Patch peeling, Drying time and other misdirection

I think Jobst owes us and the REMA rep that he has been maligning for
years a little proof.

Jobst believes that if you can peel a fresh patch off, it is
inadequately adhered and that only HE understands the truly correct
method of applying a patch.
In a masterful misdirection, Jobst has not established (nor even
suggested) that a fresh patch using HIS method is not "peelable" when
fresh.

Carefully avoiding an apples-to-apples comparison Jobst slanders the
REMA rep's "fresh" patch while referring only to "Jobstian" patches
which Jobst acknowledges require time to cure.

Of course he adds in a number of other diversions, cellophane and
such.

Here's another simple experiment (which I have suggested directly to
Jay B. elsewhe

Apparatus needed:
1. A tube to serve as a test platform
2. Patching materials including 5 patches
Time involved - less than ten minutes

All of this presumes following standard instructions (aside from
drying time) .
Such as those found he
http://www.rematiptop.com/technical/...zing-Fluid.pdf

1. Prepare a large patch test area on the tube.
2. Cover the area with a layer of patch adhesive
3. Then as the adhesive is drying, apply patches at 1 minute
intervals.
(that should give us patches at 1, 2, 3, 4 and 5 minutes, it might
even be worth adding one at a more extended time, like 15 minutes)

4. After the last patch is dry, try to peel the patches off.

Now I speculate that ALL patches will be removable.
The point is to determine the significance of the drying time of the
glue _at the time of patch application_.

Why? Because of Jobst's suggestion that a patch which is "peelable"
immediately after application is defective and this results from the
glue being too dry.

I think everyone would expect a patch applied to wet adhesive to be
peelable.
And Jobst is adamant that a patch applied to "dry" glue (5 minutes
minimum is the REMA instruction) is peelable.
So by this individual's hypothesis, there some "magic" point in this
5 minute span at which application must result in an "unpeelable"
patch.

That does not seem likely, but that's why this experiment is in order.

Of course if ALL fresh patches are peelable, no conclusion can be
drawn about any fresh patch which is peelable. Jobst would need to
reconsider his five year rant about the REMA rep and the rest of the
industry.

As I have discussed elsewhere, peelability of a fresh patch is not
likely an accurate measure of whether the patch is "good," but Jobst
has assumed that so the above experiment will demonstrate whether he
has established any actual distinction between his patching method and
that promoted by the manufacturers.

I expect Jobst himself will not respond, or if he does it will begin
"Apparently you missed where I described ..."

The only thing I have missed is the apples-to-apples comparison which
is necessary for any of Jobst's REMA rant to be of any significance
other than in Jobst's mind.

DR

On 9/21/2010 11:20 AM, DirtRoadie wrote:
I think Jobst owes us and the REMA rep that he has been maligning for
years a little proof.

Jobst believes that if you can peel a fresh patch off, it is
inadequately adhered and that only HE understands the truly correct
method of applying a patch.
In a masterful misdirection, Jobst has not established (nor even
suggested) that a fresh patch using HIS method is not "peelable" when
fresh.

Carefully avoiding an apples-to-apples comparison Jobst slanders the
REMA rep's "fresh" patch while referring only to "Jobstian" patches
which Jobst acknowledges require time to cure.

Of course he adds in a number of other diversions, cellophane and
such.

Here's another simple experiment (which I have suggested directly to
Jay B. elsewhe

Apparatus needed:
1. A tube to serve as a test platform
2. Patching materials including 5 patches
Time involved - less than ten minutes

All of this presumes following standard instructions (aside from
drying time) .
Such as those found he
http://www.rematiptop.com/technical/...zing-Fluid.pdf

1. Prepare a large patch test area on the tube.
2. Cover the area with a layer of patch adhesive
3. Then as the adhesive is drying, apply patches at 1 minute
intervals.
(that should give us patches at 1, 2, 3, 4 and 5 minutes, it might
even be worth adding one at a more extended time, like 15 minutes)

4. After the last patch is dry, try to peel the patches off.

Now I speculate that ALL patches will be removable.
The point is to determine the significance of the drying time of the
glue _at the time of patch application_.

Why? Because of Jobst's suggestion that a patch which is "peelable"
immediately after application is defective and this results from the
glue being too dry.

I think everyone would expect a patch applied to wet adhesive to be
peelable.
And Jobst is adamant that a patch applied to "dry" glue (5 minutes
minimum is the REMA instruction) is peelable.
So by this individual's hypothesis, there some "magic" point in this
5 minute span at which application must result in an "unpeelable"
patch.

That does not seem likely, but that's why this experiment is in order.

