Elmer's Rubber Cement is not the vulcanizing kind!

In article ,
(Tom Keats) wrote:

In article ,
Michael Press writes:
In article ,
(Tom Keats) wrote:

Now I'm wondering
how those long polymers find their ways into their holes
or ruts or whatever allows them to interdigitate -- do
they just fall in when a hole opens up beneath them,
or do they just randomly flow around until they drop
into a hole/rut/whatever? If they're electrically drawn
in, could that arguably be a chemical process?

Physically it is similar to interleaving the pages of
two books.

Interleaving the pages of two books requires thought
and intention and maybe a little cleverness, if the
job is to be done neatly, without collisions.

What forces are at work with this interdigitation/
interleaving? What downright ~makes~ polymers
first agree to interdigitate, and then move around
to align themselves accordingly? Or is this just
another one of those axiomatic things?

Adjacent books don't suddenly decide to interleave
their pages, neither does a jumbled pile of bricks
decide to form a chimney. So I'm having difficulty
with the concept of molecular chains somehow elegantly
and neatly (but non-chemically) organizing themselves
by dint of their proximity to each other.

We're being told one substance somehow molecularly
intimates and intermingles itself with another
similar substance, and yet the process is not
chemical.

BTW, as a preemptive afterthought: Jim Beam and the
horse he rode into town on can both enjoy precious
moments with their respective selves.

Or each other, if they're into that.

The interleaved page analogy is to illustrate
the scale of the forces at work. You did not know that?

Here is another analogy: Wet down a newspaper.
Allow it to dry. Now pick the pages apart.
Each page retains its integrity, though it
has partially intermixed with adjacent pages.
First the fibers swell up with adsorbed liquid,
fibers at the face of one piece fall into
valleys in the other piece.

--
Michael Press

On Apr 26, 9:15*am, Still Just Me
wrote:
On Sun, 26 Apr 2009 04:51:06 -0700 (PDT),
wrote:

On further investigation it seems that some bicycle tire tube patch
adhesives may indeed contain rubber vulcanization accelerators. For
example the MSDS(Material Data Safety Sheet) for REMA Tip Top
Vulcanizing Fluid CFC Free indicates that it contains 1.0 – 2.5 %Wt of
N-Ethylcyclohexylamine, an amine having a *number of commercial
applications including use in rubber formulations. The general
mechanism of tube patch adhesion remains, I believe, as indicated
above.

So, bottom line what are the recommended glues?

I don't use patch kits, I've always just used a piece of tube to
patch. Patch kits always seemed like a very expensive way to get a
very small tube of cement and some precut rubber in a small box.

What's a suggested glue for tube on tube patching?

I'm no expert, but it may be best to spend the money and buy a little
Rema kit that has adhesive and patches that work very well together.

The rubber used in rubber cements such as Elmer's may have a lower
cohesive strength that makes it better suited to its primary use of
adhering paper to paper with a removable bond.

___

Spike

On 27 Apr, 01:47, wrote:
Michael Press wrote:
Now I'm wondering how those long polymers find their ways into
their holes or ruts or whatever allows them to interdigitate -- do
they just fall in when a hole opens up beneath them, or do they
just randomly flow around until they drop into a hole/rut/whatever?
If they're electrically drawn in, could that arguably be a chemical
process?
Physically it is similar to interleaving the pages of two books.
The force to pull them apart is enormous. *It is not a chemical
process because chemical bonds are not changed. *Very roughly, a
chemical bond changes when one or more electrons move permanently
from one orbit to another.
Vulcanizing rubber is a one way street chemically. *Rubber is melted
with sulfur whence cross links form between polymers. *This cross
linking cannot be undone to get back to the original constituents.

This sounds as though a REMA patch, once vulcanized, cannot be
removed. *I find heating the patch on a flat surface (frying pan under
thumb pressure) to be an effective way of making well cured patches
removable. *From all the chemistry in this thread, it seems my method
of applying the REMA patch, as soon as the vulcanizing fluid is no
longer liquid, seems to be more conducive to polymerizing than waiting
for it to completely dry and before use, allowing patches to become
well adhered in several hours, seems also to be borne out.

In any event, having removed many leaky patches, that were ridden
immediately after patching, has shown me that they lift off, almost to
their edge as I described, developing a domed pocket containing talcum
from inside the inner tube.


And why do you continue to persist in doing it wrong? And then tell
everone you cant do what others can with a Rema patch kit? To save
you further embarressment get some lighter fluid (high fraction
petroleum) clean shirting and a small spoon with a smooth rounded
metal handle, we call em teaspoons. Find hole, wet tube with spirit,
rub with shirting, wet again, rub with clean area of shirting, clean
end of spoon with last wet bit of shirting, quickly now, rub tube with
spoon handle until it becomes hot, the tube will now be sticky, put
rubber solution on to clean cold spoon handle(another one), wipe
quickly across area to be patched, it will dry in seconds, apply clean
new patch, burnish the back with the warm spoon, continue until hot.
Never fails, whatever kit used. Old technique recently remembered.

