vulcanising solution goes off ?

[news.virgin.net]

Hi,
Does vulcanising solution go off like other adhesives ? If so whats the
usefull life of a) a sealed tube and b) an opened tube. With tyres getting
so good at preventing punctures today, I'm sure there are people who never
use their puncture kits and might find they fail when needed.

Thanks in advance,

Bruce.

[Ben C]

On 2007-11-20, jobst.brandt@stanfordalumni.org <jobst.brandt@stanfordalumni.org> wrote:
[...]
> That is how little practical understanding of tire patching anyone at
> REMA seems to have. They still believe patches are held best if the
> surface of the tube is "roughened". Many of my patch kits of the past
> had cheese graters for that purpose.

I always thought the cheese grater was for grating the French chalk.

After gluing the patch on you make some chalk powder and then spread it
around on top of the patch. I think the purpose is to neutralize any
excess glue and so stop the tube sticking to the inside of the outer
tyre.

[Chalo]

Jobst Brandt wrote:
>
> This reminds me of the REMA representative at InterBike in 2006 who
> was not aware that his patches take time to cure and that a fresh
> patch can be pulled off with ease while a day-old one cannot.
<snip>
> That is how little practical understanding of tire patching anyone at
> REMA seems to have. They still believe patches are held best if the
> surface of the tube is "roughened". Many of my patch kits of the past
> had cheese graters for that purpose. That's how bad things are in the
> business.

Maybe you'd get better immediate adhesion if you used a bit of
sandpaper (the new cheese grater) to rough up the patched area first.
In addition to increasing the surface area for the glue to act upon,
it also has the effect of breaking up and removing the coating of mold
release as well as leveling any seams or ribs on the tube surface.

I always sand the tube thoroughly enough to remove the waxy whitish
surface layer and leave only fresh black butyl for the glue to stick
to. I have no problems with patches lifting, even when they are
placed into service right after a repair.

Chalo

[cyclingthings@gmail.com]

On Nov 19, 4:40 am, "news.virgin.net" <a...@anon.net> wrote:
> Hi,
> Does vulcanising solution go off like other adhesives ? If so whats the
> usefull life of a) a sealed tube and b) an opened tube. With tyres getting
> so good at preventing punctures today, I'm sure there are people who never
> use their puncture kits and might find they fail when needed.
>
> Thanks in advance,
>
> Bruce.

for the super high pressures of today's tires , over 100 psi on road
tires, i would not use glue or any patching kits. you can get a whole
set of tubes on ebay for $20 a pack of 10
carlos
www.bikingthings.com
ride fast, get fit, live better, be happy

[Werehatrack]

On Mon, 19 Nov 2007 09:40:52 GMT, "news.virgin.net" <anon@anon.net>
may have said:

>Hi,
> Does vulcanising solution go off like other adhesives ? If so whats the
>usefull life of a) a sealed tube and b) an opened tube. With tyres getting
>so good at preventing punctures today, I'm sure there are people who never
>use their puncture kits and might find they fail when needed.

It doesn't usually decompose, it dries out. The small tubes are
particularly bad about this; the sealing crimp at the bottom of the
tube is sufficiently leaky that a patch kit which has lain unused in
the bottom of your spares bag (or on the store shelf) for a year will
often prove to have no useful adhesive in it when first opened.

I replace the tube of cement in my seat bag at the start and end of
summer whether I've used it up or not. The screw-top can I use at
home lasts for years.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

[Ozark Bicycle]

On Nov 19, 9:32 am, cyclingthi...@gmail.com wrote:
> On Nov 19, 4:40 am, "news.virgin.net" <a...@anon.net> wrote:
>
> > Hi,
> > Does vulcanising solution go off like other adhesives ? If so whats the
> > usefull life of a) a sealed tube and b) an opened tube. With tyres getting
> > so good at preventing punctures today, I'm sure there are people who never
> > use their puncture kits and might find they fail when needed.
>
> > Thanks in advance,
>
> > Bruce.
>
> for the super high pressures of today's tires , over 100 psi on road
> tires, i would not use glue or any patching kits.

Huh? Why not? Why toss a perfectly good tube when a patch does the
job. It's not just a money issue, it's a "why be wasteful?" issue,
too.


> you can get a whole
> set of tubes on ebay for $20 a pack of 10
> carloswww.bikingthings.com
> ride fast, get fit, live better, be happy

[carlfogel@comcast.net]

On Mon, 19 Nov 2007 07:32:28 -0800 (PST), cyclingthings@gmail.com
wrote:

>On Nov 19, 4:40 am, "news.virgin.net" <a...@anon.net> wrote:
>> Hi,
>> Does vulcanising solution go off like other adhesives ? If so whats the
>> usefull life of a) a sealed tube and b) an opened tube. With tyres getting
>> so good at preventing punctures today, I'm sure there are people who never
>> use their puncture kits and might find they fail when needed.
>>
>> Thanks in advance,
>>
>> Bruce.
>
>for the super high pressures of today's tires , over 100 psi on road
>tires, i would not use glue or any patching kits. you can get a whole
>set of tubes on ebay for $20 a pack of 10
>carlos
>www.bikingthings.com
>ride fast, get fit, live better, be happy

Dear Carlos,

Bicycle tire pressures are about what they've been for decades and
don't bother patches.