Of course if ALL fresh patches are peelable, no conclusion can be
drawn about any fresh patch which is peelable. Jobst would need to
reconsider his five year rant about the REMA rep and the rest of the
industry.

As I have discussed elsewhere, peelability of a fresh patch is not
likely an accurate measure of whether the patch is "good," but Jobst
has assumed that so the above experiment will demonstrate whether he
has established any actual distinction between his patching method and
that promoted by the manufacturers.

I expect Jobst himself will not respond, or if he does it will begin
"Apparently you missed where I described ..."

The only thing I have missed is the apples-to-apples comparison which
is necessary for any of Jobst's REMA rant to be of any significance
other than in Jobst's mind.

The question is about the nature of the patch/tube bond. Some say it is
"mechanical", effected by the drying of the glue (evaporation of
solvents), others say it's chemical via a vulcanization and
crosslinking. In either case, the patch would be peelable immediately --
applied wet or dry -- the former because the glue would still be liquid,
the latter because vulcanization hadn't occurred. The next day, both
would not be easily peelable, that also being predicted by either
explanation.

The real question is whether the dry patch adheres as well as the wet
patch after some interval (say a day), and whether the dry patch, when
used immediately, runs any significant risk of lifting and/or leaking.

I ride on fresh (dry) patches without leaks. Cutting up several old
patches shows no sign of lifting, either in the center or the edges.
Peeling those old patches is quite difficult. I don't know of anything
unique about my tubes, patches, or technique.

I just follow the directions, as I have since perhaps the late 60's. I
never gave it any thought or had any problems. I have worked with a wide
variety of adhesives, and typically have a large collection on hand for
various purposes. I just follow the directions for all of them. Waiting
for a film to completely dry is also the indicated way to use contact
cement.

If the tire patch reaction wasn't driven by vulcanization, I don't know
why they would include a vulcanizing agent in the glue, nor why they'd
instruct you to let the glue film dry completely before applying the
patch. It shouldn't bond at all (dry) if it was a mechanical bond, yet
it bonds extremely well.

The adhesive industry has the term "green strength", which characterizes
the initial, not fully cured, bond strength. My experience with dry
patches has been that the green strength is quite sufficient for
immediate riding. That is also implied by the patch directions.

I see no mystery in the cellophane cover, nor any effect from removing
or leaving. This tempest in a teapot seems about solving a non-problem.
The instructions are simple, patches weren't designed for rubber
chemists or mechanical engineers, but being designed by rubber chemists,
perhaps they're not easily understood by mechanical engineers.

On Sep 21, 11:21*am, Peter Cole wrote:
On 9/21/2010 11:20 AM, DirtRoadie wrote:
No disagreements but ...

The question is about the nature of the patch/tube bond. Some say it is
"mechanical", effected by the drying of the glue (evaporation of
solvents), others say it's chemical via a vulcanization and
crosslinking. In either case, the patch would be peelable immediately --

Yes

applied wet or dry -- the former because the glue would still be liquid,
the latter because vulcanization hadn't occurred. The next day, both
would not be easily peelable, that also being predicted by either
explanation.

The real question is whether the dry patch adheres as well as the wet
patch after some interval (say a day), and whether the dry patch, when
used immediately, runs any significant risk of lifting and/or leaking.

That's true, too, and is the converse of what I suggested. Jobst
scathingly attacks the REMA rep yet has made no suggestion that the
REMA reps patch would not have been "bombproof" after a day.

I ride on fresh (dry) patches without leaks. Cutting up several old
patches shows no sign of lifting, either in the center or the edges.
Peeling those old patches is quite difficult. I don't know of anything
unique about my tubes, patches, or technique.

Noted

I just follow the directions, as I have since perhaps the late 60's. I
never gave it any thought or had any problems. I have worked with a wide
variety of adhesives, and typically have a large collection on hand for
various purposes. I just follow the directions for all of them. Waiting
for a film to completely dry is also the indicated way to use contact
cement.


If the tire patch reaction wasn't driven by vulcanization, I don't know
why they would include a vulcanizing agent in the glue, nor why they'd
instruct you to let the glue film dry completely before applying the
patch. It shouldn't bond at all (dry) if it was a mechanical bond, yet
it bonds extremely well.

Also noted, but bottom line is - it works.

The adhesive industry has the term "green strength", which characterizes
the initial, not fully cured, bond strength. My experience with dry
patches has been that the green strength is quite sufficient for
immediate riding. That is also implied by the patch directions.

Yes - operative word "sufficient." The fact that a patch may be
stronger tomorrow than it is today does not establish that it is
insufficient today. And even the fact that a patch can be "peeled"
today, does not demonstrate that it has insufficient shear strength
today.

