Stronger rubber cement?

On Wed, 4 Jan 2017 12:29:31 -0500, Frank Krygowski
wrote:

On 1/3/2017 11:23 PM, Jeff Liebermann wrote:


Contact cement. It's a neoprene rubber based goo that remains fairly
flexible if applied in a very thin layer. Smear some on both the tire
and the patch, let air dry for at least 10 minutes (longer is better),
and stick together with a little compression pressure. I've used a
roller, two blocks of wood and a C-clamp, and beating on the sandwich
with a hammer. They all work.

I generally change tubes on the road, then patch the leaking tube at home.

Same here. However, I don't ride enough to get very many flats. The
bane of my life are leaking tubes. Even brand new tubes (Nashbar's
cheapest) tend to leak. I've done a bubble test and usually find pin
holes at random location. It's not worth the effort doing the full
patch job for a pin hole, so I just stretch the tube so I can see the
hole, fill it with rubber cement, wipe off the excess, and let it dry.
That works, until a new pinhole appears.

Then, there are the leaky tire valves, usually because I've lost the
caps and the valve is full of dirt. Sigh.

At home, the first step is to clamp a 1" dowel in my bench vise and
drape the tube over it with the leak facing upwards. That's the support
while I scuff the tube using ordinary sandpaper. I find the cylindrical
surface makes it easier to scuff thoroughly.

Good idea. Thanks.

With the inner tube still hanging from the dowel, I then apply cement,
let it dry a bit and apply the patch. Next I take another dowel held
perpendicular to the one in the vise, and roll back and forth over the
patch to apply pressure. The contact area is thus smaller and the
pressure on the patch greater. I don't believe I've ever had a patch
fail after being applied this way.

Yep. Much easier to fix a tire on the bench than on the road. What
drove me nuts and inspired me to carry spare tubes is having more than
one hole in the tube. I would assume that the leak I found is the
only one, patch it, and after putting everything back together, find
the tube still leaking air. After patching one tube 4 times on the
road, and running out of patches, I decided that life is too short to
waste on this exercise.

Flame vulcanizing tire patch:
https://www.youtube.com/watch?v=ennV0BVFZVw
I did that during the 1960's when I worked in a gas station.


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

Joerg wrote:
:On 2017-01-03 18:47, David Scheidt wrote:
: John B. wrote:
: :On Tue, 03 Jan 2017 17:04:40 -0800, Joerg
: :wrote:
:
: :Gentlemen,
: :
: :Is there something stronger than the usual rubber cement in the patch
: :kits? Ideally something that won't dry out so fast or where multiple
: :cheap small tubes are available.
: :
: :The reason is that I sometimes have larger holes from side wall
: :blow-outs. Not inch-long gashes but one or two tenths of an inch long.
: :The tubes I use are super thick and, therefore, expensive. $15-20 each
: :and that's not something to be thrown out lightly. Instead of the li'l
: :REMA patches I need to use thicker rubber from an older sacrified tube
: :but this has to be vulcanized/cemented really well.
:
: :My LBS usually has small sealed tubes of glue. When I see them I buy
: :four or five and when I open a sealed tube, in the kit on the bike, I
: :replace it with another sealed one as find the glue has dried up is
: :not quite so much of a catastrophe at home :-)
:
: :Or you might try contact cement what I suspect is what is in the usual
: :tire patching kit.
:
: :By the way, "vulcanizing" implies the use of heat, and sulphur, and I
:
: Vulcanizing may have the connotation of involving heat, but it's a chemical
: reaction, which results in the sulphur in the rubber becoming
: crosslinked.


:That's how I also remember it.


