tok-tokkie
Race Dog
I had trouble with a patch coming off the tube I had repaired on a trip through the Karoo recently. I have read of others (Michnus for example) having the same problem; the speculation is that there is silicon in the rubber so the patch just comes off after a few kilometres. Mine had stuck for 69 kilometres. I had a spare tube which I fitted but that too got a puncture so I had to fit the previously repaired one.
That is the one where the patch came off (I have pulled it right off because I wanted to see what it looked like underneath – it was loose from the hole up in the 1 o/clock direction only).
I was a tyre retreader as my first career for 10 years. I have done the training course at the Rema Tip-Top factory in Munich on both their tube & tyre repair products and also conveyor belt splicing (seem to have lost the certificate). I thought I would do some tests when I got home to show what the problems are, what products are best, what the difference between the tubes are give some good advice. I have now done all that and – I have nothing conclusive to report at all.
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I had two tubes: Bridgestone (Japan) & Cheng Shong (?) (Taiwan)
Two patch makes: Yong Cheng (China) & Rema Tip-Top (Germany)
So I would fit each make of patch on each make of tube and see which worked best. I was quite sure that a German patch on a Japanese tube would work much better than a Chinese patch on a Taiwanese tube. In fact I could come to no conclusion from my tests.
I have been trying to make a pendulum clock on & off for years. To make the pendulum bob I made a rig where i clamped a circle of 1mm brass in it and inflated it with a panel beaters hydraulic pump.
That is the bob, silver soldered together, polished, nickel plated and filled with lead.
That is a Tip-Top patch on the Cheng Shong tube in the test rig.
That is the Tip-Top patch sticking perfectly to the Cheng Shong tube when it has been well inflated.
Side view of Bridgestone tube with Yong Cheng patch (CH=Chinese); not fully inflated yet.
Top view of Bridgestone tube and Yong Cheng patch. The white circular patch in the center is the hole I punched in the tube before patching it.
So that proved nothing. Being a scatter-brained old fool I stuck both the same patches on the same tubes.
I had prepared those tubes properly using my Proxxon (German Dremel type tool) with a 80 grit flap wheel and finished the buffing with 80 grit emery cloth. I decided to repeat the test but not use the Proxxon to see how well I could repair a tube on the roadside. I used the little metal rasp that came in the Yong Cheng kit and also a small 80 grit sanding drum but holding it in my hand. I had thought about it and decided that I could easily take that with me on trips and be sure of properly roughing (& cleaning) the tube before sticking the patch. I wanted to see that the patch stuck just as well when not using the Proxxon.
That is done just by hand. You can see some scratches from the metal rasp. I have completely sanded the ridge away where the patch will fit. I have got rid of all the smooth grey surface of the tube to expose fresh clean rubber. When buffing the tube I did it on my knee & always moved the rasp away from the hole so the surface skin material was always moved away from where the patch was going to be stuck – I turned the tube as I did the buffing. After using the metal rasp I used the sanding band fitted to the arbour. That makes it much easier to use than just a piece of emery cloth. I sanded the whole area as you see. The sanding band does a much more thorough job than the metal rasp. I will take it with me whenever i go on a trip.
A close up of the sanding bands.
I then put a good quantity of the solution on the buffed area and rubbed it in with a ‘clean’ finger so the solution was properly worked into the roughened surface. I carried on for a few seconds but stopped as soon as the solution stared to get tacky as the toluene evaporated. I then set my phone to count down for 10 minutes to allow the solution to properly dry ready for the patch. Bend the patch to make the tin foil split across the middle of the patch and peel the foil half off each side so you can hold the patch in a nice curve without touching the sticky side and center it over the hole & put it in place. Then pull out the tin foil and roll the patch onto the tube using the back of a screwdriver handle. Work from the center outwards. Press quite firmly on the screwdriver to really force the patch into contact with the solution on the tube. I then left the tube overnight before doing the test (as i also did for the first ones). A chemical reaction has to take place between the solution and the sticky side of the patch so giving it time ensures that reaction can go all the way. When I got the first puncture I had to spend the night at the roadside near Verneukpan – I repaired the old tube before I started riding the next day so that the patch would have plenty of time for the chemical curing process to complete before I used the tube again (which happened to be after lunch that same day).
Cheng Shong tube with Yong Cheng patch after hand buffing only.
Bridgestone tube with Tip-Top patch after hand buffing only.
Well now I had done the other combination of patches and tubes and, even without using a power tool, they both seemed to be sticking perfectly. (This patch is bigger than the previous Tip-Top one)
There was one other test I could do. The Cheng Shong tube had a patch that I had fitted by the roadside. I only had the metal rasp with me (no 80 grit sanding band) when I fitted that patch. I was very dubious about that patch when I fitted it – I tried to peel the cellophane off the top of the patch after fitting it & it looked like the patch was being pulled off so I left it (I also did not pull it off the Yong Cheng patches i fitted for this test for the same reason; as i inflated the tube the cellophane came loose & I have taken it off before taking the photos. I had that tube with me so put it in the test rig.
Chong Sheng tube with Yong Cheng patch fitted by the roadside.
Same roadside repair well inflated. I don’t think the dark spot is the puncture – it was just a thorn prick and should be close to the center of the patch.
This tube did pop. Notice that it did not tear through the mystery black spot. I am not surprised that this popped. I had used a 5mm punch to make the test holes so there was no tear in the tube; a tear concentrates the forces and makes it much easier to tear the tube further.