I've put over 200 Rema patches on three dozen Slime tubes, mostly for
goathead thorn punctures.

I'm down to two dozen tubes, twelve having been so badly damaged that
they couldn't be patched.

I run 110 psi, but used to run 125 psi.

I've had no patch problems and haven't heard of anyone on RBT with
patch problems.

Many bike shops do replace tubes because a new tube is faster and
cheaper than patching when the customer is waiting and you have to pay
an employee.

For someone who gets only occasional flats, a cheap new tube can make
sense for speed and convenience, but not for any improved
reliability--plenty of RBT posters patch without any problems.

In my case, 200 flats times $7 per mail-order Slime tube would have
been $1400, which would have been rather more expensive than $252 for
36 $7 Slime tubes plus about $30 for patches and glue.

Cheers,

Carl Fogel

[Pete Biggs]

> On Nov 19, 4:40 am, "news.virgin.net" <a...@anon.net> wrote:
>> Hi,
>> Does vulcanising solution go off like other adhesives ? If so
>> whats the usefull life of a) a sealed tube and b) an opened tube.
>> With tyres getting so good at preventing punctures today, I'm sure
>> there are people who never use their puncture kits and might find
>> they fail when needed.

It can dry up in the tube. One theory is that air gets in if the tube
wasn't crimped well.

It's not predicatable, so give your tube a squeeze every so often to test it
feels OK. If it's been opened, squeeze some solution out to see if it looks
OK.

Carry Park self-adhesive patches for backup.

cyclingthings@gmail.com wrote:
> for the super high pressures of today's tires , over 100 psi on road
> tires, i would not use glue or any patching kits. you can get a whole
> set of tubes on ebay for $20 a pack of 10

A properly patched inner tube will take 130 psi and more, no problem.

Anyway you should have a patch kit in addition to spare tube(s) for obvious
reasons.

~PB

[Artoi]

In article
<a5d530ab-5873-46b1-9a01-9996245327f3@i37g2000hsd.googlegroups.com>,
cyclingthings@gmail.com wrote:

> for the super high pressures of today's tires , over 100 psi on road
> tires, i would not use glue or any patching kits. you can get a whole
> set of tubes on ebay for $20 a pack of 10

May be cheap, but sure is bad for the environment.
--

[jobst.brandt@stanfordalumni.org]

Pete Biggs writes:

>>> Does vulcanising solution go off like other adhesives? If so
>>> whats the usefull life of a) a sealed tube and b) an opened tube.
>>> With tyres getting so good at preventing punctures today, I'm sure
>>> there are people who never use their puncture kits and might find
>>> they fail when needed.

> It can dry up in the tube. One theory is that air gets in if the
> tube wasn't crimped well.

Its volatile solvent (that allows the glue to dry when used)
evaporates through the crimped end, the warmer the faster.

> It's not predicatable, so give your tube a squeeze every so often to
> test it feels OK. If it's been opened, squeeze some solution out to
> see if it looks OK.

The accurate diagnostic is to open the cap, tube vertical, and see
whether solid or liquid emerges when squeezing the crimped end. If
liquid, carefully screw on cap with the liquid while still squeezing
the tube.

> Carry Park self-adhesive patches for backup.

....and belt and spenders!

>> for the super high pressures of today's tires, over 100 psi on road
>> tires, i would not use glue or any patching kits. you can get a
>> whole set of tubes on ebay for $20 a pack of 10

> A properly patched inner tube will take 130 psi and more, no problem.

There is no force on the patch that might make it fail, inflation
pressure being retained by the tire casing. Pressure has no part in
patch survival. However, a freshly patched tube is massaged in use by
biased ply tires allowing the tube to peel away from a fresh patch.

> Anyway you should have a patch kit in addition to spare tube(s) for
> obvious reasons.

http://www.sheldonbrown.com/brandt/patching.html

Jobst Brandt

[carlfogel@comcast.net]

On 19 Nov 2007 19:32:09 GMT, jobst.brandt@stanfordalumni.org wrote:

>Pete Biggs writes:
>
>>>> Does vulcanising solution go off like other adhesives? If so
>>>> whats the usefull life of a) a sealed tube and b) an opened tube.
>>>> With tyres getting so good at preventing punctures today, I'm sure
>>>> there are people who never use their puncture kits and might find
>>>> they fail when needed.
>
>> It can dry up in the tube. One theory is that air gets in if the
>> tube wasn't crimped well.
>
>Its volatile solvent (that allows the glue to dry when used)
>evaporates through the crimped end, the warmer the faster.
>
>> It's not predicatable, so give your tube a squeeze every so often to
>> test it feels OK. If it's been opened, squeeze some solution out to
>> see if it looks OK.
>
>The accurate diagnostic is to open the cap, tube vertical, and see
>whether solid or liquid emerges when squeezing the crimped end. If
>liquid, carefully screw on cap with the liquid while still squeezing
>the tube.
>
>> Carry Park self-adhesive patches for backup.
>
>...and belt and spenders!
>
>>> for the super high pressures of today's tires, over 100 psi on road
>>> tires, i would not use glue or any patching kits. you can get a
>>> whole set of tubes on ebay for $20 a pack of 10
>
>> A properly patched inner tube will take 130 psi and more, no problem.
>
>There is no force on the patch that might make it fail, inflation
>pressure being retained by the tire casing. Pressure has no part in
>patch survival. However, a freshly patched tube is massaged in use by
>biased ply tires allowing the tube to peel away from a fresh patch.
>
>> Anyway you should have a patch kit in addition to spare tube(s) for
>> obvious reasons.
>
>http://www.sheldonbrown.com/brandt/patching.html
>
>Jobst Brandt

Dear Bruce, Pete, and Jobst,

This kind of tube takes a long time to dry out:

http://i23.tinypic.com/x1x6ih.jpg

Eight ounces, genuine Rema, $9.95 plus shipping:


http://biketoolsetc.com/index.cgi?id=24393435553&d=single&c=Tire-Tube&sc=Repair-Kits-and-Supplies&tc=Cement&item_id=RE-203

Or you can stop by an auto store and pick up the same stuff for $5:


http://www.partsamerica.com/ProductDetail.aspx?MfrCode=VCT&MfrPartNumber=M8062&CategoryCode=3190

Cheers,

Carl Fogel

[jobst.brandt@stanfordalumni.org]

Where's the Hat-rack writes:

>> Does vulcanising solution go off like other adhesives? If so whats
>> the usefull life of a) a sealed tube and b) an opened tube. With
>> tyres getting so good at preventing punctures today, I'm sure there
>> are people who never use their puncture kits and might find they
>> fail when needed.

> It doesn't usually decompose, it dries out. The small tubes are
> particularly bad about this; the sealing crimp at the bottom of the
> tube is sufficiently leaky that a patch kit which has lain unused in
> the bottom of your spares bag (or on the store shelf) for a year
> will often prove to have no useful adhesive in it when first opened.
> I replace the tube of cement in my seat bag at the start and end of
> summer whether I've used it up or not. The screw-top can I use at
> home lasts for years.

You might think that REMA and others would discover that highly
volatile solutions don't survive reliably in mechanically crimped
"toothpaste" tubes, their solvents being highly volatile by design.
This reminds me of the REMA representative at InterBike in 2006 who
was not aware that his patches take time to cure and that a fresh
patch can be pulled off with ease while a day-old one cannot.

To show how good his patches are, he installed one on a sample tube he
had at hand, allowing the rubber solution to dry before placing the
red-rimmed patch and rolling it down with a roller. Then he handed it
to me for inspection and I pulled it off effortlessly.

That is how little practical understanding of tire patching anyone at
REMA seems to have. They still believe patches are held best if the
surface of the tube is "roughened". Many of my patch kits of the past
had cheese graters for that purpose. That's how bad things are in the
business. Well installed, day-old cured patches cannot be readily
removed in one piece without heat.

http://www.sheldonbrown.com/brandt/patching.html

Jobst Brandt

[vey]

jobst.brandt@stanfordalumni.org wrote:
Well installed, day-old cured patches cannot be readily
> removed in one piece without heat.
>
> http://www.sheldonbrown.com/brandt/patching.html

What I have started doing is keeping a spare tube. When I get a flat, I
toss that tube in there and patch the other under controlled conditions
at home. That way, the patch gets more than a full day to cure before
the tube is needed and the patched tube becomes the spare.

[vey]

jobst.brandt@stanfordalumni.org wrote:

> That is how little practical understanding of tire patching anyone at
> REMA seems to have.

Is this something unique to REMA patches? Or maybe it is because of the
switch to butyl inner tubes? In the '60's and 70's, I do not remember
having as much trouble patching tires as I do now. My trouble with
patches began in the '80's, I think. I assumed it was my fault for being
sloppy.

I use REMA now, but before the '80's I used a different American (had a
spinning top?) brand that came with a much bigger tube of glue and
required cutting out a patch to fit. It also came with a little cheese
grater as you describe and there was no cellophane on the patch. It did
require peeling away the one side of the patch.

I remember patching being a simple matter and being underway again in 20
minutes. Now, I worry about patches leaking if I ride again right away
or if I accidentally peel the patch off while trying to remove the
cellophane.

In the early 90's I owned a commercial truck that had tubed tires and
split rims. I couldn't patch the tube myself because I didn't have the
tools to remove the tire, but I was allowed in the back to watch the
process.