: ... Patches, at least the good ones such as Rema and park,
: are a multi-layered assembly. The top layers are for strength, the
: bottom (closest to the tube) consists of unvulcanized rubber, mixed
: with a vulcanizing ultra-accelerator (there are a number of zinc
: thiols that are suitable, which ones are used are trade secrets. ZDDP
: is typical, though). vulcanizing cement consists of a unvulcanized
: rubber particles, a solvent to carry them, and a vulcanizing
: activator. Cyclohexylamine is common, but there are others that will
: work, and are less toxic. The activator reacts with the zinc thiol,
: and causes the patch, the rubber in the cement, and the surface of
: tube to become vulcanized. There's not much free sulphur in the tube,
: because it's vulcanized, which is one of the reasons that it's
: important to properly scarify the tube surface before patching; it
: greatly increases the surface area of the patch. The reaction is not
: instant, but it happens pretty fast at room temperature, and
: continues for some time, until all the sulphur available has linke.d
:

:Ever since I began using REMA patches and the cement that comes with
:them my result were less stellar than in Europe with the classic kits.
:Those contain much thicker patches that looked like round chunks of
:tube, sometimes slightly beveled. Can't find those here in the US.

Rema patches in action:
https://scontent.ford4-1.fna.fbcdn.n...bb&oe=58E69CCC

https://scontent.ford4-1.fna.fbcdn.n...9c&oe=58E45D94

That tube is still in service, two years later.


:The question is why would be the good ones to buy?

I use rema f1, which are round and 25 mm in diameter. Box of 100
costs ~20 bucks. A half pint bottle of vulcanizing flouid, which will
do hundreds of patches, and last for years (mine has been in my dsk
for five years) costs ~$10 at an auto parts store (very expensive to
ship, buy local.).


--
sig 38

Jeff Liebermann writes:

On Wed, 04 Jan 2017 07:27:48 -0800, Joerg
wrote:

I'll look into contact cement. Gene also suggested that. Cost is not so
much an issue but shelf life after opening is. The usual rubber cement
is toast only a few months after opening.

I've had the same experience. The problem with the leaking bottles
and tubes seems to be related to heat. My squeeze tube of contact
cement doesn't last very long after it's used once, so I'm not sure
that looking for a better glue is the right answer. A better way to
prevent outgassing seems to be a better approach. As David Scheidt
suggests, buying the rubber cement or whatever in a can lasts much
longer. I keep my can inside a plastic Ziploc bag, which seems to
help. I've considered putting it inside a glass jar, and pressurizing
the jar to above the vapor pressure of the solvent to limit loss by
evaporation. I've done this with some chemicals and drugs, but never
tried it with glue.

I can't see how that would work -- the partial pressure of the solvent
inside and outside are the only variables that matter. Higher total
pressure should affect diffusion to the outside of the inner container
very little. An outer bag or jar works by concentrating the escaped
solvent, so it's important to keep the volume low.

--

On 1/4/2017 12:40 PM, Joerg wrote:
On 2017-01-04 09:14, Frank Krygowski wrote:
On 1/4/2017 10:17 AM, Joerg wrote:

Ever since I began using REMA patches and the cement that comes with
them my result were less stellar than in Europe with the classic kits.
Those contain much thicker patches that looked like round chunks of
tube, sometimes slightly beveled. Can't find those here in the US.

Currently I have two tubes of the thick expensive kinds where REMA
patches partially came off after test-inflating outside the tire.
Despite being very diligent with sanding and applying.

I don't see any value to test inflating a freshly patched tube outside
the tire. You're imparting stresses that the patch-to-tube bond will
never see in its normal working life, and it will be difficult for that
immature bond to resist them.


With Gatorskin tires and shallow rims it is a must.

Why? Use the proper patching technique (which is not difficult),
reassemble tire and tube then ride. It's silly to subject the fresh
patch to irrelevant stresses.

I only did this once
and never again: Fixed a hole on the side of a tube, mounted a new
Gatorskin. Those can take over an hour of wrestling to get the bead
over. Pumped it up. Next morning on the day where I wanted to ride ...
flat :-(


Patches that have completely cured stand up to being inflate outside the
tire, in my experience. I've never had one fail.


I did.

I suspect all of us have botched a patch repair at least once. That
should motivate you to use more care and better technique, nothing more.
Don't throw the baby out with the bath water.

