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#41
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Elmer's Rubber Cement is not the vulcanizing kind!
On 27 Apr, 04:08, (Tom Keats) wrote:
In article , * * * * Ablang writes: I bought a 4oz jar (UPC 0 269050 8) of this stuff from Home Depot last year for about $2.50. *Pretty cheap stuff. I finally got a chance to use these on my inner tubes for my 27" x 1-1/4" tires (100 psi) and found out that they don't really stick permanently. *The next day I discover that some part of the patch has breached. In trying to figure out what I did wrong (I have successfully patched other tires before using the glue from patch kits), I figure it's that I'm either using too thick of a layer of Elmer's or that this rubber cement really isn't the vulcanizing kind. What do you guys think? Where can I buy (in bulk) a large amount of the vulcanizing cement from at the best price? Y'see what a Pandora's can o' worms you've opened? * ;-) *;-) *;-) Might as well have started another chain cleaning/lubrication thread. Might have already happened. |
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#42
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Elmer's Rubber Cement is not the vulcanizing kind!
In article ,
jim beam writes: Martin Riddle wrote: "Tom Keats" wrote in message ... In article , Tom Sherman writes: Ablang ? wrote: I bought a 4oz jar (UPC 0 269050 8) of this stuff from Home Depot last year for about $2.50. Pretty cheap stuff. I finally got a chance to use these on my inner tubes for my 27" x 1-1/4" tires (100 psi) and found out that they don't really stick permanently. The next day I discover that some part of the patch has breached. In trying to figure out what I did wrong (I have successfully patched other tires before using the glue from patch kits), I figure it's that I'm either using too thick of a layer of Elmer's or that this rubber cement really isn't the vulcanizing kind. What do you guys think? Where can I buy (in bulk) a large amount of the vulcanizing cement from at the best price? I was under the impression that vulcanizing requires heat and a curative to produce cross-linking of the polymers, and "vulcanizing fluid" is a marketing term. As I understand it, so-called "vulcanizing" rubber cement chemically integrates with the existing rubber to which it is applied. This effect should be desirable with regard to tire repairs, since holes in tires are external and thereby exposed to all kinds of stresses and tensions. I've long been under the impression that patch kit cement is of the vulcanizing kind, but upon further research I'm prepared to admit to error on my part. If patch kit rubber cement truly is non-vulcanizing, it nevertheless works for inner tube patches when it's properly applied, the layers of cement are allowed to set ("cure") for a few minutes before applying patch to hole, and the patched tube is rested overnight before inflating. I suspect the reason for letting the cement dry for a few minutes before sticking the patch on, is to let it become more viscous so that Surface Tension pulls (pushes?) the patch more firmly into place against the tube. I think the "good" rubber cement for tube patching has a solvent in it, like acetone or some kind of pentane or other volatile solvent who's job is to keep it storable & fluid enough to spread it, and that's the solvent's only purpose. Once the cement is applied, the next step is to let that solvent evaporate so the remaining cement can do it's job. I might be wrong about that, too -- I'm just guessing. Maybe Jobst will set us all straight. Maybe it's better to patch inner tubes during a rainy day, when the air pressure is higher? Surface tension, 'n all that. cheers, Tom I just looked at a jar of Elmer's Rubber cement and it contains N-Heptane. As opposed to the tube of cement I have from Aid Auto, that has Heptane. Which by chance is also known as N-Heptane. I doubt that rubber cement actually has different flavors, but in this context of repairing a inner tube, it�s the same. There no such thing as cold vulcanization, room temperature yes, but its RTV. http://en.wikipedia.org/wiki/Vulcanization If you want to Vulcanize a patch you need the vulcanizing hot patch kit and watch the flames. (which is kinda fun) Here's an example http://www.advrider.com/forums/showthread.php?t=419095 The Allmighty EPA in the US has banned these, so us Americans are out of luck. Even the Park Vulcanizing patch kit is just rubber cement (heptane) and a patch with some orange polymer that sticks pretty good after turning to mush from the heptane. dude, heptane is just the solvent. doesn't mean **** about the bonding ingredients. There are no bonding ingredients. Sticking patches onto tubes is allegedly a non-chemical process, so there is thereby no bonding involved. Rubber cement is just gum with tiny fingers that somehow squirm around, feeling for molecular fingerholds into which to install themselves. Abracadabra. cheers, Tom -- Nothing is safe from me. I'm really at: tkeats curlicue vcn dot bc dot ca |
#43
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Elmer's Rubber Cement is not the vulcanizing kind!
