Re: Elmer's Rubber Cement is not the vulcanizing kind!
Tom Keats
Tom Sherman <sunsetss000...@yahoo.com> 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
--
Nothing is safe from me.
I'm really at:
tkeats curlicue vcn dot bc dot ca
carl...@comcast.net
Dear Tom,
"Rubber cement works by a mechanism of cohesion [also called
autohesion, or 'self-sticking-to-self] but this is true both for the
paper gluing example and the rubber gluing example, provided there is
cement on both pieces of paper."
"Cohesion occurs when the long polymer chains of the adhesive material
are able to penetrate and mix with the polymer chains of the adherend
[the substrate]. This process is also called 'interdigitation' in
reference to the simile of fingers of opposite hands interlaced, as if
in prayer. It is much harder to separate hands with interlaced fingers
than when the hands simply lay one on the other."
"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. 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/1998-05/893193004.Ch.r.html
Cheers,
Carl Fogel
jim beam
thank you. how many more times we have to hash this through tough
remains to be seen.
jim beam
spelling: "though"
> remains to be seen.
Tom Keats
Thanks, Carl. I'm now edified. I have for a long time
noted how patches seem to be either pulled or pushed
onto the surfaces to which they're adhered, and I've
casually wondered about whatever processes might be
at work, but I've never actually gotten around to
verbially articulating my puzzlement. 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?
I am nevertheless still mystified by how a properly
applied patch seems to be either pushed or pulled
into place, as if an invisible thumb had been pressing
on it all night long. The patch doesn't just lie there
like a fillet of sole or a postage stamp -- some force
has snuggled it intimately right up to the inner tube,
as if patch & tube are spooning. If it's those long
polymer thingies, they must act like an octopus's
tentacles drawing its prey to its beak. But to the
best of my limited knlowledge, molecules don't possess
volition.
I guess the clue lies in whatever keeps an improperly
applied patch from working.
But I have another poser for you, if you're inclined to
spend even more time in response: what does so-called
"vulcanizing" rubber cement do, that non-vulcanizing
rubber cement doesn't?
During my more austere days, I found that vulcanizing
rubber cement works better than non-vulcanizing
rubber cement (or contact cement for that matter) for
minor, external ~tire~ repairs. A swatch of jeans denim
slathered with contact cement makes a fairly usable
internal boot, but you can feel the lump with each
wheel rotation.
Nick L Plate
> In article <vn85v4lh6nujcjme11m3540nb07usb0...@4ax.com>,
> carlfo...@comcast.net writes:
>
>
>
> > On Fri, 24 Apr 2009 20:58:24 -0700, tomke...@bud.garden.local (Tom
> > Keats) wrote:
>
> >>In article <gstp9b$si...@news.motzarella.org>,
It is surface tension which works with an impact contact adhesive, but
it has poor shear strength because it is a long chain non-locked
polymer. It acts like a fluid under constant stress and will tear
apart in time. You need to use a crystalline setting adhesive to
negate the shear problems you are encountering. I've never bothered
to use more adhesive than required to locate the boot after I found
normal contact adhesive does not hold up for long. Useful on the day,
but not for permanent repair. Always use butyl tubes after a
significant boot repair when using normal contact. Always use the
thinnest coat that you can put on both pieces and press together with
an almighty force (once solvent has evaporated), excluding air pockets
at all costs.
Nick L Plate
> In article <vn85v4lh6nujcjme11m3540nb07usb0...@4ax.com>,
> carlfo...@comcast.net writes:
>
>
>
> > On Fri, 24 Apr 2009 20:58:24 -0700, tomke...@bud.garden.local (Tom
> > Keats) wrote:
>
> >>In article <gstp9b$si...@news.motzarella.org>,
... and clean the tube with spirit, then heat the tube before applying
cement by rubbing with the handle of a teaspoon. Spread the cement as
thin as possible with the handle of a cold teaspoon. Always used to
use spoons for puncture repair, but couldn't remember quite why until
I did some tub repairs today. I could only remember using the spoons
as tyre levers. Thirty years later, I now remember there was further
uses for spoons that tyre levers do not satisfy. For four years I
used a bike that was a bit big, so not that much and no punctures
because I wouldn't ride it in the rain with it being too big for me.