The last failed patch job I remember was in 1976, I think. The end
result (pumping an unrepairable tube every five miles, while on a loaded
tour) inspired me to do the subsequent ones more carefully. And to
always carry a spare tube.


--
- Frank Krygowski

On 2017-01-04 08:12, David Scheidt wrote:
Joerg wrote:
:On 2017-01-04 00:01, Dennis Davis wrote:
: In article ,
: Joerg wrote:
: Gentlemen,
:
: Is there something stronger than the usual rubber cement in the
: patch kits? Ideally something that won't dry out so fast or where
: multiple cheap small tubes are available.
:
: The reason is that I sometimes have larger holes from side wall
: blow-outs. Not inch-long gashes but one or two tenths of an
: inch long. The tubes I use are super thick and, therefore,
: expensive. $15-20 each and that's not something to be thrown
: out lightly. Instead of the li'l REMA patches I need to use
: thicker rubber from an older sacrified tube but this has to be
: vulcanized/cemented really well.
:
: The small REMA patches are some 15mm in diameter. Larger sizes
: exist. I believe the next size up is 25mm in diameter and the oval
: REMA patches are available. An ebay search should throw up what's
: available by mail order.
:
: Same for the the REMA rubber cement. It comes in different size
: tubes, including the small ones you mention. Again an Internet
: search should show what's available.
:
: I don't usually have problems using REMA patches & glue. However
: puncture repairing technique can be as contentious as chain cleaning
: and lubrication advice. I'm going to keep my head down :-)
:

:I have used the big oblong REMAs as well and that's the ones thah failed
:the most on sidewalls. They are rather thin.

Use a tire patch or boot, not one for an inner tube. Totally
different problems, totally different solutions.


I meant for fixing the tube at the location where the side wall blew. I
never attempt to repair the tire because when a side wall went it's
toast. Usually several strands of material are shredded afterwards.

The worst one was a literal explosion in the wilderness but that left an
unfixable huge hole in the tube. It also triggered a micro-stampede of
five cows.

--
Regards, Joerg

http://www.analogconsultants.com/

On 2017-01-04 10:56, Frank Krygowski wrote:
On 1/4/2017 12:40 PM, Joerg wrote:
On 2017-01-04 09:14, Frank Krygowski wrote:
On 1/4/2017 10:17 AM, Joerg wrote:

Ever since I began using REMA patches and the cement that comes with
them my result were less stellar than in Europe with the classic kits.
Those contain much thicker patches that looked like round chunks of
tube, sometimes slightly beveled. Can't find those here in the US.

Currently I have two tubes of the thick expensive kinds where REMA
patches partially came off after test-inflating outside the tire.
Despite being very diligent with sanding and applying.

I don't see any value to test inflating a freshly patched tube outside
the tire. You're imparting stresses that the patch-to-tube bond will
never see in its normal working life, and it will be difficult for that
immature bond to resist them.


With Gatorskin tires and shallow rims it is a must.

Why? Use the proper patching technique (which is not difficult),
reassemble tire and tube then ride. It's silly to subject the fresh
patch to irrelevant stresses.


You never know if that hole was the only one. That's the problem. I
don't want to have to do the bucket of water thing every time. Certainly
not during a drought phase.


I only did this once
and never again: Fixed a hole on the side of a tube, mounted a new
Gatorskin. Those can take over an hour of wrestling to get the bead
over. Pumped it up. Next morning on the day where I wanted to ride ...
flat :-(


Patches that have completely cured stand up to being inflate outside the
tire, in my experience. I've never had one fail.


I did.

I suspect all of us have botched a patch repair at least once. That
should motivate you to use more care and better technique, nothing more.
Don't throw the baby out with the bath water.

The last failed patch job I remember was in 1976, I think. The end
result (pumping an unrepairable tube every five miles, while on a loaded
tour) inspired me to do the subsequent ones more carefully. And to
always carry a spare tube.


I always carry a spare tube. So far only used for other riders. To my
surprise we even made it home after I crammed my 29" tube into a rider's
26" tire. It was either that or hoofing it.

