Len, I completely understand what you're saying. Years ago I used hot vulcanizing patches on motorcycle tubes where you clamped a special patch assembly to the tube and lit the fuel wafer in this thing, which melted the patch onto the tube. That was hot vulcanizing. I believe "cold vulcanizing" is supposed to be the next best thing, where the "cement" is a rubber adhesive whose volatile component is an aggressive solvent that also melts the rubber, thus creating a homogeneous bond. I Googled "cold vulcanizing" and came across a forum discussing the joining of rubber conveyor belts using both hot and cold vulcanizing. In that particular application the strength of the joint is very important. However, in the case of patching a bicycle tube, so long as the bond withstands the handling until the tube is inside the tire and inflated, it's good enough because the air pressure keeps the patch compressed between the tube and the tire casing. Unless you run your tires very soft, the patch will not come loose. It's not even subjected to the rapid flexing resulting in high temperatures that occurs in car or motorcycle tires.
I also doubted that the rubber "cement" used for paper was the same stuff as the rubber "solution" found in patch kits. (When I started patching tires in the UK, it was called rubber solution.) However, I wonder now if the rubber cement used for paper may just have been the same stuff as used for tubes and someone just discovered that it worked for paper and the excess around the edges could be rolled away with your thumb without leaving a messy "glue line".
Anyway, I've now found that the rubber cement for paper works just as well as what I've found in patch kits and can be found in any stationery or art supplies store. My original quest when starting this thread was to find something that worked after I had dismal results with some non-flammable "Tru-Flate Universal Cement" I picked up at a farm supply store. I was of the impression that the old style rubber cement had become environmentally incorrect and hard to find. I now know that rubber cement for paper works as well as the rubber cement that's in patch kits and cold vulcanizing cement works even better if you can find it.
-- John Betmanis Woodstock, Ontario Canada
On 20/07/2010 2:56 PM, Leonard Diamond wrote:
> I guess its hard to argue with success but I always understood the liquid in
> patch kits to be cold vulcanizing fluid and not rubber cement. The
> difference being that the vulcanizing fluid partially melts the rubber
> allowing the patch to meld with the tube as opposed to stick to the surface.
> A quick google search show a place in Rockaway NY called Patchboy that will
> sell you an 8 ounce can (with brush) for $9.19. If you keep the top tightly
> closed it would last quite a while so why bother with rubber cement which is
> primarily for paper?
> Len Diamond
> Ridgewood, New Jersey USA