Patches that fail



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S

Squid-In-Traini

Guest
I used a couple of the black-top, orange-bottom patches recently, and two were to fix tube
failures near the valve (the junction between valve rubber and tube rubber). These holes were
somewhat large in comparison to a thorn, but were they too big for the patch? (the patches were
rather large in comparison to the hole) My big mistake was not waiting overnight to try the
patches. Is it feasible to treat small blow-out type tube failures with patches? I'm not talking
about the huge explosive ones that rip the tube in a starburst pattern... just the small
psssssssst-type ones at the valve stem.

Yes, I'm seating my tubes in the tire before I inflate...

TIA!
--
Phil, Squid-in-Training
 
G

GearóId Ó Laoi

Guest
I'd fix anything if in the mood EXCEPT punctures at valve stem. I don't think it's worth trying.

Do you get the tube really matte?

I use a grinding head on a drill.
 
J

Jobst Brandt

Guest
Phil 'cutsie-pie' writes:

> I used a couple of the black-top, orange-bottom patches recently, and two were to fix tube
> failures near the valve (the junction between valve rubber and tube rubber). These holes were
> somewhat large in comparison to a thorn, but were they too big for the patch? (the patches were
> rather large in comparison to the hole) My big mistake was not waiting overnight to try the
> patches. Is it feasible to treat small blow-out type tube failures with patches? I'm not talking
> about the huge explosive ones that rip the tube in a starburst pattern... just the small
> psssssssst-type ones at the valve stem.

> Yes, I'm seating my tubes in the tire before I inflate...

Try curing the patch before you inflate... a day or so in a warm atmosphere is best.

http://draco.acs.uci.edu/rbfaq/FAQ/8b.1.html

Jobst Brandt [email protected] Palo Alto CA
 
D

Doug Goncz

Guest
>I used a couple of the black-top, orange-bottom patches recently, and two were to fix tube failures
>near the valve (the junction between valve rubber and tube rubber).

How the heck did you get the patch wrapped around the valve?

Was it the junction between thicker rubber near the valve, and thinner rubber, say, an inch away?

I carry a spare tube, and patch at home, using acetone to remove the mold release on the rubber, and
after application, rolling the patch with a screen door spline rolling tool to really stick it on
there. Then let it sit a while.

Yours,

Doug Goncz, Replikon Research, Seven Corners, VA (truncate pee dot mil antispam for mail)
http://users.aol.com/DGoncz http://groups.google.com/groups?as_q=DGoncz "Function, Funding, Form,
Fit, and Finish"
 
A

A Muzi

Guest
"Phil, Squid-in-Training" <[email protected]> wrote in message
news:G%[email protected]...
> I used a couple of the black-top, orange-bottom patches recently, and two were to fix tube
> failures near the valve (the junction between valve
rubber
> and tube rubber). These holes were somewhat large in comparison to a
thorn,
> but were they too big for the patch? (the patches were rather large in comparison to the hole) My
> big mistake was not waiting overnight to try
the
> patches. Is it feasible to treat small blow-out type tube failures with patches? I'm not talking
> about the huge explosive ones that rip the tube
in
> a starburst pattern... just the small psssssssst-type ones at the valve stem.
>
> Yes, I'm seating my tubes in the tire before I inflate...

I remember someone else here last week making a comment about "waiting overnight" before using
a patched tube. I do not feel that is a reasonable thing - either you have patched it well or
you have not.

Although I do not customarily patch nowadays, when we did it was a dozen or more a day every day and
patches do indeed hold just fine when mounted immediately after patching. One should not be hasty
about slapping a patch on wet cement but that's a matter of thirty seconds, not 24 hours.

Anyone else care to comment here?
--
Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971
 
S

Scic

Guest
>From: "A Muzi"

>Anyone else care to comment here?

Never had a patch fail either. But I do wait a full 5 min before applying the patch, then roll it
on, rather than just laying it on over the hole.

I would like to find smaller diameter round patches. The "tour/touring" Rema patches are wider than
my 20-25c tubes. I'm guessing that their "sport" kit, which shows a road bike in the cover, has
smaller patches but none of the shops I visit have them. IIRC, these had yellow feathered edges.

Sig Chicago
 
P

Paul Southworth

Guest
In article <[email protected]>, A Muzi <[email protected]> wrote:
>I remember someone else here last week making a comment about "waiting overnight" before using a
>patched tube. I do not feel that is a reasonable thing - either you have patched it well or you
>have not.
>
>Although I do not customarily patch nowadays, when we did it was a dozen or more a day every day
>and patches do indeed hold just fine when mounted immediately after patching. One should not be
>hasty about slapping a patch on wet cement but that's a matter of thirty seconds, not 24 hours.
>
> Anyone else care to comment here?

