Scuffing a tube before patching necessary?



T

Tom Nakashima

Guest
My reason for asking,
I recently got a flat and used the one spare tube I carry, but got another
the same day. I realized I had a flat kit, but forgot to back the sandpaper
when I patched a tube at home. I just used water to clean the area
before gluing and patching with a 16mm round Rema patch. It seems to
be holding out ok. All this time I've been scuffing a tube, now wondering
what's the use?
-tom
 
Tom Nakashima wrote:
> My reason for asking,
> I recently got a flat and used the one spare tube I carry, but got another
> the same day. I realized I had a flat kit, but forgot to back the sandpaper
> when I patched a tube at home. I just used water to clean the area
> before gluing and patching with a 16mm round Rema patch. It seems to
> be holding out ok. All this time I've been scuffing a tube, now wondering
> what's the use?
> -tom
>
>



Scuffing the tube is to get rid of the release stuff from the mold.
There are other ways to remove it. At home I always use white spirit and
never use sandpaper. I have a 100% score with that. On the road you can
scuff the tube on the pavement to get rid of the mold release.

Lou
--
Posted by news://news.nb.nu (http://www.nb.nu)
 
On Thu, 3 May 2007 13:52:28 -0700, "Tom Nakashima"
<[email protected]> wrote:

>My reason for asking,
>I recently got a flat and used the one spare tube I carry, but got another
>the same day. I realized I had a flat kit, but forgot to back the sandpaper
>when I patched a tube at home. I just used water to clean the area
>before gluing and patching with a 16mm round Rema patch. It seems to
>be holding out ok. All this time I've been scuffing a tube, now wondering
>what's the use?
>-tom


I think that you need to scuff the tube in order to remove the mold
release compound that is on the surface. I'd imagine if you use your
glue first to solvent remove the layer and then put it on for patching
it might work.

I was using Methy Ethyl Ketone to remove the mold release and found it
easier to just have some coarse, cloth backed, sandpaper. One piece
of the paper and you've got scuffing papers for life.
 
Tom Nakashima wrote:
>
> My reason for asking,
> I recently got a flat and used the one spare tube I carry, but got another
> the same day. I realized I had a flat kit, but forgot to back the sandpaper
> when I patched a tube at home. I just used water to clean the area
> before gluing and patching with a 16mm round Rema patch. It seems to
> be holding out ok. All this time I've been scuffing a tube, now wondering
> what's the use?


In addition to breaking through the layer of mold release and
increasing the surface area of the glue bond, rigorous sanding of the
patch area can also remove the seam ridges on the tube, which might
otherwise create channels through which air pressure can seep. I
always sand until the ridges and their adjoining mold release are
gone, if the patch will intersect a seam.

Other than sandpaper, I have used metal files, sharp knife blades, or
even a cement curb to rough up the affected area.

It's easy and cheap to do an experiment by bonding patches to sanded
and unsanded sections of an old tube, and testing them to see how
easily they lift and peel. If I were doing such an experiment, I'd
leave them inflated to full pressure in a tire overnight to compress
and cure them thoroughly.

Chalo
 
Tom Nakashima wrote:
> My reason for asking,
> I recently got a flat and used the one spare tube I carry, but got another
> the same day. I realized I had a flat kit, but forgot to back the sandpaper
> when I patched a tube at home. I just used water to clean the area
> before gluing and patching with a 16mm round Rema patch. It seems to
> be holding out ok. All this time I've been scuffing a tube, now wondering
> what's the use?


The intent of the sandpaper or 'cheese grater' is to clean the surface
of the tube, much as one scuffs off a layer of skin when kissing the
pavement. Some riders prefer to carry a tube along and patch later in a
more relaxed environment, using a volatile solvent instead of a scraper.
A successful patch begins with removal of the wax/mold release/
oxides/crud on the tube's surface so the cement is able to melt the
patch into the tube. At any rate don't touch the scuffed or solvent
cleaned area after cleaning. Oil from your fingers doesn't help.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
 
Tom Nakashima writes:

> My reason for asking, I recently got a flat and used the one spare
> tube I carry, but got another the same day. I realized I had a flat
> kit, but forgot to back the sandpaper when I patched a tube at home.
> I just used water to clean the area before gluing and patching with
> a 16mm round Rema patch. It seems to be holding out OK. All this
> time I've been scuffing a tube, now wondering what's the use?


You must have seen this before but here is a link:

http://www.sheldonbrown.com/brandt/patching.html
http://www.sheldonbrown.com/brandt/tube-failure.html

Jobst Brandt
 
On Thu, 3 May 2007 13:52:28 -0700, Tom Nakashima wrote:

Yes. If you don't do it the patch is likely to fail before long.
I've had 100% success with patches since I started (a)
doing this properly (b) waiting for the solvent to dry properly.

But if you plan to toss the tube when you get home, it
probably doesn't matter.

--
Home page: http://members.westnet.com.au/mvw
 
On Thu, 03 May 2007 19:03:25 -0500, A Muzi wrote:

> The intent of the sandpaper or 'cheese grater' is to clean the surface
> of the tube, much as one scuffs off a layer of skin when kissing the
> pavement. Some riders prefer to carry a tube along and patch later in a
> more relaxed environment, using a volatile solvent instead of a scraper.


