you have never patched before, or if you've had bad luck in the past, here's a quick and easy guide. A properly done patch is very strong and will never leak - I've ripped tubes when experimentally seeing if a patch could come off before.
BTW I'm not a believer in self-adhesive patches, except as an emergency side-of-the-road measure to be replaced by a REAL patch when you get home again. I've never had a proper patch leak, but every self adhesive patch I've put on has failed eventually.
- Locate the hole by inflating the tube - mark somehow if necessary to find it again (marker or whatever). Deflate the tube most of the way.
- Scuff the area to remove any powder or dirt and to give the cement some 'bite' into the material. You can use sandpaper or a scuffing tool if your patch kit has one. I improvise with pushing it hard against carpet and rubbing or even scuffing against pavement while pushing with my thumb.
- Apply a small amount of rubber cement. I usually just put on a dob then smear it with a fingertip. Be sure to cover an area LARGER than the patch - be generous here. You don't want a corner to not be stuck down.
- Set the tube aside and let the glue dry for 5 minutes or so. It should be very tacky, almost set before you put the patch on.
- Finally, remove the backing from the patch and stick it down. Start in the center and SMASH that sucker in with your thumb, working from the inside out to push out any bubbles.
- Ideally let it sit for an hour or so before reusing, but if you're on the side of the road without a spare tube, you can just chuck it right back into service - the air pressure will smash it into the tire and help it cure.