It was in this period I forgot how to make a most effective repair.
The bike was transport for baseball games/practice and table tennis
at other times. I couldn't enjoy a distant ride on a large bike.
bjwe...@gmail.com
What is vulcanizing? From
http://en.wikipedia.org/wiki/Vulcanization
"Vulcanization or vulcanisation refers to a specific curing process
of rubber involving high heat and the addition of sulfur or other
equivalent
curatives. It is a chemical process in which polymer molecules are
linked
to other polymer molecules by atomic bridges composed of sulfur atoms
or carbon to carbon bonds. The end result is that the springy rubber
molecules become cross-linked to a greater or lesser extent. This
makes
the bulk material harder, much more durable and also more resistant
to
chemical attack. It also makes the surface of the material smoother
and
prevents it from sticking to metal or plastic chemical catalysts."
And so on. It should be apparent that patch cement
does not "vulcanize." It's a sales term.
I patch tubes with rubber cement out of a jar. My
current jar is Elmer's. I don't have problems with
patches coming off or failing. I've even patched cuts
without an official patch, using rubber cement from
the jar and a piece of old inner tube. You have to be
very scrupulous about removing the mold release
for this to work. I did it as a challenge to see if
I could fix a cut without putting in a very large
stiff patch.
I let the cement dry pretty thoroughly before
applying patches. I also rub them on with a
tire lever end or similar. Contrary to your speculation
about humidity and pressure (the pressure
difference is small and couldn't be significant),
I do most of my patching in low humidity
since I live in a dry place.
IMO, most patch failures are due to improper
preparation or rushing.
Ben
carl...@comcast.net
wrote:
Dear Tom,
Rubber cement works by interdigitation, with no chemical changes. It
doesn't vulcanize the rubber pieces, meaning that no cross-links are
formed and no chemical changes occur.
Cold vulcanizing fluid contains chemicals (the "accelerators" below)
that do produce cross-links between the rubber molecules, just as hot
vulcanizing (heat plus sulphur) changes the chemical structure of
rubber.
The wait-until-tacky prescription for cold vulcanizing fluid has a
surprisingly simple explanation:
"Vulcanizing fluid has two primary functions. First, it contains
chemical accelerators which vulcanize the repair to the tire. Second,
when dry, it leaves the prepared surface tacky, which helps hold the
repair in place until vulcanization occurs."
http://www.premaproducts.com/Technical-Tips.56+M521b3c9abed.0.html
Cheers,
Carl Fogel
carl...@comcast.net
Dear Ben,
Google for "cold vulcanizing fluid"--it's a widely used term in the
industrial belt industry.
Cold vulcanizing fluid simply uses chemicals that produce the
cross-linking that's one of features of hot vulcanization.
In contrast, plain rubber cement works by interdigitation without the
chemical changes of cross-linking--rubber cement isn't cold
vulcanizing fluid.
Cheers,
Carl Fogel
Michael Press
tomk...@bud.garden.local (Tom Keats) wrote:
Air pressure has no first order effect on vapor pressure
of the volatile solvent. Henry's law. A small change in
air pressure implies a third order change in solvent vapor pressure.
--
Michael Press
spiken...@earthlink.net
> In article <gstp9b$si...@news.motzarella.org>,
I believe with respect to bicycle tire tube patch adhesive “Cold
vulcanizing” is a misnomer in so far as it implies that a chemical
reaction is facilitated. Here the “accelerators” – common commercial
organic solvents that under normal conditions do not chemically react
with rubber – function only as a solvent system for both the rubber
dissolved in the so called “cold vulcanizing fluid” and a partial
solvent system for the tube and the patch. This partial solvation
allows for the integration and fusion of the rubber particles of the
tube, adhesive, and the patch into a more or less homogeneous whole.