I don't know /anyone/ who carries a patch kit but no tube. Quite a few
people have a large bag and carry two.

--
Home page: http://members.westnet.com.au/mvw
 
Michael Warner wrote:
> On Thu, 03 May 2007 19:03:25 -0500, A Muzi wrote:
>
>> The intent of the sandpaper or 'cheese grater' is to clean the surface
>> of the tube, much as one scuffs off a layer of skin when kissing the
>> pavement. Some riders prefer to carry a tube along and patch later in a
>> more relaxed environment, using a volatile solvent instead of a scraper.

>
> I don't know /anyone/ who carries a patch kit but no tube. Quite a few
> people have a large bag and carry two.
>

you do now - for road riding at least.
 
On Thu, 3 May 2007 13:52:28 -0700, "Tom Nakashima"
<[email protected]> may have said:

>My reason for asking,
>I recently got a flat and used the one spare tube I carry, but got another
>the same day. I realized I had a flat kit, but forgot to back the sandpaper
>when I patched a tube at home. I just used water to clean the area
>before gluing and patching with a 16mm round Rema patch. It seems to
>be holding out ok. All this time I've been scuffing a tube, now wondering
>what's the use?


*Sometimes* other cleaning methods work, but not always. *Sometimes*
an unscuffed but solvent-claned surface produces a good bond, but
(once again) not always.

If you've got a puncture, a patch, and a way to clean the surface,
you've got a good chance of success. If you've got a tube of cement
with more than just a couple of drops left in it, and no other way to
clean the tube, I've have passable results by just dabbing on some
glue, letting it soak for a few seconds, and then scraping it off with
a pocketknife, or in one instance, scraping it off on the sharp-ish
edge of the rim.

In order of level of success from highest to lowest, I've found that
vigorous scuffing with a good abarasive cloth works best, followed by
sandpaper, followed by a near-tie between degreasing cleaners and
oil-free solvents, followed by cleaning using patch cement, followed
by just wiping the bejeesus out of it with the bottom end of my
T-shirt...which is barely better than no cleaning at all.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.
 
On 2007-05-04, Michael Warner <[email protected]> wrote:
> On Thu, 03 May 2007 19:03:25 -0500, A Muzi wrote:
>
>> The intent of the sandpaper or 'cheese grater' is to clean the surface
>> of the tube, much as one scuffs off a layer of skin when kissing the
>> pavement. Some riders prefer to carry a tube along and patch later in a
>> more relaxed environment, using a volatile solvent instead of a scraper.

>
> I don't know /anyone/ who carries a patch kit but no tube. Quite a few
> people have a large bag and carry two.


I just carry a patch kit and no tube, although I don't particularly
recommend this.
 
On Fri, 04 May 2007 04:42:31 -0500, Ben C <[email protected]> wrote:


>I just carry a patch kit and no tube, although I don't particularly
>recommend this.


I just carry a spare tubular.

(detour!)

:)
 
On Fri, 04 May 2007 04:42:31 -0500, Ben C <[email protected]> wrote:

>On 2007-05-04, Michael Warner <[email protected]> wrote:
>> On Thu, 03 May 2007 19:03:25 -0500, A Muzi wrote:
>>
>>> The intent of the sandpaper or 'cheese grater' is to clean the surface
>>> of the tube, much as one scuffs off a layer of skin when kissing the
>>> pavement. Some riders prefer to carry a tube along and patch later in a
>>> more relaxed environment, using a volatile solvent instead of a scraper.

>>
>> I don't know /anyone/ who carries a patch kit but no tube. Quite a few
>> people have a large bag and carry two.

>
>I just carry a patch kit and no tube, although I don't particularly
>recommend this.


Dear Ben,

I once saw a gaudily dressed fellow on an expensive-looking bike stop
on the highway ahead of me as I was climbing the ridge west of Pueblo.

By the time I arrived, he'd yanked out a section of tube without
removing his wheel, slapped a glueless patch on the goathead puncture,
and was re-inflating his tire with a whiff from a CO2 cartridge.

After a few words about goatheads, he zoomed off over the top of the
ridge toward Wetmore (little more than a T-intersection with some
farms and summer cabins), apparently confident that he had enough
patches and CO2 for a 60-mile round trip through nowhere.

Cheers,

Carl Fogel
 
The title of this thread is unfortunate as much as chains stretching
from climbing steep hills. Patching a tube has nothing to do with
surface roughness (scuffing). The purpose of sanding the area to be
patched is to remove the "skin" or surface that was in contact with
the mold during manufacture. This surface contains mold release,
sprayed into the mold to allow the it to be separated from the mold.
Cheese graters cannot do that reasonably and convey the wrong message
about th operation.

Also mentioned in this thread were mold ridges left on the tube from
mold segment boundaries. These can leave leak channels if they are
close to the perforation. The ridges cannot be sand papered away but
are easily removed by a throw-away plastic razor that fits in a patch
kit if its handle is cut off. A BIC single blade is best for this
because it does not clog as easily as others with successive closely
spaced blades that clog even when shaving a beard.