I don't remember patching the truck tire being a big problem. The tube
was butyl, I think, because it had a blue stripe. The tire guys would
apply the glue and literally slap a patch on there, hold it for about 10
seconds and remount the tire. They didn't even wait for the glue to dry
before they slapped the patch on there. Some fellows lit the glue on
fire before they slapped the patch on there. In and out in 20 minutes.
That was the rule. They didn't have time for fiddling.

So why this has become a problem after years and years of no trouble?
Are truck inner tubes so different than bicycle inner tubes?
What doesn't REMA "get" that the older American company did?

[still just me]

On Tue, 20 Nov 2007 02:27:54 -0600, Ben C <spamspam@spam.eggs> wrote:

>
>I always thought the cheese grater was for grating the French chalk.
>
>After gluing the patch on you make some chalk powder and then spread it
>around on top of the patch. I think the purpose is to neutralize any
>excess glue and so stop the tube sticking to the inside of the outer
>tyre.

But these days it would be caulk from Thailand.

[Peter Cole]

Ben C wrote:
> On 2007-11-20, jobst.brandt@stanfordalumni.org <jobst.brandt@stanfordalumni.org> wrote:
> [...]
>> That is how little practical understanding of tire patching anyone at
>> REMA seems to have. They still believe patches are held best if the
>> surface of the tube is "roughened". Many of my patch kits of the past
>> had cheese graters for that purpose.
>
> I always thought the cheese grater was for grating the French chalk.
>
> After gluing the patch on you make some chalk powder and then spread it
> around on top of the patch. I think the purpose is to neutralize any
> excess glue and so stop the tube sticking to the inside of the outer
> tyre.

I've never had a patch stick to the inside of a tire, even when I tried
to deliberately glue it on.

[Ozark Bicycle]

On Nov 20, 7:42 am, vey <jun...@ericvey.com> wrote:
> jobst.bra...@stanfordalumni.org wrote:
>
> Well installed, day-old cured patches cannot be readily
>
> > removed in one piece without heat.
>
> >http://www.sheldonbrown.com/brandt/patching.html
>
> What I have started doing is keeping a spare tube. When I get a flat, I
> toss that tube in there and patch the other under controlled conditions
> at home. That way, the patch gets more than a full day to cure before
> the tube is needed and the patched tube becomes the spare.

Yep, that's the sensible solution: carry a spare tube and patch the
puncture victim at home.

[Michael Press]

In article
<22ec0cee-447e-4504-a350-aa98da7d1ecf@l22g2000hsc.googl
egroups.com>,
Ozark Bicycle
<bicycleatelier@ozarkbicycleservice.com> wrote:

> On Nov 20, 7:42 am, vey <jun...@ericvey.com> wrote:
> > jobst.bra...@stanfordalumni.org wrote:
> >
> > Well installed, day-old cured patches cannot be readily
> >
> > > removed in one piece without heat.
> >
> > >http://www.sheldonbrown.com/brandt/patching.html
> >
> > What I have started doing is keeping a spare tube. When I get a flat, I
> > toss that tube in there and patch the other under controlled conditions
> > at home. That way, the patch gets more than a full day to cure before
> > the tube is needed and the patched tube becomes the spare.
>
> Yep, that's the sensible solution: carry a spare tube and patch the
> puncture victim at home.

On rides out away from home I like to have three spare tubes.
* One to replace the punctured tube.
* One to replace the replacement tube that does not hold air.
* One for backup.

And a patch kit :)

--
Michael Press

[jobst.brandt@stanfordalumni.org]

Peter Cole writes:

>>> That is how little practical understanding of tire patching anyone
>>> at REMA seems to have. They still believe patches are held best
>>> if the surface of the tube is "roughened". Many of my patch kits
>>> of the past had cheese graters for that purpose.

>> I always thought the cheese grater was for grating the French chalk.

>> After gluing the patch on you make some chalk powder and then
>> spread it around on top of the patch. I think the purpose is to
>> neutralize any excess glue and so stop the tube sticking to the
>> inside of the outer tyre.

> I've never had a patch stick to the inside of a tire, even when I
> tried to deliberately glue it on.

I've never had a butyl tube not stick to the tire casing if it was in
there for more than 100 miles, and why should I care. A stuck tube
doesn't go flat a suddenly as a loose one, the tire casing then being
the local leak that is plugged by the piece of glass or thorn. The
tube must be pulled from the tire with a little force but that isn't a
drawback.

Jobst Brandt

[Ben C]

On 2007-11-20, Peter Cole <peter_cole@comcast.net> wrote:
> Ben C wrote:
>> On 2007-11-20, jobst.brandt@stanfordalumni.org <jobst.brandt@stanfordalumni.org> wrote:
>> [...]
>>> That is how little practical understanding of tire patching anyone at
>>> REMA seems to have. They still believe patches are held best if the
>>> surface of the tube is "roughened". Many of my patch kits of the past
>>> had cheese graters for that purpose.
>>
>> I always thought the cheese grater was for grating the French chalk.
>>
>> After gluing the patch on you make some chalk powder and then spread it
>> around on top of the patch. I think the purpose is to neutralize any
>> excess glue and so stop the tube sticking to the inside of the outer
>> tyre.
>
> I've never had a patch stick to the inside of a tire, even when I tried
> to deliberately glue it on.