If these solvents are not allowed to volatilize sufficiently, say for
a period of twenty four hours, the tire rubber and patch rubber may
remain sufficiently solvated to allow for their easy separation. The
dissolved rubber of the tire patch adhesive – the so called “cold
vulcanizing fluid” – retains and thus slows the volatilization of its
solvents allowing for the partial solvation of the patch and tube
rubber by these solvents. There are a myriad of other rubber based
adhesives for different and specialized applications; many certainly
do undergo chemical reactions, and some of these may additionally be
termed “cold vulcanizing”.
___
Spike
Tom Keats
> "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/1998-05/893193004.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.
spiken...@earthlink.net
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.
___
Spike
jim beam
> In article <vn85v4lh6nujcjme1...@4ax.com>,
> carl...@comcast.net 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/1998-05/893193004.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.
oh, for fuck's sake.
> The patch & tube aren't just holding
> hands and interdigitating -- they're really cleaving
> unto each other and becoming one flesh, like Adam & Eve.
get thine dumb religious ass off to school will ya? learn math. learn
chemistry. then quit posting this kind of crap.
>
> 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.
>
>
> cheers,
> Tom
>
>
> --
> Nothing is safe from me.
nothing is safe /for/ the incurably incurious.
jim beam
> On Sun, 26 Apr 2009 04:51:06 -0700 (PDT), spiken...@earthlink.net
> 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.
>
>
> 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?
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]
jim beam
when do we get the review of loctite 404's effectiveness?
Tom Keats
jim beam <retard...@bad.example.net> writes:
>> "Vulcanizing fluid has two primary functions. First, it contains
>> chemical accelerators which vulcanize the repair to the tire. Second,
>> when dry, it leaves the prepared surface tacky, which helps hold the
>> repair in place until vulcanization occurs."
>> http://www.premaproducts.com/Technical-Tips.56+M521b3c9abed.0.html
>>
>> Cheers,
>>
>> Carl Fogel
>
>
> when do we get the review of loctite 404's effectiveness?
When do we get the review of how prune juice and a feed of
sauerkraut plus a couple of fruit smoothies improves an
old-fart sourpuss's outlook, maintains his regularity, and
generally cheers him up, as well as putting a lively glow
in his cheeks?
I love you, too. You remind me of my mom's first in-laws.
They're dead now, and have returned to the flint from which
they were made.
jim beam
i get it. you and chalo. you can't belly up to the facts, so you bleat
some bullshit irrelevance because your freakin' mouth still needs to
work, but you have nothing to actually say.
good luck tom. way to contribute.
Michael Press
tkeat...@hotmail.com (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. 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.
--
Michael Press
Michael Press
Still Just Me <stilln...@stillnodomains.com> wrote:
> On Sun, 26 Apr 2009 04:51:06 -0700 (PDT), spiken...@earthlink.net
> 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 do not use old butyl rubber tubes for patches.
I use high solvent concentration glue and Rema patches.
--
Michael Press
Michael Press
tkeat...@hotmail.com (Tom Keats) wrote:
Remove a well adhered patch. You will see no indication
of chemical bond formation.
--
Michael Press
Nick L Plate
Of which, ready prepared patches should help to aleviate, although
some think the solution is the solution and do no preperation.
Nick L Plate
No it's just rubber. Plain old rubber. A high shear strength contact
adhesive which may be suitable for booting tyre casings is a synthetic
formulation, I think I have just removed a tub's basetape which had
been manufactured using the synthetic to b0ond the tape to the rubber
on the casing. Definitely stronger than the usual contact bond.
Nick L Plate
wrote:
> On Sun, 26 Apr 2009 04:51:06 -0700 (PDT), spikenett...@earthlink.net
> 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.
>
>
> 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?
What have you?
Tom Keats
Michael Press <rub...@pacbell.net> writes:
> In article <4egvsg...@news.motzarella.org>,
> tkeat...@hotmail.com (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.
Nick L Plate
> 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?
Lower the surface tension by heat or chemical.
> 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.
make 'em wet and jiggle a little. The proximity and movement enables
the cross bonding. They'll come right in the end.