--
Regards, Joerg

http://www.analogconsultants.com/

Joerg wrote:

:I meant for fixing the tube at the location where the side wall blew. I
:never attempt to repair the tire because when a side wall went it's
:toast. Usually several strands of material are shredded afterwards.

:The worst one was a literal explosion in the wilderness but that left an
:unfixable huge hole in the tube. It also triggered a micro-stampede of
:five cows.

Take a look aat the pictures I linked to else thread. Rema patches
work fine, properly applied. That tube was mounted wrong, pinched
between the tire and the wheel, and exploded (it sounded like a gun
shot) while hanging on the wall at work. (Not my bike nor mounting
job. I just fix tubes, because I can.



--
sig 87

On 2017-01-04 10:31, David Scheidt wrote:
Joerg wrote:
:On 2017-01-03 18:47, David Scheidt wrote:
: John B. wrote:
: :On Tue, 03 Jan 2017 17:04:40 -0800, Joerg
: :wrote:
:
: :Gentlemen,
: :
: :Is there something stronger than the usual rubber cement in the patch
: :kits? Ideally something that won't dry out so fast or where multiple
: :cheap small tubes are available.
: :
: :The reason is that I sometimes have larger holes from side wall
: :blow-outs. Not inch-long gashes but one or two tenths of an inch long.
: :The tubes I use are super thick and, therefore, expensive. $15-20 each
: :and that's not something to be thrown out lightly. Instead of the li'l
: :REMA patches I need to use thicker rubber from an older sacrified tube
: :but this has to be vulcanized/cemented really well.
:
: :My LBS usually has small sealed tubes of glue. When I see them I buy
: :four or five and when I open a sealed tube, in the kit on the bike, I
: :replace it with another sealed one as find the glue has dried up is
: :not quite so much of a catastrophe at home :-)
:
: :Or you might try contact cement what I suspect is what is in the usual
: :tire patching kit.
:
: :By the way, "vulcanizing" implies the use of heat, and sulphur, and I
:
: Vulcanizing may have the connotation of involving heat, but it's a chemical
: reaction, which results in the sulphur in the rubber becoming
: crosslinked.


:That's how I also remember it.


: ... Patches, at least the good ones such as Rema and park,
: are a multi-layered assembly. The top layers are for strength, the
: bottom (closest to the tube) consists of unvulcanized rubber, mixed
: with a vulcanizing ultra-accelerator (there are a number of zinc
: thiols that are suitable, which ones are used are trade secrets. ZDDP
: is typical, though). vulcanizing cement consists of a unvulcanized
: rubber particles, a solvent to carry them, and a vulcanizing
: activator. Cyclohexylamine is common, but there are others that will
: work, and are less toxic. The activator reacts with the zinc thiol,
: and causes the patch, the rubber in the cement, and the surface of
: tube to become vulcanized. There's not much free sulphur in the tube,
: because it's vulcanized, which is one of the reasons that it's
: important to properly scarify the tube surface before patching; it
: greatly increases the surface area of the patch. The reaction is not
: instant, but it happens pretty fast at room temperature, and
: continues for some time, until all the sulphur available has linke.d
:

:Ever since I began using REMA patches and the cement that comes with
:them my result were less stellar than in Europe with the classic kits.
:Those contain much thicker patches that looked like round chunks of
:tube, sometimes slightly beveled. Can't find those here in the US.

Rema patches in action:
https://scontent.ford4-1.fna.fbcdn.n...bb&oe=58E69CCC

https://scontent.ford4-1.fna.fbcdn.n...9c&oe=58E45D94

That tube is still in service, two years later.


Impressive. I wouldn't even have tried to repair that one.

One significant difference is that my tubes are much thicker in their
walls. 3mm on the road bike and 4mm on the MTB. So the tube material is
many times thicker than REMA patches.


:The question is why would be the good ones to buy?

I use rema f1, which are round and 25 mm in diameter. Box of 100
costs ~20 bucks. A half pint bottle of vulcanizing flouid, which will
do hundreds of patches, and last for years (mine has been in my dsk
for five years) costs ~$10 at an auto parts store (very expensive to
ship, buy local.).