Tom Keats wrote:
In article , jim beam writes: Martin Riddle wrote: "Tom Keats" wrote in message ... In article , Tom Sherman writes: Ablang ? wrote: I bought a 4oz jar (UPC 0 269050 8) of this stuff from Home Depot last year for about $2.50. Pretty cheap stuff. I finally got a chance to use these on my inner tubes for my 27" x 1-1/4" tires (100 psi) and found out that they don't really stick permanently. The next day I discover that some part of the patch has breached. In trying to figure out what I did wrong (I have successfully patched other tires before using the glue from patch kits), I figure it's that I'm either using too thick of a layer of Elmer's or that this rubber cement really isn't the vulcanizing kind. What do you guys think? Where can I buy (in bulk) a large amount of the vulcanizing cement from at the best price? I was under the impression that vulcanizing requires heat and a curative to produce cross-linking of the polymers, and "vulcanizing fluid" is a marketing term. As I understand it, so-called "vulcanizing" rubber cement chemically integrates with the existing rubber to which it is applied. This effect should be desirable with regard to tire repairs, since holes in tires are external and thereby exposed to all kinds of stresses and tensions. I've long been under the impression that patch kit cement is of the vulcanizing kind, but upon further research I'm prepared to admit to error on my part. If patch kit rubber cement truly is non-vulcanizing, it nevertheless works for inner tube patches when it's properly applied, the layers of cement are allowed to set ("cure") for a few minutes before applying patch to hole, and the patched tube is rested overnight before inflating. I suspect the reason for letting the cement dry for a few minutes before sticking the patch on, is to let it become more viscous so that Surface Tension pulls (pushes?) the patch more firmly into place against the tube. I think the "good" rubber cement for tube patching has a solvent in it, like acetone or some kind of pentane or other volatile solvent who's job is to keep it storable & fluid enough to spread it, and that's the solvent's only purpose. Once the cement is applied, the next step is to let that solvent evaporate so the remaining cement can do it's job. I might be wrong about that, too -- I'm just guessing. Maybe Jobst will set us all straight. Maybe it's better to patch inner tubes during a rainy day, when the air pressure is higher? Surface tension, 'n all that. cheers, Tom I just looked at a jar of Elmer's Rubber cement and it contains N-Heptane. As opposed to the tube of cement I have from Aid Auto, that has Heptane. Which by chance is also known as N-Heptane. I doubt that rubber cement actually has different flavors, but in this context of repairing a inner tube, it�s the same. There no such thing as cold vulcanization, room temperature yes, but its RTV. http://en.wikipedia.org/wiki/Vulcanization If you want to Vulcanize a patch you need the vulcanizing hot patch kit and watch the flames. (which is kinda fun) Here's an example http://www.advrider.com/forums/showthread.php?t=419095 The Allmighty EPA in the US has banned these, so us Americans are out of luck. Even the Park Vulcanizing patch kit is just rubber cement (heptane) and a patch with some orange polymer that sticks pretty good after turning to mush from the heptane. dude, heptane is just the solvent. doesn't mean **** about the bonding ingredients. There are no bonding ingredients. Sticking patches onto tubes is allegedly a non-chemical process, so there is thereby no bonding involved. Rubber cement is just gum with tiny fingers that somehow squirm around, feeling for molecular fingerholds into which to install themselves. Abracadabra. cheers, Tom ok, you can't read. 'nuff said. |
#44
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Elmer's Rubber Cement is not the vulcanizing kind!
On Apr 26, 6:55*pm, wrote:
Michael Press wrote: Remove a well adhered patch. *You will see no indication of chemical bond formation. I find a well adhered patch not removable without heating. *Heating affects the REMA patch orange rubber more than the tube rubber so they separate with careful pulling. *I have not cared what remains on the contact surface (it looks clean to me) before applying a new patch and allowing it to cure. I have also removed quite a few patches using a suitable solvent - toluene and xylene are two that work. The hard part seems to be getting a patch edge lifted to gain acces to the tube/patch interface. Once that is accomplished the rest is easy using a slow "peeling" technique in conjunction with more solvent (think "cotton swab"). Even well adhered patches will come off clean leaving no sign that there was ever a patch adhered/bonded there. Everyone seems to agree on that last detail. DR |
#45
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Elmer's Rubber Cement is not the vulcanizing kind!
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#46
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Elmer's Rubber Cement is not the vulcanizing kind!
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#47
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Elmer's Rubber Cement is not the vulcanizing kind!
Still Just Me wrote:
On Sun, 26 Apr 2009 07:45:56 -0700, jim beam wrote: What's a suggested glue for tube on tube patching? are you for real? how can you read a post that just tells you mechanism and application, yet still utterly fail to comprehend what it means? [rhetorical] I'm looking for a brand name or two, Mr. personality, not a chemical composition. Perhaps if your primary mission wasn't to be the biggest asshole on the Usenet, you might have detected that. "hello, is this the psychic hotline? can you tell me what sjm actually wants please? 'cos he's apparently incapable of stating anything so simple. thanks for your help" that's $2.99 per minute to you buddy. |
#49
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Elmer's Rubber Cement is not the vulcanizing kind!
In article ,
Phil W Lee phil(at)lee-family(dot)me(dot)uk writes: We're being told one substance somehow molecularly intimates and intermingles itself with another similar substance, and yet the process is not chemical. Think of velcro, then reduce in scale to the molecular level. The preparation with rubber cement can be visualised as the process which makes the fibres on one side curl up into little hooks. Aaah, I can visualize that. Thank you. cheers, Tom -- Nothing is safe from me. I'm really at: tkeats curlicue vcn dot bc dot ca |
#50
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Elmer's Rubber Cement is not the vulcanizing kind!
Still Just Me wrote, On 4/27/2009 12:47 PM:
On Sun, 26 Apr 2009 21:08:16 -0700, jim beam wrote: tell us tom, how is it possible to read a perfectly well written post with the adhesion mechanism clearly explained, but still fail tot comprehend its contents. does it take practice? or do you have some special training? First you tell us why you don't capitalize properly. It's a multiple choice question. Possible answers: a. too lazy b. too stupid c. shift-key failure? -- Paul D Oosterhout I work for SAIC (but I don't speak for SAIC) |
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