I've had them stick a little bit, but not so you couldn't just pull them
apart fairly easily and without damaging anything.

Not all puncture repair kits come with the chalk anyway. I don't think
it's necessary.

[Ozark Bicycle]

On Nov 20, 3:15 pm, Michael Press <rub...@pacbell.net> wrote:
> In article
> <22ec0cee-447e-4504-a350-aa98da7d1...@l22g2000hsc.googl
> egroups.com>,
> Ozark Bicycle
>
>
>
> <bicycleatel...@ozarkbicycleservice.com> wrote:
> > On Nov 20, 7:42 am, vey <jun...@ericvey.com> wrote:
> > > jobst.bra...@stanfordalumni.org wrote:
>
> > > Well installed, day-old cured patches cannot be readily
>
> > > > removed in one piece without heat.
>
> > > >http://www.sheldonbrown.com/brandt/patching.html
>
> > > What I have started doing is keeping a spare tube. When I get a flat, I
> > > toss that tube in there and patch the other under controlled conditions
> > > at home. That way, the patch gets more than a full day to cure before
> > > the tube is needed and the patched tube becomes the spare.
>
> > Yep, that's the sensible solution: carry a spare tube and patch the
> > puncture victim at home.
>
> On rides out away from home I like to have three spare tubes.
> * One to replace the punctured tube.
> * One to replace the replacement tube that does not hold air.
> * One for backup.
>
> And a patch kit :)
>

The belt, belt, belt and suspenders approach! ;-)

I'm lucky in that I very rarely (prior to this August, my last flat
was in May or June '05) get flats, so a single tube seems to serve me
quite well. I have taken to carrying some glueless patches (duck!) to
help those poor souls who flat and have neither tube nor patch. I
carry an extra CO2 cartridge for the same reason.

[jobst.brandt@stanfordalumni.org]

someone snipes anonymously:

>> That is how little practical understanding of tire patching anyone
>> at REMA seems to have.

> Is this something unique to REMA patches? Or maybe it is because of
> the switch to butyl inner tubes? In the '60's and 70's, I do not
> remember having as much trouble patching tires as I do now. My
> trouble with patches began in the '80's, I think. I assumed it was
> my fault for being sloppy.

This is an old story and probably long ago when these rubber solutions
were developed and tire patching was new, chemists who understood the
means by which patches could be made to adhere reliably. The state of
the art is elsewhere today and the formulas are fixed for the various
products. It's up to the user to make the best of what the market
offers.

> I use REMA now, but before the '80's I used a different American (had a
> spinning top?) brand that came with a much bigger tube of glue and
> required cutting out a patch to fit. It also came with a little cheese
> grater as you describe and there was no cellophane on the patch. It did
> require peeling away the one side of the patch.

The size of the glue tube is not the problem but rather how well it is
crimped at the end from which it is filled. New tubes of glue are
made in a mold such that the exit neck has no opening. These tubes
are filled from the "bottom" and then crimped shut.

> I remember patching being a simple matter and being underway again
> in 20 minutes. Now, I worry about patches leaking if I ride again
> right away or if I accidentally peel the patch off while trying to
> remove the cellophane.

You may have recalled it that way, but I'm sure I was patching tires
before you rode a bicycle and discovered that a fresh patch is not
reliable. By observing my tire tubes and those of others I noted that
most patches, ridden when fresh, on inspection by dissection showed
that they had lifted... your's included no doubt. Not that they all
leaked, but those that did were in contact only near their edges.

> In the early 90's I owned a commercial truck that had tubed tires
> and split rims. I couldn't patch the tube myself because I didn't
> have the tools to remove the tire, but I was allowed in the back to
> watch the process.

> I don't remember patching the truck tire being a big problem. The
> tube was butyl, I think, because it had a blue stripe. The tire
> guys would apply the glue and literally slap a patch on there, hold
> it for about 10 seconds and remount the tire. They didn't even wait
> for the glue to dry before they slapped the patch on there. Some
> fellows lit the glue on fire before they slapped the patch on there.
> In and out in 20 minutes. That was the rule. They didn't have time
> for fiddling.

The amount of stretch in a bicycle tube to fill the volume of a tire
casing is far greater than that of car and truck tires of old. Tube
separation from a patch is fairly universal with patches on bicycle
tubes that are ridden immediately after application. The truck tire
tube does not stretch sufficiently to cause separation.

I hope you can visualize that when expanded to fill the tire, the
patch is held firmly against the casing while the tube at the hole can
pull away, air pressure entering into the tiny annular gap around the
perforation.

> So why this has become a problem after years and years of no
> trouble? Are truck inner tubes so different than bicycle inner
> tubes? What doesn't REMA "get" that the older American company did?

It has always been troublesome but few folks rode long distances and
even fewer rode such distances on fresh patches. Among my bikie
friends is where I first encountered these problems in the 1950's.