Looks like it ships free if you get past $49 with all the other stuff to
be ordered:

https://www.amazon.com/STEELMAN-G101.../dp/B00NBTGCLS

The "Slime" brand is cheaper. Do you think the one below works as well?
I was not impressed with their self-healing tubes but this seems to be
other stuff.

https://www.amazon.com/Slime-1050-Ru.../dp/B003V9UU66

What we do is keep a tab on things that are needed elsewhere. Such as
espresso or (for bike riding) Ultima Replenisher electrolyte powder.
That is then used top fill orders beyond the $49 free-ship barrier.

Also, I'd like to cement on real (thicker) tube material instead of REMA
patches. Don't see a reason why this shouldn't be possible.

--
Regards, Joerg

http://www.analogconsultants.com/

On 1/4/2017 2:04 PM, Joerg wrote:
On 2017-01-04 10:56, Frank Krygowski wrote:
On 1/4/2017 12:40 PM, Joerg wrote:
On 2017-01-04 09:14, Frank Krygowski wrote:
On 1/4/2017 10:17 AM, Joerg wrote:

Ever since I began using REMA patches and the cement that comes with
them my result were less stellar than in Europe with the classic kits.
Those contain much thicker patches that looked like round chunks of
tube, sometimes slightly beveled. Can't find those here in the US.

Currently I have two tubes of the thick expensive kinds where REMA
patches partially came off after test-inflating outside the tire.
Despite being very diligent with sanding and applying.

I don't see any value to test inflating a freshly patched tube outside
the tire. You're imparting stresses that the patch-to-tube bond will
never see in its normal working life, and it will be difficult for that
immature bond to resist them.


With Gatorskin tires and shallow rims it is a must.

Why? Use the proper patching technique (which is not difficult),
reassemble tire and tube then ride. It's silly to subject the fresh
patch to irrelevant stresses.


You never know if that hole was the only one. That's the problem. I
don't want to have to do the bucket of water thing every time. Certainly
not during a drought phase.

I check at the beginning, before patching. It's not difficult.

Well, it's not been difficult for me. I know things are often much
worse for you.


--
- Frank Krygowski

Joerg wrote:
: :them my result were less stellar than in Europe with the classic kits.
: :Those contain much thicker patches that looked like round chunks of
: :tube, sometimes slightly beveled. Can't find those here in the US.
:
: Rema patches in action:
: https://scontent.ford4-1.fna.fbcdn.n...bb&oe=58E69CCC
:
: https://scontent.ford4-1.fna.fbcdn.n...9c&oe=58E45D94
:
: That tube is still in service, two years later.
:

:Impressive. I wouldn't even have tried to repair that one.

:One significant difference is that my tubes are much thicker in their
:walls. 3mm on the road bike and 4mm on the MTB. So the tube material is
:many times thicker than REMA patches.

:
: :The question is why would be the good ones to buy?
:
: I use rema f1, which are round and 25 mm in diameter. Box of 100
: costs ~20 bucks. A half pint bottle of vulcanizing flouid, which will
: do hundreds of patches, and last for years (mine has been in my dsk
: for five years) costs ~$10 at an auto parts store (very expensive to
: ship, buy local.).
:


:The "Slime" brand is cheaper. Do you think the one below works as well?
:I was not impressed with their self-healing tubes but this seems to be
ther stuff.

:https://www.amazon.com/Slime-1050-Ru.../dp/B003V9UU66

That's what's in my desk at work. Works fine.

:Also, I'd like to cement on real (thicker) tube material instead of REMA
atches. Don't see a reason why this shouldn't be possible.

There's a really good one: The working surface of a patch is made of
unvulcanized rubber. A tube is vulcanized. With vulcanized rubber on
both sides, there will only be weak cross-linking, and it won't be
good bond. Go ahead and try it, but expect failure. Repair units
exist for a reason.

--
sig 125