On this year's tour of the Kettle Valley Railway, my friend Roy developed a leak in his rear tire as we pulled into Princeton Castle Resort. Being hungry and tired with a camp to set up, we decided to repair the tire the next day.
The next morning when we inspected the tire, it was discovered that the leak was caused by a gash in the sidewall of the tire itself. Our next step was to pull the tube out and repair the puncture and then look for a suitable "boot" - something tough, thin and having no sharp edges to place between the tube and the sidewall of the tire at the gash.
The problem with the incision in the sidewall is that the cut exposed the steel belts in the tire and that causes the tube to rub against their sharp edges creating a puncture. Given that we were nowhere near a bike shop, we needed to fix the problem right then and there.
We dug around in the recycle bin at the camp and found two possible repair materials - a plastic milk jug and a Tetra Pak. After cutting one rectangular piece from each container (larger than the gash in the sidewall), we decided to use the Tetra Pak as its edges were smoother than those of the milk carton.
So we inserted the tube into the tire which was already half mounted on the rim and then it was a matter of putting the Tetra Pak rectangle between the tube and the sidewall (at the gash). Using our small hand pump, it was no problem pumping it up to the recommended pressure and Roy rode around the camp to test out the repair.
It is important to remember that this is an emergency repair. As soon as possible, a new tire (and for that matter a new tube) should be purchased and used to replace the damaged tire and tube.
As a post script, the repair lasted until we got to Cawston where a new patch had to be put on the tube and the Tetra Pak repositioned.
As a post post script, that repair lasted until we reached Vaseux Lake on the last day of our trip where Roy and I pulled off the highway and put a new tube onto his wheel and that repair got us to our starting/finishing point in Penticton.