Jobst Brandt

[dustoyevsky@mac.com]

On Nov 20, 6:51 pm, vey <jun...@ericvey.com> wrote:

> Is this something unique to REMA patches? Or maybe it is because of the
> switch to butyl inner tubes? In the '60's and 70's, I do not remember
> having as much trouble patching tires as I do now. My trouble with
> patches began in the '80's, I think. I assumed it was my fault for being
> sloppy.

(solvent-free 'lectronic pasting):

http://www.epa.gov/safewater/contaminants/pdfs/contam_timeline.pdf

"Regulated" (whatever that might mean) by the EPA-- benzene in '87,
toluene in '91.

Somewhere is info on if/when "they" changed the formulation of
"airplane glue"-- and presumably vulcanizing fluid.

I emailed Testors. More later. --D-y

[Tom Sherman]

jobst.brandt@stanfordalumni.org aka Jobst Brandt wrote:
> someone snipes anonymously:

"Someone" = Eric Vey?

--
Tom Sherman - Holstein-Friesland Bovinia
"the grinning buddy bear carries a fork." - g.d.

[dustoyevsky@mac.com]

On Nov 20, 11:06 pm, jobst.bra...@stanfordalumni.org wrote:

(Vey posted):
> > I remember patching being a simple matter and being underway again
> > in 20 minutes. Now, I worry about patches leaking if I ride again
> > right away or if I accidentally peel the patch off while trying to
> > remove the cellophane.

(JB replied):

> You may have recalled it that way, but I'm sure I was patching tires
> before you rode a bicycle (interrupting)

1956 for me. I think Vey is a little older yet. Before that, it was a
tricycle, somewhat like this one:

http://dev1.boomersdomain.com/cgi-bin/store_pedalinghistory_2/00976.html

But of course by the time I came along they'd started using those
solid rubber tires-- the ones you don't have to patch. Rough as mine
rode, I'm glad I was born later. Must have been awful!

(continuing)

> and discovered that a fresh patch is not reliable. By observing my tire tubes and those of others I noted that
> most patches, ridden when fresh, on inspection by dissection showed
> that they had lifted... your's included no doubt. Not that they all
> leaked, but those that did were in contact only near their edges.

Generations since have followed in these observations (most without
having to acutally cut up the tube and patch to see where the air came
out), although some claim they can patch and ride immed., often with
the imputation that those who have different results were born
yesterday, so to speak.

(Vey continued his discourse thus):
> > In the early 90's I owned a commercial truck that had tubed tires
> > and split rims. I couldn't patch the tube myself because I didn't
> > have the tools to remove the tire, but I was allowed in the back to
> > watch the process.
> > I don't remember patching the truck tire being a big problem. The
> > tube was butyl, I think, because it had a blue stripe. The tire
> > guys would apply the glue and literally slap a patch on there, hold
> > it for about 10 seconds and remount the tire. They didn't even wait
> > for the glue to dry before they slapped the patch on there. Some
> > fellows lit the glue on fire before they slapped the patch on there.
> > In and out in 20 minutes. That was the rule. They didn't have time
> > for fiddling.

(JB's response):
> The amount of stretch in a bicycle tube to fill the volume of a tire
> casing is far greater than that of car and truck tires of old. Tube
> separation from a patch is fairly universal with patches on bicycle
> tubes that are ridden immediately after application. The truck tire
> tube does not stretch sufficiently to cause separation.

I can't say about the non-tubeless auto/truck tires of old, which
would be my only exposure to said articles, but as a bike tire tube is
filled with air, about the time it has much rigidity, it pretty well
fills the tire. At least mine, chosen for matching-to-tire size, seem
to. I'm guessing other factors play a part:

Back in the semi-prehistoric past, I remember watching a tube being
patched in a repair shop. They had a shoe, resembling a cobbler's
last:

<http://www.antiquemystique.com/pages/2716_jpg.htm>

which the tube was hard-stretched over. I'm guessing the "glue" was in
some sort of lidded can, perhaps a screw-top; whether it was "fresher"
than a crimped tube carried on bikes is unknowable, but certainly
possible, also due to professional concerns and daily use. Once the
patch was applied, a wheeled tool (mentioned but unfortunately not
shown here):

<http://books.google.com/books?
id=7aI7AAAAMAAJ&pg=PA1102&lpg=PA1102&dq=toothed+wheel+tire
+repair&source=web&ots=MGLFQTztVo&sig=w5_uknnRGuqxzEUxvUhM3FYKlRg#PPA1141,M1>

TinyURL: http://tinyurl.com/3x8vn4

> was run back and forth over the patch with some force, perhaps starting in the center and working out, with the intent of "stitching" the patch down tight.

As I recall, it was the practice of those ancient times to re-mount
the freshly "patched tire" on the vehicle, so the spare could be
returned to proper duty and the "bumper jack" (as they were called
then) could be left safely in the trunk.

> I hope you can visualize that when expanded to fill the tire, the
> patch is held firmly against the casing while the tube at the hole can
> pull away, air pressure entering into the tiny annular gap around the
> perforation.

