Polyurea Tire Patch
One of the rear tires of the tractor has a bad spot. At some point a stick stuck through the face of the tire causing us misery. It has been getting worse for a couple of years. We put in a tube and that has kept us going another two years. The hole in the heavy duty rubber of the tire hole has gradually worsened and rocks, sticks and such have gotten in puncturing the inner tube so we had a slow leak that mean parking the tractor near the compressor.
For a while we used green slime. A gallon of it in the tire kept us going for another year. It really does work, on a slow vehicle like this, but it doesn’t last forever. So on a bright, warm, dry spring day Will and I tackled the tire.
Internal Tire Patch
Will took the tire half way off, unseating one bead from the rim, and removed the old inner tube. He cut it up and cleaned off a section to make patches for the outer tire. Using rubber cement we patched the outer tire with not one, not two but three patches, each larger than the other. The first one covered the hole and a bit. Each larger patch provided more coverage. This is to keep sticks and rocks from coming in to puncture the new inner tube.
It is just like patching a bicycle tire, except that the tire weighs more than any bicycle and on a bike you put the patch on the inner tube while we put it on the hard outer tire. The trick with the rubber cement is to apply it liberally (this is not about politics) to the face of the patch and then rub the patch over the area it will go on, smearing it around about an inch beyond. Then take the patch off and let the rubber cement cure. Once it is tacky we pressed the tacky patch to the tacky tire and they locked together with a bit of rubbing.
Insert the new inner tube, align the stem, inflate it a little bit and reseat the tire bead on the inner rim. Well, it was a bit harder than that but the bead was finally on using the long handled spoons.
Next by over inflating the tire it pops the bead out to the outer rim of the tire, in theory. Will finally realized our chains were holding it back. Deflate, release the chains, re-inflate, still no joy for the last bit. The bead was staying down in the inner rim. We applied some grease to the rim and the bead. Re-inflate and it snapped into position.
With the tire a little over inflated to open the cracks I painted on two part polyurea. This is the same tough material I’m using in the floors, walls and ceilings of our butcher shop to seal the concrete. The idea is to seal up the crack in the tire which has been letting stones and stick in to puncture the inner tube. The polyurea is the black painted on material that is shown in the top picture.
Once I had the cracks deeply filled we returned the tire to its standard working pressure of 18 psi and the cracks closed up, sealing in the polyurea. We left it like that for 48 hours to cure fully. After two days the polyurea felt about as hard as the rubber, maybe slightly harder, and was firmly bonded to the tire.
It’s only been a couple of weeks but so far so good. Maybe this is a new use for polyurea and a new way to repair tires, at least on slow moving vehicles.
One of the nice things about tractors is they can jack themselves up when you have to change a tire or do other work. Very handy.
Update 20160412: Someone asked how the tire is doing after two years and for the source of the polyurea… It is holding up well. Dynasolve.com was the source of the polyurea. That saved a ~$800 tire letting it last years longer. That was the price years ago so it may have gone up by now.
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