Jobst Brandt
 
[email protected] wrote:
> The title of this thread is unfortunate as much as chains stretching
> from climbing steep hills. Patching a tube has nothing to do with
> surface roughness (scuffing). The purpose of sanding the area to be
> patched is to remove the "skin" or surface that was in contact with
> the mold during manufacture. This surface contains mold release,
> sprayed into the mold to allow the it to be separated from the mold.
> Cheese graters cannot do that reasonably and convey the wrong message
> about th operation.
>
> Also mentioned in this thread were mold ridges left on the tube from
> mold segment boundaries. These can leave leak channels if they are
> close to the perforation. The ridges cannot be sand papered away


That's news to me. I just did so last weekend on a heavily ridged tube.

Greg
--
The ticketbastard Tax Tracker:
http://www.ticketmastersucks.org/tracker.html

Dethink to survive - Mclusky
 
On 04 May 2007 19:02:14 GMT, [email protected] wrote:

> A BIC single blade is best for this
>because it does not clog as easily as others with successive closely
>spaced blades that clog even when shaving a beard.


Is it possible to buy single edge BIC's anymore?
 
On Thu, 03 May 2007 19:54:29 -0700, jim beam wrote:

>> I don't know /anyone/ who carries a patch kit but no tube. Quite a few
>> people have a large bag and carry two.
>>

> you do now - for road riding at least.


What do you do when your tube isn't patchable e.g. it tears away at the
stem or suffers a blowout or cut too large to be patched?

If you have two tubes, the odds that neither can be patched are extremely
small.

--
Home page: http://members.westnet.com.au/mvw
 
Michael Warner wrote:
> On Thu, 03 May 2007 19:54:29 -0700, jim beam wrote:
>
>>> I don't know /anyone/ who carries a patch kit but no tube. Quite a few
>>> people have a large bag and carry two.
>>>

>> you do now - for road riding at least.

>
> What do you do when your tube isn't patchable e.g. it tears away at the
> stem or suffers a blowout or cut too large to be patched?
>
> If you have two tubes, the odds that neither can be patched are extremely
> small.
>

frankly, i've never had an irreparable problem on a road tube. i've had
mountain tubes utterly shredded when tires have blown off or punctured
and subsequently snake-bitten, but never that with road. my biggest
concern for road is a tire slash where the gap in the casing is too
large and the tube pokes through. can't ride that. i'll carry a spare
tire before i carry a spare tube on the road, and indeed, for commuting
where i don't have all day to putz about, i always /do/ carry a spare tire.
 
On Fri, 04 May 2007 19:58:16 -0700, jim beam
<[email protected]> wrote:

>Michael Warner wrote:
>> On Thu, 03 May 2007 19:54:29 -0700, jim beam wrote:
>>
>>>> I don't know /anyone/ who carries a patch kit but no tube. Quite a few
>>>> people have a large bag and carry two.
>>>>
>>> you do now - for road riding at least.

>>
>> What do you do when your tube isn't patchable e.g. it tears away at the
>> stem or suffers a blowout or cut too large to be patched?
>>
>> If you have two tubes, the odds that neither can be patched are extremely
>> small.
>>

>frankly, i've never had an irreparable problem on a road tube. i've had
>mountain tubes utterly shredded when tires have blown off or punctured
>and subsequently snake-bitten, but never that with road. my biggest
>concern for road is a tire slash where the gap in the casing is too
>large and the tube pokes through. can't ride that. i'll carry a spare
>tire before i carry a spare tube on the road, and indeed, for commuting
>where i don't have all day to putz about, i always /do/ carry a spare tire.


Dear Jim,

I carry a spare folding tire rolled up in a seat bag and spare tubes
in a frame bag.

Riding my rear brake slowly downhill while waiting for a friend turned
out to be a bad idea. When I felt an odd thumping, I stopped, saw the
bead creeping off the rim, and was frantically reaching for the Presta
valve to let the air out when--

Bang!

Splat!

http://i18.tinypic.com/4t9hswg.jpg

Here's the unrepairable Slime tube with its rip propped open with a
spoke and the Kevlar bead torn out of the tan sidewall propped open
with a fold of the tube:

http://i19.tinypic.com/53r4dp0.jpg

With the spare tire, tube, and pump, it was an easy roadside repair,
but it amused the hell out of my friend. Glad I didn't have to walk
five miles home in the summer sun.

Cheers,

Carl Fogel
 
On 2007-05-05, Michael Warner <[email protected]> wrote:
> On Thu, 03 May 2007 19:54:29 -0700, jim beam wrote:
>
>>> I don't know /anyone/ who carries a patch kit but no tube. Quite a few
>>> people have a large bag and carry two.
>>>

>> you do now - for road riding at least.

>
> What do you do when your tube isn't patchable e.g. it tears away at the
> stem or suffers a blowout or cut too large to be patched?


I had one tear away a bit at the stem once. It was a cause for mild
panic, but I bodged it up with a patch and it got me home. It is
sensible to carry a spare tube.