I see no mystery in the cellophane cover, nor any effect from removing
or leaving. This tempest in a teapot seems about solving a non-problem.
The instructions are simple, patches weren't designed for rubber
chemists or mechanical engineers, but being designed by rubber chemists,
perhaps they're not easily understood by mechanical engineers.

Yes, discussion of the cellophane is smoke and mirrors.

Thanks for the input.
DR

On 21 Sep 2010 17:46:50 GMT, Jobst Brandt wrote:

van der Walls forces are not time dependent, as the running Gecko
lizard aptly demonstrates as it runs up a clean window. What takes
time with a patch placed on wet glue is the evaporation time through
the body of the patch, that is made of material that passes these
gases.

Baloney. This mythical patch is expected to pass toluene molecules,
but blocks air? Methinks not.

My guess(tm) is that the molecular diameter of the C6H5CH3 molecule
is about 550 pm (picometers) across. N2 is 155 pm and 02 is 152 pm.
(Incidentally, estimated from van de Waal's radii). No way is a
larger organic molecule going to squeeze through holes in the rubber
patch that will not let much smaller gas molecules pass through. As
far as I'm concerned, the rubber patch is impervious to both gases and
volatized organic solvents. Once you apply the patch, any remaining
volatiles are trapped inside.

I quickly read through two patents on such tire patching:
http://www.google.com/patents/about?id=0udmAAAAEBAJ&dq=3,009,846&output=text
http://www.google.com/patents/about?id=gAxmAAAAEBAJ&dq=2638955
and found no mention of the permeability of the patch to either air or
solvents. If this were a characteristic necessary for proper
function, I'm sure it would have been mentioned by the inventor.





--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On 9/21/2010 1:46 PM, Jobst Brandt wrote:
Peter Cole wrote:

The real question is whether the dry patch adheres as well as the
wet patch after some interval (say a day), and whether the dry
patch, when used immediately, runs any significant risk of lifting
and/or leaking.

It is as likely as the failure of glue-less patches. With the REMA
patch applied to dry glossy rubber cement, it has become a glue-less
patch whose failure mode is like those of glue-less patches.

No, I don't think it has. I also have had a fair amount of experience
with those. I found them unreliable, even at low fat tire pressures.
They tended to leak after some months and were difficult to then remove
& repatch.


If the tire patch reaction wasn't driven by vulcanization, I don't
know why they would include a vulcanizing agent in the glue, nor why
they'd instruct you to let the glue film dry completely before
applying the patch. It shouldn't bond at all (dry) if it was a
mechanical bond, yet it bonds extremely well.

The adhesive industry has the term "green strength", which
characterizes the initial, not fully cured, bond strength. My
experience with dry patches has been that the green strength is
quite sufficient for immediate riding. That is also implied by the
patch directions.

van der Walls forces are not time dependent, as the running Gecko
lizard aptly demonstrates as it runs up a clean window. What takes
time with a patch placed on wet glue is the evaporation time through
the body of the patch, that is made of material that passes these
gases.

What also takes time is vulcanization. That strength improves with
"cure" is obvious. What is under contention is the curing mechanism.


I see no mystery in the cellophane cover, nor any effect from
removing or leaving. This tempest in a teapot seems about solving a
non-problem. The instructions are simple, patches weren't designed
for rubber chemists or mechanical engineers, but being designed by
rubber chemists, perhaps they're not easily understood by mechanical
engineers.

I don't understand what point you are making for or against the
cellophane cover. It's removal facilitates evaporation of glue
volatiles.

I'm not making a case for either. My volatiles are long gone when I
apply the patch, so I don't care if the cellophane has an effect or not.

On 9/21/2010 1:40 PM, DirtRoadie wrote:
On Sep 21, 11:21 am, Peter wrote:

The adhesive industry has the term "green strength", which characterizes
the initial, not fully cured, bond strength. My experience with dry
patches has been that the green strength is quite sufficient for
immediate riding. That is also implied by the patch directions.

Yes - operative word "sufficient." The fact that a patch may be
stronger tomorrow than it is today does not establish that it is
insufficient today. And even the fact that a patch can be "peeled"
today, does not demonstrate that it has insufficient shear strength
today.

I said "quite" sufficient, because it's, in my experience, better than
sufficient in that I have had no failures at all that I can remember.


I see no mystery in the cellophane cover, nor any effect from removing
or leaving. This tempest in a teapot seems about solving a non-problem.
The instructions are simple, patches weren't designed for rubber
chemists or mechanical engineers, but being designed by rubber chemists,
perhaps they're not easily understood by mechanical engineers.

Yes, discussion of the cellophane is smoke and mirrors.

