Tube Soake In Oil Results

Last month, I took a piece of inner tube that had been
soaking in oil (forgotten for a few months) and found that
Joe Riel was quite right about oil reducing the tensile
strength of butyl rubber--I found that I could pull the
piece of inner tube apart into oddly rectangular chunks,
smaller and smaller, without much effort, while an unoiled
piece from the same inner tube just stretched, even when cut
into thinner and thinner strips:

http://groups-beta.google.com/group/...bb7cae81741162

This picture shows the oiled piece turned into confetti with
my bare fingers (I'm no Schwarzenegger) with the unoiled
piece (cut into three thinner and thinner strips with
scissors) that I couldn't tear apart:

http://home.comcast.net/~carlfogel/d...d/tube_oil.jpg

Those are two ordinary paper staples holding the widest
unoiled strip down, which gives some idea of size. The three
long strips rolled together form a section of 700c inner
tube running from top to bottom of the picture.

Intrigued, I stuffed a whole inner tube into a plastic jar,
filled it with 10w-40, and forgot about it until a post just
now from Mark Hickey reminded me that he had wondered about
oil from a chain getting onto the tube by running down the
valve stem.

I took the tube out to the trash can in the alley, wiped it
off, and inflated it with a hand pump until it was about 4
feet tall.

Nothing happened, so I got a dry inner tube of the same
brand from the garage, and inflated it to the same size.

Obviously, the oil hadn't weakened the tube enough to
matter, so I carried it back into the garage, still
inflated, to wipe it off some more and publish my incredible
negative results.

Bang!

The oiled tube exploded while I was carrying it, a 2 & 1/4"
split about a foot from the valve along a seam running the
long way around the inside curve.

Intrigued again, I deflated and compared the two tubes. The
oiled tube had stretched to about 18 inches longer than the
similarly inflated dry tube.

It's not easy to measure such low pressures, but neither
tube would raise the needle on my floor pump--a stroke of
the pump would see about 5 psi, the tube would expand, and
the needle would drop to 0.

The constraint of the tire and rim would limit the tube
expansion, but the tube would bulge and stretch a bit into
the valve hole and around the heads of spoke nipples and so
forth.

Again, I take back what I said long ago about oil not
affecting inner tubes. Here's Joe's post predicting that
butyl inner tubes (with "poor oil resistance") will lose
"more than 60%" of their tensile strength when contaminated:

http://groups-beta.google.com/group/...f2e67d73d5045d

Joe's post is a little bit up from where that link takes
you.

Carl Fogel

Carl Fogel writes:

Last month, I took a piece of inner tube that had been
soaking in oil (forgotten for a few months) and found that
Joe Riel was quite right about oil reducing the tensile
strength of butyl rubber--I found that I could pull the
piece of inner tube apart into oddly rectangular chunks,
smaller and smaller, without much effort, while an unoiled
piece from the same inner tube just stretched, even when cut
into thinner and thinner strips:

I took the tube out to the trash can in the alley, wiped it
off, and inflated it with a hand pump until it was about 4
feet tall.

Nothing happened, so I got a dry inner tube of the same
brand from the garage, and inflated it to the same size.

From your description, it seems we need a different test, one of
installing a tube that has been similarly treated and then ride it
until something fails. From what you say, the oiled tube had enough
elasticity to stretch substantially. In the tire, reasonably sized
tubes do not do that.

Your test showed that there is deterioration but not that it made the
tube unserviceable. Besides, it sounded like an extreme case of
casual oil getting on the tube. This seldom occurs to this degree.
That is why I don't think this can be used to explain mysterious tube
failures often reported here. Proffering this concept here only leads
to more excuses for failed tubes that in fact failed for faulty
installation or maintenance.

wrote:
Carl Fogel writes:


Last month, I took a piece of inner tube that had been
soaking in oil (forgotten for a few months) and found that
Joe Riel was quite right about oil reducing the tensile
strength of butyl rubber--I found that I could pull the
piece of inner tube apart into oddly rectangular chunks,
smaller and smaller, without much effort, while an unoiled
piece from the same inner tube just stretched, even when cut
into thinner and thinner strips:


I took the tube out to the trash can in the alley, wiped it
off, and inflated it with a hand pump until it was about 4
feet tall.


Nothing happened, so I got a dry inner tube of the same
brand from the garage, and inflated it to the same size.


From your description, it seems we need a different test, one of
installing a tube that has been similarly treated and then ride it
until something fails. From what you say, the oiled tube had enough
elasticity to stretch substantially. In the tire, reasonably sized
tubes do not do that.

Your test showed that there is deterioration but not that it made the
tube unserviceable.

"ladies & gentlemen, this is your captain speaking. some of you may
have noticed the loud explosion that blew #4 engine off the wing and
ruptured the fuel tanks, but please don't be alarmed. we assure you
that the other 3 engines work perfectly."

Besides, it sounded like an extreme case of
casual oil getting on the tube. This seldom occurs to this degree.
That is why I don't think this can be used to explain mysterious tube
failures often reported here. Proffering this concept here only leads
to more excuses for failed tubes that in fact failed for faulty
installation or maintenance.