I don't wait. Never seemed like that caused a problem. Seems like if you've done it properly it
works immediately.
 
J

Jobst Brandt

Guest
Andrew Muzi writes:

> I remember someone else here last week making a comment about "waiting overnight" before using a
> patched tube. I do not feel that is a reasonable thing - either you have patched it well or you
> have not.

Not so. I think that in among the patches you have put in place, you must have had to pull one off
again and reposition or replace it for one reason or another. The removal is easy shortly after
applying the patch but is practically impossible a day later. Somewhere in between there, the patch
is secure enough that it cannot lift of from use.

> Although I do not customarily patch nowadays, when we did it was a dozen or more a day every day
> and patches do indeed hold just fine when mounted immediately after patching. One should not be
> hasty about slapping a patch on wet cement but that's a matter of thirty seconds, not 24 hours.

How do you know? I made the test often enough to know that your experience is not entirely correct.
The belated partially leaky patch is well and alive among on-the-road-patches. When you get ready to
throw a tube away, cut through some of its patches with shears and note how much of the patch has
separated. This is apparent because at the middle of the patch, around the hole, it was not secure
so the area is filled with talcum from within the tube.

> Anyone else care to comment here?

You must have seen the FAQ item describing this:

http://draco.acs.uci.edu/rbfaq/FAQ/8b.1.html

Jobst Brandt [email protected] Palo Alto CA
 
J

Jobst Brandt

Guest
nospam writes shyly:

>>Anyone else care to comment here?

> Never had a patch fail either. But I do wait a full 5 min before applying the patch, then roll it
> on, rather than just laying it on over the hole.

That's cute. Who do you think patches by "just laying it on over the hole" and how do you visualize
someone doing so?

> I would like to find smaller diameter round patches. The "tour/touring" Rema patches are wider
> than my 20-25c tubes. I'm guessing that their "sport" kit, which shows a road bike in the
> cover, has smaller patches but none of the shops I visit have them. IIRC, these had yellow
> feathered edges.

Rema makes all sorts of patches, most of which local distributors don't carry unless you order them.
For instance:

http://www.rema-tiptop.de/Automotive/Deutsch/Kataloge/katanzeige_frameset.php?seite=4,5,6,7,8,9,10,-
11&katalog=RRD

Click on "Seite 1" "Seite 2" etc.

The main web site is currently not available but this one shows larger and smaller patches that
the usual.

Jobst Brandt [email protected] Palo Alto CA
 
P

Phil

Guest
> How the heck did you get the patch wrapped around the valve?

I cut the patch a couple mm at the end that wrapped around the valve.

> Was it the junction between thicker rubber near the valve, and thinner rubber, say, an inch away?

Yep... the junctions on either (longitudinal) side of the tube always seem to get stretched out...

Phil, Squid-in-Training
 
R

Richard Brockie

Guest
[email protected] wrote:
>Rema makes all sorts of patches, most of which local distributors don't carry unless you order
>them. For instance:

Whilst I was on a tram in Amsterdam last year I was interested to notice that the rubber concertina
at the carriage articuation had been patched with a massive (compared to a bicycle tube patch) Rema
patch, roughly 30 cm long.

--
R.

<> Richard Brockie "Categorical statements <> The tall blond one. always cause trouble." <>
[email protected]
 
D

David Damerell

Guest
A Muzi <[email protected]> wrote:
>I remember someone else here last week making a comment about "waiting overnight" before using a
>patched tube. I do not feel that is a reasonable thing - either you have patched it well or you
>have not.

But when I want to know which, I leave it out overnight with some air in it - obviously this doesn't
create total certainty because of the much higher pressure inside a tyre, but it acts as a sanity
check against basic errors.
--
David Damerell <[email protected]> flcl?
 
D

David Damerell

Guest
<[email protected]> wrote:
>nospam writes shyly:
>>Never had a patch fail either. But I do wait a full 5 min before applying the patch, then roll it
>>on, rather than just laying it on over the hole.
>That's cute. Who do you think patches by "just laying it on over the hole" and how do you visualize
>someone doing so?

I have, more than once, rescued someone from the consequences of inept patch application and had an
opportunity to view this technique (where the patch is just brought into contact with the surface as
if it were a piece of sellotape) in use.
--
David Damerell <[email protected]> flcl?
 