Michael Press
tkeat...@hotmail.com (Tom Keats) wrote:
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
jobst....@stanfordalumni.org
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 Brandt
jobst....@stanfordalumni.org
http://www.madsci.org/posts/archives/1998-05/893193004.Ch.r.html
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.
Jobst Brandt
spiken...@earthlink.net
> >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.
>
>
> 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
Nick L Plate
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.
Nick L Plate
If a thin enough applcation can be made with latex solution, then it
is suitable for patching, particularly if you heat the tube first.
jim beam
if you cut a piece of rubber, how will you see evidence of chemical bond
formation?
jim beam
no shit.
jim beam
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?
Martin Riddle
"Tom Keats" <tomk...@bud.garden.local> wrote in message
news:0p1usg...@news.motzarella.org...
> In article <gstp9b$sif$1...@news.motzarella.org>,
> Tom Sherman <sunsetss000...@yahoo.com> 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?
>>>
> 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
jim beam
dude, heptane is just the solvent. doesn't mean shit about the bonding
ingredients.
Tom Keats
Ablang <ron...@gmail.com> 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
Nick L Plate
> In article <5f32753a-a42b-4d4b-9106-7137778bf...@p6g2000pre.googlegroups.com>,
> Ablang <ron...@gmail.com> 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.
Tom Keats
> dude, heptane is just the solvent. doesn't mean shit 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.
jim beam
ok, you can't read. 'nuff said.
DirtRoadie
> > 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
Tom Keats
jobst....@stanfordalumni.org writes:
> 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
In this discussion, some folks seem to refute that liquid vulcanizing
agents can coexist with rubber cement in the same off-the-shelf
container. There seems to be a lot of semantically induced confusion.
> 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 yet a well-applied patch snuggles right up to its inner tube.
It doesn't just sit there -- it appears to be firmly /pressed/ on,
despite no clamp or vise being used. And that's what piques my
curiosity.
Whatever simply sticks a patch onto a tube can be readily explained.
Heck, anyone can stick a Rice Crispy square onto an inner tube.
I'd just like to know what pushes or pulls a patch so securely
and firmly onto a tube. And I'm talking about naked tubes that
have been patched and then slung over the back of a chair overnight,
without being installed in a tire. That patch is on there like
a suction cup.
jim beam
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?
jim beam
> On Sun, 26 Apr 2009 07:45:56 -0700, jim beam
> <retard...@bad.example.net> wrote:
>
>>> What's a suggested glue for tube on tube patching?
>> 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.
RonSonic
Hey Tom, maybe I can help.
In emergencies I've successfully shortened and rewelded "rubber" belts in things
like tape recorders and turntables using super glue (cyano-acrylate). It works
very nicely. I've read of people healing cuts in tire treads with the stuff as
well.
Has anyone tried the stuff on patches?
Is it perhaps the answer for someone like SJM who, against all advice and the
accumulated experience of every single person in this forum, insists on trying
to use pieces of tube as a patch? Would CA do it?
Tom Keats
Stuff sticking to each other (adhesion) is one thing.
Stuff integrating itself with other stuff (cohesion)
is quite another. Non-chemical cohesion is a particularly
(sorry for the unintended pun) intriguing concept.
It would appear you resent people asking how or why.
It would appear you're axiomatically religous,
and resent inquiry.
That would make you an anti-scientist.
I dare you to consider that.
In the meantime, you're just another tiresome,
officious, bloody know-it-all with nothing of
value to contribute.
Or maybe you do have valuable stuff to contribute,
but you've obfiscated it with your snooty attitude.
So, where were we? Oh yeah. You were criticising
my communication capabilities. Yeah, I often leave
myself open to misconstruement. Oh well.
jim beam
loctite 404 is /specific/ for rubbers. it comes in their o-ring kits.
Tom Keats
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.
Bill Sornson
> loctite 404 is /specific/ for rubbers.
Try telling your S.O. that.
RonSonic
wrote:
>RonSonic wrote:
Good to know. Thanks j.
Martin Riddle
"jim beam" <retard...@bad.example.net> wrote in message
news:vrednWEWnNuMMGjU...@speakeasy.net...
