Hot type Vulcanized tire repair info sought.

[corelokt]

I'd like to learn to do hot repairs to tires. For old bias ply type tires and farm equipment. Any chance one of you would happen to know some about this?

 

[hoplite666]

"Hot patches" are a thing of the past. Both the Tire Industry Association and the Rubber Manufacturers Association specifically say "hot patching" tires should not be done. All you're doing is burning away the vulcanizing cement which does the job of chemically bonding your patch to the tire.
That being said, back in the day before I knew any better, we would hot patch as follows:
Demount tire
Remove road debris or whatever punctured the tire
Ream out the hole with a carbide drill bit and a drill operating @ low rpm
Treat inner liner of the tire with rubber prep or buffing lube around the area to be patched/ plugged
Rake the area to remove the inner case liner ( kinda a waxy coating that helps keep air from permiating out)
Insert plug and trim flush with tire ( this is if using a 2 piece patch/plug)
Using buffing wheel buff inner case liner and plug until the rubber has a velvet like feel
Vacuum out all rubber dust from the drilling and buffing
Apply vulcanizing cement
.........this is when we would light the cement on fire....
After a few seconds blow out the flame
Apply patch
Use a roller to press the patch on
Coat the whole thing with repair sealant

 

[hoplite666]

These days we skip the part when you light the cement and instead let the cement sit for a few minutes and dry until it has a dull hazy appearance. Then apply the patch.
Key thing is to scrape away all the case liner and buff the tire down til its like velvet. Be careful not to go down too far and expose the belts. If you buff it down just right the vulcanizing cement does just that.....vulcanizes your patch to the tire. Its not glue. It chemically bonds the surfaces

 

[corelokt]

No No, I mean like putting rubber back in where rubber once was. Think holes, not punctures. Besides my tires don't take patch cement. I've tried buffing, sanding, scraping. Cleaning with brake cleaner, alcohol etc. The patch just peels off.
I've taken to patching the tube, and using pull through tire plug / patch combo with black rtv to seal the tire.
I want to be able to repair tractor tire side walls.

 

[hoplite666]

Any and all sidewall repairs I've done or seen done where total jerry rigs. Just enough to send someone limping down the road with no guarantee it was gonna hold. If there is a chunk out of a tire and the belts have become visible I wouldn't do anything but replace it. Have you seen a tire have a zipper rupture in the sidewall?
I have. The debris will literally tear off a limb....

I too have had trouble getting patches to stick. Usually only on riding mower or other small tires where you can't do much buffing. In those cases I just put a tube in them. As long as there is some meat left in the tread.
What's this for? If its not driven on the road or at speed and its just something you tool around on your property with then put a fresh tube in it. Even if its a "tubeless" tire.

 

[m16ty]

Actually, the hot patch process is where you buy these special patches with some kind of flammable stuff on one side of it and you use a specially made press that will fit the patch (all patches I've ever seen were diamond shaped). You put the patch on the tube, clamp it in the press, and set it on fire. When it cools off you're done and no vulcanizing cement is used. It's a old process that was used before they came out with vulcanizing cement.

I haven't seen any of these hot patches in years and don't even know if they are still available but the process worked really well. I also don't think you can use it for anything but tubes because I don't know how you'd get the press to work with a tire. I've still got a old patch press and would use it if I could find some hot patches.

I'm not sure that vulcanizing large sections of tires is something you can do at a home shop. I know that there is a place in Nashville that will do vulcanizing repairs on tires if the repair section isn't too big. I took them a tractor tire that had about a 6" cut in the sidewall and they said it was too big to fix.

 

[phil2968]

Actually, the hot patch process is where you buy these special patches with some kind of flammable stuff on one side of it and you use a specially made press that will fit the patch (all patches I've ever seen were diamond shaped). You put the patch on the tube, clamp it in the press, and set it on fire. ....

Yup, used those many times on my bicycle and mower tubes back in the 70's. Good lord I'm old!
It was a cardboard like stuff in metal that burnt slowly. It worked well.

 

[Keith_J]

Setting fire to cement is certainly bad, it isn't hot patching. In hot patching, the patch is vulcanized or changed from a gummy rubber to a cured, harder rubber. Think bubble gum for unvulcanized rubber.

Tire shops had electric patch heaters but self contained slow match type heaters were produced, these used potassium nitrate infused carbon or cotton in a metal iron to clamp the patch down to the tire/tube. The heater would have correct temperature time constant to properly vulcanize the patch.

modern chemistry has made these unnecessary, synthetic cements work just as well.