Originally Posted by
Tony N.
...I to use to have no trouble patching tubes but now I have no confidence. For me I patch exactly following the directions. Maybe right away or several days later, I install the tube and begin to fill with air. At about 60 psi or so, the patch will let go.
Are your tubes perhaps stretching greatly to fill the inside of the inflated tire? This would tug at the edges of the patch, so can eventually lead to a creeping failure of the bond surface.
How about your sanding procedure? Are you getting it sanded down to a very dark flat black? Are you fully sanding down the seam lines?
The glue is best applied with a piece of plastic bag stretched over your finger. Also, the glue needs to be fairly fresh, and needs time to etch itself chemically into the rubber surface. The glue should thus be spread initially in a thick enough layer, slowly so it doesn't go dry quite so fast, and the glue spreading should stop before the surface tacks up.
Lastly, never breath on the glue, the glue attracts and absorbs moisture that can compromise the bond (this is much better known in the auto/truck tire repair world).
Always allow plenty of time for the glue to dry completely before applying the patch, or the patches may fall off.
And, I'll say it again, some tubes have a gummy texture and do not abrade cleanly, even after much continuous sanding. Such tubes aren't the best candidates for repair.