404 dries hard as a rock too.
Cheers
Paul O
> On Sun, 26 Apr 2009 21:08:16 -0700, jim beam
> <retard...@bad.example.net> 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?
>>
>
> 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)
AMuzi
>> 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
>> 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.
Still Just Me wrote:
> 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?
The cement in patch kits is good, Rema cement is usually
sold separately in bike shops next to the patch kits.
"Tech" brand cement, metal 8oz tin, brush-in-lid is
excellent. Tech has route salesman in step vans who visit
auto tire shops, not sure if they have retail outlets.
--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971
Tom Sherman
> [...]
> loctite 404 is /specific/ for rubbers. it comes in their o-ring kits.
>
--
Tom Sherman - 42.435731,-83.985007
LOCAL CACTUS EATS CYCLIST - datakoll
jim beam
give us a fucking break. squeeze some glue onto a piece of plastic,
then walk away and let it dry. like for a day or so, just to be real
certain. what's left? vacuum? or is it dried out pixie boogers - the
secret of any successful tube repair? if the latter tom, maybe, just
maybe, there's more to this glue stuff than you've bothered to let into
that tiny little cranium of yours so far.
jim beam
funny, but family newsgroup buddy.
jim beam
> "jim beam" wrote:
>> [...]
>> loctite 404 is /specific/ for rubbers. it comes in their o-ring kits.
>>
> All types of rubber? Other elastomers?
>
broken fingers tom? can't google "loctite 404 data sheet"?
Tom Sherman
No "jim", I was giving you a chance to show off your knowledge.
jim beam
> "jim beam" wrote:
>> Tom Sherman wrote:
>>> "jim beam" wrote:
>>>> [...]
>>>> loctite 404 is /specific/ for rubbers. it comes in their o-ring kits.
>>>>
>>> All types of rubber? Other elastomers?
>>>
>>
>> broken fingers tom? can't google "loctite 404 data sheet"?
>
> No "jim", I was giving you a chance to show off your knowledge.
>
ok, i'll share. there's this /fab/ web site. it's called
goo-something. i saw some guy use it once. lots of naked chicks
apparently. anyway, where were we?
AMuzi
>> [...]
>> loctite 404 is /specific/ for rubbers. it comes in their o-ring kits.
Tom Sherman wrote:
> All types of rubber? Other elastomers?
http://www.allfasteners.com/Loctite-Quick-Set-404-Industrial-Adhesive--13-Oz-Net-Wt-Bottle-405E20541_p_271.html
"Rubber belts, bumpers and O-rings; metal handles, parts and
wires; plastic nameplates, signs and trim. "
Tom Keats
Paul O <first....@company.com> writes:
> Still Just Me wrote, On 4/27/2009 12:47 PM:
>> On Sun, 26 Apr 2009 21:08:16 -0700, jim beam
>> <retard...@bad.example.net> 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?
d. e.e. cummings appreciado.
anyways, I wish us all ultimately well.
even jim sunbeam, despite his being a
frumpy, miserable ol' grouch with issues,
and possibly, torments.
have a nice day, jim. just please try
to not spoil anybody else's. ya surly
ol' goat, ya.
Tom Keats
Michael Press <rub...@pacbell.net> writes:
> In article <d5t2tg...@news.motzarella.org>,
> tkeat...@hotmail.com (Tom Keats) wrote:
>
>> In article <rubrum-11580C....@news.sf.sbcglobal.net>,
>> Michael Press <rub...@pacbell.net> writes:
>> > In article <4egvsg...@news.motzarella.org>,
>> > tkeat...@hotmail.com (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.
>>
>> 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.
>>
>> 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?
^^^^^^^^^^^^^^^^^^
But exactly ~what~ forces are at work?
That is my question.
We stick a patch on a tube, maybe press it on
a little, leave it overnight, and when we look
at it the next day, the patch is pancaked right
on there as if it had been in a clamp.