Just offhand, I'd guess Vey is OK with that verbiage. Of course, the
"tiny annular gap" has become something of a conduit, if not a
complete flapper, by the time the bike goes thump thump thump.

Jobst, I read your post (anonymous synonymous with "snipe"???), and
frankly, it sounded like someone burned the bird yesterday.

I hope you never get so involved with being old that you start giving
away the days that remain, as you have a lot to offer.

As ever, --D-y

[jobst.brandt@stanfordalumni.org]

Chalo Colina writes:

>> This reminds me of the REMA representative at InterBike in 2006 who
>> was not aware that his patches take time to cure and that a fresh
>> patch can be pulled off with ease while a day-old one cannot.

>> That is how little practical understanding of tire patching anyone
>> at REMA seems to have. They still believe patches are held best if
>> the surface of the tube is "roughened". Many of my patch kits of
>> the past had cheese graters for that purpose. That's how bad
>> things are in the business.

> Maybe you'd get better immediate adhesion if you used a bit of
> sandpaper (the new cheese grater) to rough up the patched area
> first. In addition to increasing the surface area for the glue to
> act upon, it also has the effect of breaking up and removing the
> coating of mold release as well as leveling any seams or ribs on the
> tube surface.

> I always sand the tube thoroughly enough to remove the waxy whitish
> surface layer and leave only fresh black butyl for the glue to stick
> to. I have no problems with patches lifting, even when they are
> placed into service right after a repair.

http://www.sheldonbrown.com/brandt/patching.html

You must have missed that.

Jobst Brandt

[Werehatrack]

On Wed, 21 Nov 2007 00:07:01 -0800 (PST), Chalo
<chalo.colina@gmail.com> may have said:

>Jobst Brandt wrote:
>>
>> This reminds me of the REMA representative at InterBike in 2006 who
>> was not aware that his patches take time to cure and that a fresh
>> patch can be pulled off with ease while a day-old one cannot.
><snip>
>> That is how little practical understanding of tire patching anyone at
>> REMA seems to have. They still believe patches are held best if the
>> surface of the tube is "roughened". Many of my patch kits of the past
>> had cheese graters for that purpose. That's how bad things are in the
>> business.
>
>Maybe you'd get better immediate adhesion if you used a bit of
>sandpaper (the new cheese grater) to rough up the patched area first.
>In addition to increasing the surface area for the glue to act upon,
>it also has the effect of breaking up and removing the coating of mold
>release as well as leveling any seams or ribs on the tube surface.
>
>I always sand the tube thoroughly enough to remove the waxy whitish
>surface layer and leave only fresh black butyl for the glue to stick
>to. I have no problems with patches lifting, even when they are
>placed into service right after a repair.

My experience mirrors that of Jobst closely, though your methods also
work. IME, a fresh patch will *usually* hold if applied to a clean
surface free of mold release compound, but if allowed to sit
unstressed for a day before being placed into service, it's well and
truly impossible to pull loose intact...however a patch applied to an
uncleaned surface may not stick at all. At the same time, a freshly
applied patch on a well-cleaned tube can still be peeled loose with
relative ease for at least an hour, regardless of whether the surface
is roughened.

I carry emery cloth and boards for the purpose of removing mold ridges
in the vicinity of the puncture. I've had good results from cleaning
the tube surface with one liberal application of patch cement which is
immediately wiped off. I find no difference in results between
roughened and merely solvent- or cement-cleaned tube surfaces as long
as there are no ridges passing under the tube to create a bond failure
channel.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

[A Muzi]

>>> This reminds me of the REMA representative at InterBike in 2006 who
>>> was not aware that his patches take time to cure and that a fresh
>>> patch can be pulled off with ease while a day-old one cannot.

>>> That is how little practical understanding of tire patching anyone
>>> at REMA seems to have. They still believe patches are held best if
>>> the surface of the tube is "roughened". Many of my patch kits of
>>> the past had cheese graters for that purpose. That's how bad
>>> things are in the business.

> Chalo Colina writes:
>> Maybe you'd get better immediate adhesion if you used a bit of
>> sandpaper (the new cheese grater) to rough up the patched area
>> first. In addition to increasing the surface area for the glue to
>> act upon, it also has the effect of breaking up and removing the
>> coating of mold release as well as leveling any seams or ribs on the
>> tube surface.
>> I always sand the tube thoroughly enough to remove the waxy whitish
>> surface layer and leave only fresh black butyl for the glue to stick
>> to. I have no problems with patches lifting, even when they are
>> placed into service right after a repair.

jobst.brandt@stanfordalumni.org wrote:
> http://www.sheldonbrown.com/brandt/patching.html
> You must have missed that.

Patching is also quick and effective on surfaces cleaned with MEK or
trichlor but few (any??) riders carry such!

