I never had any luck the first couple of times I tried to patch a tube, so I gave up on it for years. When faced with a flat, I just put in a fresh tube but have still been saving the punctured ones. It's a quiet night so I decided to try patching again. I used one of those kits with the separate cement/vulcanizing fluid, not the quick stick-on patches.

One problem I had was that I didn't realize how big the patches were in relation to the width of the flattened tube, so there's a bit of the patch's edge that isn't bonded to the tube because I didn't spread the cement over a large enough area. Will this be a problem or cause of a leaky patch?

I've also read that a patched tube will sometimes appear to hold air when inflated freely outside a tire but then will actually leak when installed inside a tire. So should I take out the fresh tube and save it for emergency roadside flat replacement and install the patched tube to ride on? When I'm out riding, I don't want my spare tube to be a leaky one!