I realize the patch isn't chemically integrated
with the inner tube rubber. But it does seem to
be more mechanically squashed onto the tube than
by the thumb pressure that initially installed it
into place. I'm just curious as to what does that.
I'm guessing that as the more volatile stuff in
the cement evaporates, the remaining cement
somehow shrinks, thereby pulling interdigitated
patch & inner tube together. But that's just a
guess on my part, and guessing ain't knowing.
Shrinkage of the cement at least provides an
explanation for the movement necessary for the
process.
I think wet newspaper pages are stuck together by
air pressure and maybe a li'l static electricity
largely introduced by foreign material and dust on
the paper. But I'm probably wrong about that, too.
It would be nice to know what's really going on.
jim beam
oh, i'm very easy to please tom. polite sometimes too. the solution?
stop being an ineducable freakin' looney tune. vacuum tire patches???
how the heck people like you get out of bed in the morning is something
i simply don't understand.
jim beam
you've been told three times now. if you don't get it, you have either
a fundamental education gap somewhere back in junior school, or you're
just too damned dim.
either way, if you can read and still don't understand, just give up
because this stuff is clearly beyond you.
Michael Press
tkeat...@hotmail.com (Tom Keats) wrote:
Induced electric dipole interaction.
> We stick a patch on a tube, maybe press it on
> a little, leave it overnight, and when we look
> at it the next day, the patch is pancaked right
> on there as if it had been in a clamp.
The loss of volatile solvent is so rapid you see
the patch move closer to the tube as the glue volume decreases.
>
> I realize the patch isn't chemically integrated
> with the inner tube rubber. But it does seem to
> be more mechanically squashed onto the tube than
> by the thumb pressure that initially installed it
> into place. I'm just curious as to what does that.
>
> I'm guessing that as the more volatile stuff in
> the cement evaporates, the remaining cement
> somehow shrinks, thereby pulling interdigitated
> patch & inner tube together. But that's just a
> guess on my part, and guessing ain't knowing.
> Shrinkage of the cement at least provides an
> explanation for the movement necessary for the
> process.
Yes.
> I think wet newspaper pages are stuck together by
> air pressure and maybe a li'l static electricity
> largely introduced by foreign material and dust on
> the paper. But I'm probably wrong about that, too.
> It would be nice to know what's really going on.
Electrical forces are what constitute the London and
van der Waals forces previously mentioned. To know
what is really going on do a year of physics; a year
of chemistry; a year of electrodynamics; a year of
thermodynamics and statistical physics---alternatively
a year of physical chemistry; and a couple years of
calculus. MIT puts all their courses complete with
problem sets on the web.
--
Michael Press
Michael Press
tkeat...@hotmail.com (Tom Keats) wrote:
> In article <49F5EE60...@company.com>,
> Paul O <first....@company.com> writes:
> > Still Just Me wrote, On 4/27/2009 12:47 PM:
> >> On Sun, 26 Apr 2009 21:08:16 -0700, jim beam
> >> <retard...@bad.example.net> 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?
>
> d. e.e. cummings appreciado.
No, E.E. Cummings capitalized proper names, except his own.
> anyways, I wish us all ultimately well.
> even jim sunbeam, despite his being a
> frumpy, miserable ol' grouch with issues,
> and possibly, torments.
>
> have a nice day, jim. just please try
> to not spoil anybody else's. ya surly
> ol' goat, ya.
--
Michael Press
Nick L Plate
> On Apr 26, 6:55 pm, jobst.bra...@stanfordalumni.org 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.
I cannot support this for I have had no desire to remove a well
adhered patch. Why?
jim beam
> On Tue, 28 Apr 2009 05:48:46 -0700, jim beam
> <retard...@bad.example.net> wrote:
>
>> you've been told three times now. if you don't get it, you have either
>> a fundamental education gap somewhere back in junior school, or you're
>> just too damned dim.
>
> class in 8th grade?
not materials, reading comprehension. like you apparently. moron.
jim beam
that's not the point - the point is that it's been explained in this
thread. if you want to get into detail, read up on the above, but you
don't need to do that to simply accept the concept of molecular interaction.
jobst....@stanfordalumni.org
>>>> 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
>> access 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.
