Frame rust: Worst case scenario
Kirk Van Deraa
I have the oportunity to buy an mid '80's Bianchi for not much, but there
are several places on the outside of the frame where the paint is gone and
rust has formed. I can repaint the frame, but my question is: Is there
anyone who has actual experience with frames failing (i.e. coming apart)
due to internal corrosion? I often see writers in the magazines say
"...but after a while I was afraid to ride my (fill in the blank of some
steel bike here)
on fast descents.." as justification to buy the newest Titanium (or carbon
or AL) wonder bike.
I know that good steel tubing is quite thin, so a little rust can go a long way.
I plan on shining a flashlight down the seat tube to check for visible
rust there.
So, exactly how *dangerous* is a steel frame that has rust?
Kirk
Benson H. Tongue
In article <montage-1612...@d107.nwchi.interaccess.com>,
Kirk Van Deraa <mon...@montage.com> wrote:
>I have the oportunity to buy an mid '80's Bianchi for not much, but there
>are several places on the outside of the frame where the paint is gone and
>rust has formed. I can repaint the frame, but my question is: Is there
>anyone who has actual experience with frames failing (i.e. coming apart)
>
>Kirk
your second question to some degree. How dangerous is a steel frame
that has rust? Not very. (usually). Iron oxide particles are quite
large in comparison with the original amount of metal that combined
with the oxygen to form the oxide. Thus you'll get a thick coating of
oxide when only a very small amount of steel has been "eaten." Unless
the bike has been sitting exposed to the elements for a long time (with
exposed metal) it's unlikely that the frame is going to be noticeably
weakened. If you're really concerned, I'd remove the surface rust and see
how deep rust has eaten into the steel. If the surface still looks
flush then there's no particular problem.
Benson
Prof. Benson H. Tongue
Mechanical Engineering
University of California at Berkeley
bhto...@euler.me.berkeley.edu
Garry Lee
This is not a scientific opinion BUT a bike shop owner of 20 years told me
that he had never seen 531 or equivalent get a serious rust problem. (i.e.
deep rust). This is in Ireland, Rust City Arizona.
Mike Dearing
I wouldnt worry too much - Im riding on 1920s lightweights that are quite
rusty.... I have a Sunbeam Royal lightweight that has some serious pitting
on the crossbar and down tube and it still performs beautifully....
alot of relatively recent frames have rust under the paint - due to the
practise of the tubing being rubbed down with emery or similar before
priming (alot of Italian frames have this done) all good frames are NOT
done this way - they are blasted before primer: it keys better and
ensures a corrosion free start in life - also the chances of the frame
rusting thru from the inside is very unlikely unless the frame is
chromed, and the tubes are 'boxed' in without through holes - then
sometimes the pickling
chemicals remain and burn their way thru the tubes eventually - but this
again takes a lot of time (some late 40s and early 50s all chrome hetchins
can be seen with this condition....)
Mike :7)
Bob Lovellette
Garry Lee <gl...@iol.ie> wrote in article <595jg4$6is$1...@nuacht.iol.ie>...
Would you like to lift my 1974 Vollis with 531 main tubes and listen to the
rust roll around inside the tubes. Or do you consider a rust problem
"serious" when the rust completely penetrates the tubes.
Bob Lovellette
Santa Monica, California -- One mile from the Ocean
b...@annex.com
Garry Lee
>
>Would you like to lift my 1974 Vollis with 531 main tubes and listen to the
>rust roll around inside the tubes. Or do you consider a rust problem
>"serious" when the rust completely penetrates the tubes.
Living near the sea is a special case. I am no expert on bike rust but a
frame of that age which is near the sea all the time owes you nothing.
Throw it out.
Melissa & Jim
>> This is not a scientific opinion BUT a bike shop owner of 20 years told
>me
>> that he had never seen 531 or equivalent get a serious rust problem.
>(i.e.
>> deep rust). This is in Ireland, Rust City Arizona.
I HAVE seen a 531 frame rusted all the way through from the inside
out. On the one I saw it was the top tube that was perforated. The
pinholes were just about where one would expect the thin end of the
taper to be about 4" behind the headset. Before the rust bubbled
through, the paint had been intact.
Jim
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Melissa Kepner Jim Adney
mgke...@facstaff.wisc.edu jim....@mpcug.com
Laura Kepner-Adney
Madison, Wisconsin
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Andy Dingley
The moving finger of Garry Lee <gl...@iol.ie> having written:
>This is not a scientific opinion BUT a bike shop owner of 20 years told me
>that he had never seen 531 or equivalent get a serious rust problem.
I've just retired my 50 year old frame because I ran out of
funny-sized aluminium parts with the right obscure threads. Barring a
few sets of stems and bars, I don't think I've a single aluminium
component left that has the structural integrity of a Crunchie bar.
Storage has been somewhat careless over the years, a few miles inland
from the sea in a rainy part of the country,
The steel frame, however, is as solid as ever.
--
Do whales have krillfiles ?