G

Gary Young

Guest
[email protected] (Scic) wrote:
> I would like to find smaller diameter round patches. The "tour/touring" Rema patches are wider
> than my 20-25c tubes. I'm guessing that their "sport" kit, which shows a road bike in the
> cover, has smaller patches but none of the shops I visit have them. IIRC, these had yellow
> feathered edges.

The sport kit does have 20mm patches, but I don't think they're feathered. Innovations in
Cycling also makes 20mm patches. They seem to be just as good as the Rema and may even be
rebranded Rema patches.

You can get Innovations patches at 10 for a dollar from Loose Screws:

<http://www.loosescrews.com/index.cgi?d=single&c=Tire/Tube&sc=Repair&tc=&item_id=15-028-030&id=725-
996127049>

Or 100 for $17.95 from Bike Tools Etc.:

<http://www.biketoolsetc.com/index.cgi?id=632344575732&d=single&c=Tire%20Tube&sc=Repair%20Kits%20an-
d%20Supplies&tc=Patches&item_id=IN-9028>

Rivendell has even smaller patches from Velox:

<http://www.rivendellbicycles.com/webalog/tires_tubes/10048.html>

The blue edges are so eye-catching I almost bought a bunch, but the price is higher than for the
Innovations patches -- $3 for 10. They're billed as 15mm, but are only slightly smaller than the
Innovations patches, so I suspect one or the other is fudging the measurement a bit.
 
J

Jay Beattie

Guest
"A Muzi" <[email protected]> wrote in message news:[email protected]...
> "Phil, Squid-in-Training" <[email protected]> wrote in message
> news:G%[email protected]...
> > I used a couple of the black-top, orange-bottom patches recently,
and two
> > were to fix tube failures near the valve (the junction between valve
> rubber
> > and tube rubber). These holes were somewhat large in comparison to
a
> thorn,
> > but were they too big for the patch? (the patches were rather large
in
> > comparison to the hole) My big mistake was not waiting overnight to
try
> the
> > patches. Is it feasible to treat small blow-out type tube failures
with
> > patches? I'm not talking about the huge explosive ones that rip the
tube
> in
> > a starburst pattern... just the small psssssssst-type ones at the
valve
> > stem.
> >
> > Yes, I'm seating my tubes in the tire before I inflate...
>
> I remember someone else here last week making a comment about "waiting overnight" before using a
> patched tube. I do not feel that is a
reasonable
> thing - either you have patched it well or you have not.
>
> Although I do not customarily patch nowadays, when we did it was a
dozen or
> more a day every day and patches do indeed hold just fine when mounted immediately after patching.
> One should not be hasty about slapping a
patch
> on wet cement but that's a matter of thirty seconds, not 24 hours.
>
> Anyone else care to comment here?

Some brands are more difficult than others to patch. Michelin must use a particularly slick rubber
compound or "thick" mold release because it takes a lot more sanding and more drying time to get a
patch to stick. With some tubes, I can get a good, strong patch with less than a minute of drying
time and little sanding. This is usually the case with the cheap, generic tubes. -- Jay Beattie.
 
J

Jobst Brandt

Guest
Jay Beattie writes:

> Some brands are more difficult than others to patch. Michelin must use a particularly slick rubber
> compound or "thick" mold release because it takes a lot more sanding and more drying time to get a
> patch to stick.

I don't understand. If you sand the surface to a matte finish and apply the patch, what makes this
more difficult? Drying time is not affected by tube material, only by how thick the glue is applied.

> With some tubes, I can get a good, strong patch with less than a minute of drying time and little
> sanding. This is usually the case with the cheap, generic tubes.

How do you determine that you get a "strong patch" in contrast to other tubes? This sounds like
black magic to me. Xplain.

Jobst Brandt [email protected] Palo Alto CA
 
J

Jay Beattie

Guest
<[email protected]> wrote in message news:[email protected]...
> Jay Beattie writes:
>
> > Some brands are more difficult than others to patch. Michelin must use a particularly slick
> > rubber compound or "thick" mold release because it takes a lot more sanding and more drying time
> > to get a patch to stick.
>
> I don't understand. If you sand the surface to a matte finish and apply the patch, what makes this
> more difficult? Drying time is not affected by tube material, only by how thick the glue is
> applied.

>
> > With some tubes, I can get a good, strong patch with less than a minute of drying time and
> > little sanding. This is usually the case with the cheap, generic tubes.
>
> How do you determine that you get a "strong patch" in contrast to
other
> tubes? This sounds like black magic to me. Xplain.