> I cannot support this for I have had no desire to remove a well
> adhered patch. Why?
Assuming the rider followed good patching procedures, but chose to
ride his freshly patched tube whose patch can lift off radially from
the hole, forming the dome I described, without leaking. Such patches
can become slow leaks but in time become "well adhered", requiring
special means for removal as described.
That is Why!
Jobst Brandt
jim beam
er. jobst, you're contrdicting yourself. one moment you say "the rider
followed good patching procedures", then you say "his freshly patched
tube whose patch can lift off radially from the hole".
if the tube is patched per the manufacturer's procedure, the correct
procedure, patches do not lift. thus, if you experience this problem,
you're not following correct procedure.
did you ever study logic?
Nick L Plate
> tkeats2...@hotmail.com (Tom Keats) considered Sun, 26 Apr 2009
> 17:10:21 -0700 the perfect time to write:
>
>
>
> >In article <rubrum-11580C.16183426042...@news.sf.sbcglobal.net>,
> > Michael Press <rub...@pacbell.net> writes:
> >> In article <4egvsg.4e3...@news.motzarella.org>,
> The preparation with rubber cement can be visualised as the process
> which makes the fibres on one side curl up into little hooks.
The answer: "Patching a tube is like Velcro"
Nick L Plate
I'm getting splinters under my nails here.
Michael Press
Still Just Me <stilln...@stillnodomains.com> wrote:
> On Tue, 28 Apr 2009 11:56:18 -0700, Michael Press <rub...@pacbell.net>
> wrote:
>
> >Electrical forces are what constitute the London and
> >van der Waals forces previously mentioned. To know
> >what is really going on do a year of physics; a year
> >of chemistry; a year of electrodynamics; a year of
> >thermodynamics and statistical physics---alternatively
> >a year of physical chemistry; and a couple years of
> >calculus. MIT puts all their courses complete with
> >problem sets on the web.
>
> All of which, as jb noted, are taught in Jr. High.
Indeed, I slept through it.
--
Michael Press
jim beam
> In article <4ceav4tqlvo4icr58...@4ax.com>,
> 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.
>
>
> Thank you.
>
>
> cheers,
> Tom
>
thank fuck.
dgk
<tj-...@blueyonder.co.uk> wrote:
>On 29 Apr, 05:08, jobst.bra...@stanfordalumni.org wrote:
>> Trevor Jeffrey wrote:
>> >>>> Remove a well adhered patch. �ｿｽYou will see no indication of
>> >>>> chemical bond formation.
>> >>> I find a well adhered patch not removable without
>> >>> heating. �ｿｽHeating affects the REMA patch orange rubber more than
>> >>> the tube rubber so they separate with careful pulling. �ｿｽ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
>> >> access to the tube/patch interface. �ｿｽOnce that is accomplished the
>> >> rest is easy using a slow "peeling" technique in conjunction with
>> >> more solvent (think "cotton swab"). �ｿｽ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.
>> > I cannot support this for I have had no desire to remove a well
>> > adhered patch. �ｿｽWhy?
>>
>> Assuming the rider followed good patching procedures, but chose to
>> ride his freshly patched tube whose patch can lift off radially from
>> the hole, forming the dome I described, without leaking. �ｿｽSuch patches
>> can become slow leaks but in time become "well adhered", requiring
>> special means for removal as described.
>>
>> That is Why!
>
>I'm getting splinters under my nails here.
I think it's time to buy a new tube.
Tom Keats
Michael Press <rub...@pacbell.net> writes:
Maybe one of these days I'll get a round tuit.
Just need a refresher for the Math (funny, how
quickly that stuff falls outa one's brain when
you don't use it every day.) As for the rest,
I'd just need the books & info. Screw the
accreditation.
All that studying could really put a hurt onto
one's riding time.
So, thank you for your kind patience and
willingness to help people understand stuff.
You are appreciated.
Michael Press
tkeat...@hotmail.com (Tom Keats) wrote:
You are welcome.
--
Michael Press