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So this testing method shows no problem with fixing a tube yet we know that there are problems. Static inflation like I have done is different to the deflection that takes place when the tyre rolls across the ground. Even so, I find those tests pretty impressive. Just they can’t be believed.
That is the one where the patch came off (I have pulled it right off because I wanted to see what it looked like underneath – it was loose from the hole up in the 1 o/clock direction only).
I was a tyre retreader as my first career for 10 years. I have done the training course at the Rema Tip-Top factory in Munich on both their tube & tyre repair products and also conveyor belt splicing (seem to have lost the certificate). I thought I would do some tests when I got home to show what the problems are, what products are best, what the difference between the tubes are give some good advice. I have now done all that and – I have nothing conclusive to report at all.
---------------------------------------------------------------------------------------------------------
I had two tubes: Bridgestone (Japan) & Cheng Shong (?) (Taiwan)
Two patch makes: Yong Cheng (China) & Rema Tip-Top (Germany)
So I would fit each make of patch on each make of tube and see which worked best. I was quite sure that a German patch on a Japanese tube would work much better than a Chinese patch on a Taiwanese tube. In fact I could come to no conclusion from my tests.
I have been trying to make a pendulum clock on & off for years. To make the pendulum bob I made a rig where i clamped a circle of 1mm brass in it and inflated it with a panel beaters hydraulic pump.
That is the bob, silver soldered together, polished, nickel plated and filled with lead.
That is a Tip-Top patch on the Cheng Shong tube in the test rig.
That is the Tip-Top patch sticking perfectly to the Cheng Shong tube when it has been well inflated.
Side view of Bridgestone tube with Yong Cheng patch (CH=Chinese); not fully inflated yet.
Top view of Bridgestone tube and Yong Cheng patch. The white circular patch in the center is the hole I punched in the tube before patching it.
So that proved nothing. Being a scatter-brained old fool I stuck both the same patches on the same tubes.
I had prepared those tubes properly using my Proxxon (German Dremel type tool) with a 80 grit flap wheel and finished the buffing with 80 grit emery cloth. I decided to repeat the test but not use the Proxxon to see how well I could repair a tube on the roadside. I used the little metal rasp that came in the Yong Cheng kit and also a small 80 grit sanding drum but holding it in my hand. I had thought about it and decided that I could easily take that with me on trips and be sure of properly roughing (& cleaning) the tube before sticking the patch. I wanted to see that the patch stuck just as well when not using the Proxxon.
That is done just by hand. You can see some scratches from the metal rasp. I have completely sanded the ridge away where the patch will fit. I have got rid of all the smooth grey surface of the tube to expose fresh clean rubber. When buffing the tube I did it on my knee & always moved the rasp away from the hole so the surface skin material was always moved away from where the patch was going to be stuck – I turned the tube as I did the buffing. After using the metal rasp I used the sanding band fitted to the arbour. That makes it much easier to use than just a piece of emery cloth. I sanded the whole area as you see. The sanding band does a much more thorough job than the metal rasp. I will take it with me whenever i go on a trip.
A close up of the sanding bands.
I then put a good quantity of the solution on the buffed area and rubbed it in with a ‘clean’ finger so the solution was properly worked into the roughened surface. I carried on for a few seconds but stopped as soon as the solution stared to get tacky as the toluene evaporated. I then set my phone to count down for 10 minutes to allow the solution to properly dry ready for the patch. Bend the patch to make the tin foil split across the middle of the patch and peel the foil half off each side so you can hold the patch in a nice curve without touching the sticky side and center it over the hole & put it in place. Then pull out the tin foil and roll the patch onto the tube using the back of a screwdriver handle. Work from the center outwards. Press quite firmly on the screwdriver to really force the patch into contact with the solution on the tube. I then left the tube overnight before doing the test (as i also did for the first ones). A chemical reaction has to take place between the solution and the sticky side of the patch so giving it time ensures that reaction can go all the way. When I got the first puncture I had to spend the night at the roadside near Verneukpan – I repaired the old tube before I started riding the next day so that the patch would have plenty of time for the chemical curing process to complete before I used the tube again (which happened to be after lunch that same day).
Cheng Shong tube with Yong Cheng patch after hand buffing only.
Bridgestone tube with Tip-Top patch after hand buffing only.
Well now I had done the other combination of patches and tubes and, even without using a power tool, they both seemed to be sticking perfectly. (This patch is bigger than the previous Tip-Top one)
There was one other test I could do. The Cheng Shong tube had a patch that I had fitted by the roadside. I only had the metal rasp with me (no 80 grit sanding band) when I fitted that patch. I was very dubious about that patch when I fitted it – I tried to peel the cellophane off the top of the patch after fitting it & it looked like the patch was being pulled off so I left it (I also did not pull it off the Yong Cheng patches i fitted for this test for the same reason; as i inflated the tube the cellophane came loose & I have taken it off before taking the photos. I had that tube with me so put it in the test rig.
Chong Sheng tube with Yong Cheng patch fitted by the roadside.
Same roadside repair well inflated. I don’t think the dark spot is the puncture – it was just a thorn prick and should be close to the center of the patch.
This tube did pop. Notice that it did not tear through the mystery black spot. I am not surprised that this popped. I had used a 5mm punch to make the test holes so there was no tear in the tube; a tear concentrates the forces and makes it much easier to tear the tube further.
----------------------------------------------------------------------------------------------------------------------
So this testing method shows no problem with fixing a tube yet we know that there are problems. Static inflation like I have done is different to the deflection that takes place when the tyre rolls across the ground. Even so, I find those tests pretty impressive. Just they can’t be believed.