Thanks for the input.

You don't have to thank me, and, given the context, I wish you wouldn't.

On Tue, 21 Sep 2010 11:17:05 -0700, Jeff Liebermann
wrote:

My guess(tm) is that the molecular diameter of the C6H5CH3 molecule
is about 550 pm (picometers) across. N2 is 155 pm and 02 is 152 pm.

Ooops. Bad guess(tm) due to haste (and numerous interruptions).
I got the bond lenths and angles right, but forgot to include the
diameter of the various atoms.

N2 is about 300 pm and O2 is about 292 pm. C6H5CH3 781 pm
Tolune is a much larger molecule than oxygen or nitrogen.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On 2010-09-21, Jobst Brandt wrote:
[...]
Yes, discussion of the cellophane is smoke and mirrors.

So why is that cover on the patch at all? Other patch manufacturers
don't use such a cover.

It's to protect the rather thin bits of rubber at the edges as you put
the patch on, as the patent said.

Jobst Brandt wrote:
Someone wrote:

No disagreements but ...

The question is about the nature of the patch/tube bond. Some say
it is "mechanical", effected by the drying of the glue (evaporation
of solvents), others say it's chemical via a vulcanization and
crosslinking. In either case, the patch would be peelable
immediately --

Yes

applied wet or dry -- the former because the glue would still be
liquid, the latter because vulcanization hadn't occurred. The next
day, both would not be easily peelable, that also being predicted
by either explanation.

The real question is whether the dry patch adheres as well as the
wet patch after some interval (say a day), and whether the dry
patch, when used immediately, runs any significant risk of lifting
and/or leaking.

That's true, too, and is the converse of what I suggested. Jobst
scathingly attacks the REMA rep yet has made no suggestion that the
REMA reps patch would not have been "bombproof" after a day.

The REMA man said his patch was "bombproof" and that is why he handed
it to me for inspection. He was trying to disprove my method of
making a "bombproof" patch... but failed.

I ride on fresh (dry) patches without leaks. Cutting up several old
patches shows no sign of lifting, either in the center or the
edges. Peeling those old patches is quite difficult. I don't know
of anything unique about my tubes, patches, or technique.

Noted

I just follow the directions, as I have since perhaps the late
60's. I never gave it any thought or had any problems. I have
worked with a wide variety of adhesives, and typically have a large
collection on hand for various purposes. I just follow the
directions for all of them. Waiting for a film to completely dry
is also the indicated way to use contact cement.

If the tire patch reaction wasn't driven by vulcanization, I don't
know why they would include a vulcanizing agent in the glue, nor
why they'd instruct you to let the glue film dry completely before
applying the patch. It shouldn't bond at all (dry) if it was a
mechanical bond, yet it bonds extremely well.

Also noted, but bottom line is - it works.

The adhesive industry has the term "green strength", which
characterizes the initial, not fully cured, bond strength. My
experience with dry patches has been that the green strength is
quite sufficient for immediate riding. That is also implied by the
patch directions.

Yes - operative word "sufficient." The fact that a patch may be
stronger tomorrow than it is today does not establish that it is
insufficient today. And even the fact that a patch can be "peeled"
today, does not demonstrate that it has insufficient shear strength
today.

Patches fail in peeling mode, so that is germane.

I see no mystery in the cellophane cover, nor any effect from
removing or leaving. This tempest in a teapot seems about solving
a non-problem. The instructions are simple, patches weren't
designed for rubber chemists or mechanical engineers, but being
designed by rubber chemists, perhaps they're not easily understood
by mechanical engineers.

Yes, discussion of the cellophane is smoke and mirrors.

So why is that cover on the patch at all? Other patch manufacturers
don't use such a cover.

Most do have a cellophane or paper cover. It makes the patch more
substantial to handle and apply (which especially helps when the edges are
thin and feathered), and saves you touching the underside of the patch.

On Sep 21, 12:29*pm, Jobst Brandt wrote:
The REMA man said his patch was "bombproof" and that is why he handed
it to me for inspection. *

So he LIED to you? Is that what this is all about?

He was trying to disprove my method of
making a "bombproof" patch... but failed.

How did he fail? Did you demonstrate your method on the spot for
comparison? You have never mentioned that. So was your patch
peelable?

Patches fail in peeling mode, so that is germane.
That's an interesting and broad generalization. Describe how that
happens other than in a case where you are grasping the patch and
peeling it.

I see no mystery in the cellophane cover, nor any effect from
Yes, discussion of the cellophane is smoke and mirrors.

So why is that cover on the patch at all? *Other patch manufacturers
don't use such a cover.

Among other things, it's a convenient "handle."

DR