For micro holes, I've had to hold the tube under water for 20 or 30 seconds before the first tiny bubble showed up. There's always a few surface bubbles clinging to the tube. Wipe them off with fingers, then see if a new bubble eventually reappears!
I had no flats at all in 4500 miles last year! Most years, I might get a sliver puncture and one or two pinch flats. These pinch flats are almost always on good, smooth roads, where I'm not watching carefully enough to see the one sharp cornered rock or metal bit in the road.
Batches
I like to use up a whole tube of glue, instead of trying to keep it after opening, or even after storing unopened for a couple of years. So batch patching works for me, usually 4 or 5 tubes. And it must be more efficient, with everything laid out and the technique repeated on each tube.
My silver sharpie line goes all the way around the tube, and there's a crossed line for a couple of inches along the tube length. Then it doesn't get worn off by sanding.
I like using real sandpaper strips (usually 100 grit) instead of the cheap sandpaper that comes in the patch kit box. And the box itself is a good base for the sanding step -- with the tube stretched a little and pulled down on both sides of the box.
I've clamped the patches overnight with some spring clamps, since I had them, but I don't know if it helps at all.
Last edited by rm -rf; 04-22-21 at 07:51 PM.