For me, a good strong patch is one that does not pull-away at the edges when the tube is inflated
outside the tire and which cannot be picked off like a piece of Silly Putty. On some tubes, I can
sand like crazy, put on a coat of glue, let it dry, apply the patch -- and it simply does not stick
well. I use Camel or Rema vulcanizing solution (canned) and Rema patches. As for drying time, what I
am getting at is that some patches will stick well with very little drying time on some tubes. Other
tubes require longer, more complete drying to get good adhesion. I wait a longer time before
applying the patch and before inflating the tube outside the tire. Maybe this is voo-doo or the
patch placebo effect -- or I could be mistaking cause and effect, but this does reflect my
experience with certain tube brands. -- Jay Beattie.
 
A

A Muzi

Guest
-snip patches-

"Jay Beattie" <[email protected]> wrote in message news:[email protected]...
> Some brands are more difficult than others to patch. Michelin must use a particularly slick rubber
> compound or "thick" mold release because it takes a lot more sanding and more drying time to get a
> patch to stick. With some tubes, I can get a good, strong patch with less than a minute of drying
> time and little sanding. This is usually the case with the cheap, generic tubes. -- Jay Beattie.

Back to the subject, I'll admit that Jobst's argument sounds good (even though I have no evidence of
it). Unfortunately I'll probably never get to test that. We do not patch any longer, as a tube
hasn't changed price in the thirty years I've been in the business but skilled mechanics now cost
more than the $1 per hour they once did.

In commercial practice we don't (didn't) scrape. We used Tech brand patch cleaner ( contains
trichlor and xylene, IIRC) It leaves a dull matte finish that's devoid of wax, oils, etc.

For a striking demonstration, after you've scraped an injury, wipe it thoroughly with some volatile
solvent like tape head cleaner on a cloth. A significant amount of crud comes off on the wiper. That
stuff ( or much of it anyway ) is in the way of a good bond between patch and tube).

--
Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971
 
J

John Albergo

Guest
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Phil wrote:

>>How the heck did you get the patch wrapped around the valve?
>>
>>
>
>I cut the patch a couple mm at the end that wrapped around the valve.
>
>
>
>>Was it the junction between thicker rubber near the valve, and thinner rubber, say, an inch away?
>>
>>
>
>Yep... the junctions on either (longitudinal) side of the tube always seem to get stretched out...
>
>
>
May help to use a larger diameter tube. Not a guarantee against failure at the valve but should
help. The rubber at the valve doesn't stretch as much as the rest of the tube and so there's stress
there. Use the largest diameter tube that'll work with your tire. By not having to stretch so much
it will also hold air longer between refils and offer a bit more protection from punctures. I
recently helped someone with a flat and just couldn't believe the size of their tube. It was like
one of those little skinny birthday balloons. When did track-bike stuff become the ideal?

--------------000802040403080800060806 Content-Type: text/html; charset=us-ascii
Content-Transfer-Encoding: 7bit

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title></title>
</head> <body> <br> <br> Phil wrote:<br> <blockquote type="cite"
cite="[email protected]"> <blockquote type="cite"> <pre wrap="">How
the heck did you get the patch wrapped around the valve? </pre> </blockquote> <pre wrap=""><!----> I
cut the patch a couple mm at the end that wrapped around the valve.

</pre> <blockquote type="cite"> <pre wrap="">Was it the junction between thicker rubber near the
valve, and thinner rubber, say, an inch away? </pre> </blockquote> <pre wrap=""><!----> Yep... the
junctions on either (longitudinal) side of the tube always seem to get stretched out...

</pre> </blockquote> May help to use a larger diameter tube. Not a guarantee against failure
at the valve but should help. The rubber at the valve doesn't stretch as much as the rest of
the tube and so there's stress there. Use the largest diameter tube that'll work with your
tire. By not having to stretch so much it will also hold air longer between refils and offer
a bit more protection from punctures. I recently helped someone with a flat and just
couldn't believe the size of their tube. It was like one of those little skinny birthday
balloons. When did track-bike stuff become the ideal?<br> </body> </html>

--------------000802040403080800060806--
 
J

John Albergo

Guest
A Muzi wrote:

>
>
>
>In commercial practice we don't (didn't) scrape. We used Tech brand patch cleaner ( contains
>trichlor and xylene, IIRC)
>
>
You (and the ozone layer) are probably better off that you stopped the practice. Then again when we
were kids we though the essential part of patching was to light the glue on fire. Toxins galore.
 
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