On 27 Apr, 02:16, wrote:
On Apr 26, 9:15*am, Still Just Me
wrote:



On Sun, 26 Apr 2009 04:51:06 -0700 (PDT),
wrote:

On further investigation it seems that some bicycle tire tube patch
adhesives may indeed contain rubber vulcanization accelerators. For
example the MSDS(Material Data Safety Sheet) for REMA Tip Top
Vulcanizing Fluid CFC Free indicates that it contains 1.0 – 2.5 %Wt of
N-Ethylcyclohexylamine, an amine having a *number of commercial
applications including use in rubber formulations. The general
mechanism of tube patch adhesion remains, I believe, as indicated
above.

So, bottom line what are the recommended glues?

I don't use patch kits, I've always just used a piece of tube to
patch. Patch kits always seemed like a very expensive way to get a
very small tube of cement and some precut rubber in a small box.

What's a suggested glue for tube on tube patching?

I'm no expert, but it may be best *to spend the money and buy a little
Rema kit that has adhesive and patches that work very well together.

The rubber used in rubber cements such as Elmer's may have a lower
cohesive strength that makes it better suited to its primary use of
adhering paper to paper with a removable bond.

If a thin enough applcation can be made with latex solution, then it
is suitable for patching, particularly if you heat the tube first.

Michael Press wrote:
In article ,
(Tom Keats) wrote:

In article ,
writes:

"When rubber cement is used to bond rubber to itself, the solvent in
the cement swells the substrates somewhat and facilitates the
interdigitation process. After the solvent evaporates, it is hard to
distinguish just where the joint lies.
Okay, but I still nevertheless perceive something going on
that intimates a patch together with the inner tube to
which it is applied.

The bonding force is not a
chemical bond -- no bonds are made or broken; the strength of the bond
is purely a physical phenomenon involving van der Walls and London
forces between two intimately mixed and chemically similar non-polar
hydrocarbon rubber molecules."
http://www.madsci.org/posts/archives...3004.Ch.r.html
I intuit there's something further happening. The
patch doesn't just lie there on the tube like a
flapjack; it's as if the tube is sucking the patch
onto itself. The patch & tube aren't just holding
hands and interdigitating -- they're really cleaving
unto each other and becoming one flesh, like Adam & Eve.

And with that imagery, I think I'll forego this line
of curiosity. It's enough to know how to successfully
patch a tube, without getting into all the messy,
gruesome details. Some things in life are best
left as wonderments. As long as one gets away with
not getting the patch kit instruction sheet inextricably
stuck to their thumb, life is good.

Remove a well adhered patch. You will see no indication
of chemical bond formation.


if you cut a piece of rubber, how will you see evidence of chemical bond
formation?

wrote:
On Apr 26, 9:15�am, Still Just Me
wrote:
On Sun, 26 Apr 2009 04:51:06 -0700 (PDT),
wrote:

On further investigation it seems that some bicycle tire tube patch
adhesives may indeed contain rubber vulcanization accelerators. For
example the MSDS(Material Data Safety Sheet) for REMA Tip Top
Vulcanizing Fluid CFC Free indicates that it contains 1.0 � 2.5 %Wt of
N-Ethylcyclohexylamine, an amine having a �number of commercial
applications including use in rubber formulations. The general
mechanism of tube patch adhesion remains, I believe, as indicated
above.
So, bottom line what are the recommended glues?

I don't use patch kits, I've always just used a piece of tube to
patch. Patch kits always seemed like a very expensive way to get a
very small tube of cement and some precut rubber in a small box.

What's a suggested glue for tube on tube patching?

I'm no expert, but it may be best to spend the money and buy a little
Rema kit that has adhesive and patches that work very well together.

The rubber used in rubber cements such as Elmer's may have a lower
cohesive strength that makes it better suited to its primary use of
adhering paper to paper with a removable bond.

___

Spike


no ****.

wrote:
Michael Press wrote:

Now I'm wondering how those long polymers find their ways into
their holes or ruts or whatever allows them to interdigitate -- do
they just fall in when a hole opens up beneath them, or do they
just randomly flow around until they drop into a hole/rut/whatever?
If they're electrically drawn in, could that arguably be a chemical
process?

Physically it is similar to interleaving the pages of two books.
The force to pull them apart is enormous. It is not a chemical
process because chemical bonds are not changed. Very roughly, a
chemical bond changes when one or more electrons move permanently
from one orbit to another.

Vulcanizing rubber is a one way street chemically. Rubber is melted
with sulfur whence cross links form between polymers. This cross
linking cannot be undone to get back to the original constituents.

This sounds as though a REMA patch, once vulcanized, cannot be
removed. I find heating the patch on a flat surface (frying pan under
thumb pressure) to be an effective way of making well cured patches
removable. From all the chemistry in this thread, it seems my method
of applying the REMA patch, as soon as the vulcanizing fluid is no
longer liquid, seems to be more conducive to polymerizing than waiting
for it to completely dry and before use, allowing patches to become
well adhered in several hours, seems also to be borne out.

In any event, having removed many leaky patches, that were ridden
immediately after patching, has shown me that they lift off, almost to
their edge as I described, developing a domed pocket containing talcum
from inside the inner tube.

jobst, as an analytical thinking exercise, why do you think it may be
that /you/ have all these problems, but those of us that follow
manufacturer instructions, do not?

"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.


Cheers

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.


Cheers



dude, heptane is just the solvent. doesn't mean **** about the bonding
ingredients.

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.


cheers,
Tom

--
Everybody's an expert
I'm really at:
tkeats curlicue vcn dot bc dot ca