In my class, I advise not touching the cleaned area after
sanding/scuffing. Cement may be easily spread with the end of the tube
instead of a finger. In my experience oily fingers are a common cause of
patch 'failure'.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

[Chalo]

Werehatrack wrote:
>
> IME, a fresh patch will *usually* hold if applied to a clean
> surface free of mold release compound, but if allowed to sit
> unstressed for a day before being placed into service, it's well and
> truly impossible to pull loose intact...however a patch applied to an
> uncleaned surface may not stick at all. At the same time, a freshly
> applied patch on a well-cleaned tube can still be peeled loose with
> relative ease for at least an hour, regardless of whether the surface
> is roughened.

There's one more thing I do that may account for relatively trouble-
free patching on the road-- I use a tube as close as possible to the
same size as the tire it goes in, so it isn't terribly stretched by
the time it's squeezed against the tire casing upon inflation. That
usually means fitting a tube with a larger nominal size than that of
the tire, e.g a 700x40-45 tube in a 700x38 tire.

Chalo

[Tom Sherman]

Chalo Colina wrote:
> Werehatrack wrote:
>> IME, a fresh patch will *usually* hold if applied to a clean
>> surface free of mold release compound, but if allowed to sit
>> unstressed for a day before being placed into service, it's well and
>> truly impossible to pull loose intact...however a patch applied to an
>> uncleaned surface may not stick at all. At the same time, a freshly
>> applied patch on a well-cleaned tube can still be peeled loose with
>> relative ease for at least an hour, regardless of whether the surface
>> is roughened.
>
> There's one more thing I do that may account for relatively trouble-
> free patching on the road-- I use a tube as close as possible to the
> same size as the tire it goes in, so it isn't terribly stretched by
> the time it's squeezed against the tire casing upon inflation. That
> usually means fitting a tube with a larger nominal size than that of
> the tire, e.g a 700x40-45 tube in a 700x38 tire.

Does the diameter of the tire/tube make any difference? I, like Chalo,
use tires wider and at a lower pressure than most "roadies", and have
not had problems with patches coming off, even when put back into use
shortly after patching.

Do ATB riders generally have less problems with patches sticking than
road bicycle riders? (One would think they would get fewer punctures due
to tires with heavier casings and thicker tread.)

--
Tom Sherman - Holstein-Friesland Bovinia
"Localized intense suction such as tornadoes is created when temperature
differences are high enough between meeting air masses, and can impart
excessive energy onto a cyclist." - Randy Schlitter

[Werehatrack]

On Fri, 23 Nov 2007 13:09:42 -0800 (PST), Chalo
<chalo.colina@gmail.com> may have said:

>There's one more thing I do that may account for relatively trouble-
>free patching on the road-- I use a tube as close as possible to the
>same size as the tire it goes in, so it isn't terribly stretched by
>the time it's squeezed against the tire casing upon inflation. That
>usually means fitting a tube with a larger nominal size than that of
>the tire, e.g a 700x40-45 tube in a 700x38 tire.

That practice will serve you well in my experience, and I use similar
tactics myself whenever possible.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

[jobst.brandt@stanfordalumni.org]

Tom Sherman writes:

>>> IME, a fresh patch will *usually* hold if applied to a clean
>>> surface free of mold release compound, but if allowed to sit
>>> unstressed for a day before being placed into service, it's well
>>> and truly impossible to pull loose intact...however a patch
>>> applied to an uncleaned surface may not stick at all. At the same
>>> time, a freshly applied patch on a well-cleaned tube can still be
>>> peeled loose with relative ease for at least an hour, regardless
>>> of whether the surface is roughened.

>> There's one more thing I do that may account for relatively
>> trouble- free patching on the road-- I use a tube as close as
>> possible to the same size as the tire it goes in, so it isn't
>> terribly stretched by the time it's squeezed against the tire
>> casing upon inflation. That usually means fitting a tube with a
>> larger nominal size than that of the tire, e.g a 700x40-45 tube in
>> a 700x38 tire.

> Does the diameter of the tire/tube make any difference? I, like
> Chalo, use tires wider and at a lower pressure than most "roadies",
> and have not had problems with patches coming off, even when put
> back into use shortly after patching.

Of course it does. As the tire is inflated the tube stretches to the
inside diameter of the tire and in so doing also stretches the patch
that is somewhat less stretchable than the tube. That causes a shear
force (in the adhesive interface) and a tendency for the stretched tub
to remain at its stress free cross section.

In this condition, air pressure does not guarantee that the tube is
pressed against the patch around the hole because air pressure is
retained by the patch underside. With diagonal massage from a bias
ply casing, this separates the tube from the patch and allows it to
shrink to its uninflated cross section... up to the edge of the patch
that is feathered out to zero thickness leaving no difference in
stretch forces.

> Do ATB riders generally have less problems with patches sticking
> than road bicycle riders? (One would think they would get fewer
> punctures due to tires with heavier casings and thicker tread.)

That depends on the ratio between tire internal cross section and tube
size. The larger a tire cross section the less difference there need
be to prevent wrinkles, so the tube may be close to its inflated cross
section from the start.

Jobst Brandt