Jim,

If you've got a point then please state it.

I already got the message, over many threads, that jobst b. seems
to rub you up the wrong way: You can take that as a given,
no need to keep hammering it home.

wrote:
Jim,

If you've got a point then please state it.

I already got the message, over many threads, that jobst b. seems
to rub you up the wrong way: You can take that as a given,
no need to keep hammering it home.

the point is, if anyone bothered to check, is that butyl rubbers /are/
degraded by mineral oils. but jobst didn't bother checking facts before
he announced that there was no harm caused, so he's now casting about
with weasily excuses which amount to bad advice. bottom line, if you do
oil spoke nipples, you run the risk of having that oil seep through to
the tube and the tube can rupture. that can spoil your day,
particularly on a long fast downhill with bends in it and oncoming
traffic. sure, tires puncture due to road hazards as well, but why
multiply the risk?

What isn't clear to me is what a small amount of lubricating oil, suc
as what could seep through a spoke nipple or perhaps a valve stem hole
does to a butyl tube over a longer time span than Mr. Fogel's tests. I
is clear to me that large amounts of oil will degrade butyl rubber, an
fairly quickly in terms of expected inner tube lifespan.

At this point all I can say is that I will be cautious about gettin
lube on my innertubes

--
waxbytes

jim beam wrote:
wrote:

Jim,

If you've got a point then please state it.

I already got the message, over many threads, that jobst b. seems
to rub you up the wrong way: You can take that as a given,
no need to keep hammering it home.

the point is, if anyone bothered to check, is that butyl rubbers /are/
degraded by mineral oils. but jobst didn't bother checking facts before
he announced that there was no harm caused, so he's now casting about
with weasily excuses which amount to bad advice. bottom line, if you do
oil spoke nipples, you run the risk of having that oil seep through to
the tube and the tube can rupture. that can spoil your day,
particularly on a long fast downhill with bends in it and oncoming
traffic. sure, tires puncture due to road hazards as well, but why
multiply the risk?


Yes, you should never risk oil-contaminated tubes when hauling
nitroglycerin past orphanages.

On Mon, 27 Jun 2005 03:07:03 +1000, waxbytes
wrote:


What isn't clear to me is what a small amount of lubricating oil, such
as what could seep through a spoke nipple or perhaps a valve stem hole,
does to a butyl tube over a longer time span than Mr. Fogel's tests. It
is clear to me that large amounts of oil will degrade butyl rubber, and
fairly quickly in terms of expected inner tube lifespan.

At this point all I can say is that I will be cautious about getting
lube on my innertubes.

Dear Waxbytes,

It's not clear to me, either.

On the one hand, the tubes that I mistreated suffered for
only a month or two, not the year or two that seems more
likely for normal tubes.

On the other hand, the tubes held their breath under far
more oil than any normal tube would ever see.

On the third hand, the original tube section that I ended up
pulling to pieces was oiled on both the inside and outside
surface, since it was just a short section of tube cut with
scissors. The intact tube that blew out was presumably dry
inside, just like an inner tube in real use.

(But the rubber on the supposedly dry tube seems to be just
as oily as the outside--I suspect that the oil soaks into
the tube, which remains shiny and feels different than a
normal tube no matter how much it's washed and wiped off.)

On the fourth hand, there's the question of pressure.

The tubes that I euthanized endured no more oil pressure
than the depth of the oil, which wasn't much--an inch in the
case of the small section, and about 5 inches in the case of
the tube folded up and stuffed into an oil-filled plastic
jar.

Oil on an already-inflated real tube would have no pressure
if it dripped down the valve stem, but the oil would be at
around 100 psi if it got onto the tube from the spokes and
rim tape before inflation.

The children who raft down the nearby Arkansas River on
large inner tubes would be wise to reject tubes with oil
stains. I like to think that my bicycling standards are at
least as high.

Carl Fogel

On Sun, 26 Jun 2005 13:56:27 -0600,
wrote:

[snip]

(But the rubber on the supposedly dry tube seems to be just
as oily as the outside--I suspect that the oil soaks into
the tube, which remains shiny and feels different than a
normal tube no matter how much it's washed and wiped off.)

[snip]

A client open on Sunday had an electronic postal scale that
read only in ounces, but that was more than good enough.

The dry tube weighed 3.8 ounces.

The same model tube from the same batch that sat in oil for
a month or so weighed 7.0 ounces.

After I cut both tubes and measured, the oil tube turned out
to have expanded permanently to 21 inches longer than the
dry tube, just from being blown up outside a tire.

Carl Fogel

jim beam writes:

bottom line, if you do oil spoke nipples, you run the risk of having
that oil seep through to the tube and the tube can rupture.

Why would someone oil spoke nipples rather than grease spoke nipples
?? It seems to me that you don't want the lubrication to be gone in a
few days or after a few rides, so that you can retrue a wheel a few
weeks or months later, and that grease ( which is oil plus soap ) is
the only way to achieve this happy state.

I think that with a suitable rim strip - such as velox - grease would
have a hard time getting to the inner tube area.

- Don Gillies
San Diego, CA