Perforated seat tube on Steel bontrager, options?



M

Martin O'Loughlin

Guest
Whilst cleaning my Bontrager Race earlier made the unhappy discovery
that it has two small holes in the seat tube, two-three millimeters in
diameter just below the level of the bottom of the seat post.

It would seem the frame has rusted from the inside out. I like this
frame and don't want to scrap it. So what are the options i face?

The frame is Tig welded, and i know in theory brazed frames can have
tubes replaced, but this is an option i would rather not take if
possible, expensive if nothing else.

Using a torch i discovered a fair amount of mud and **** and found its
way into the frame. The easton Seatpost had an open top so easy route
in... Taken the frame in the shower and hopefully cleaned all this out,
currently letting the frame dry out. But it does seem a little rough
inside, which hints at more corrosion. I know that if i can keep the
air, steel and water apart then a steel frame will never corrode is
there any product that might prevent any further corrosion? I have been
using the frame in its current state for a while so i don't forsee any
catastrophic failure happening over night.

Would a frame builder be able to give any hints as too the extent of
the problem, i had thought of respraying it in the summer anyway. so
would a sandblast stripdown be extreme enough to highlight any serious
problems. With any minor holes being filled?

Thanks

MO
 
On 2006-12-17, Martin O'Loughlin <[email protected]> wrote:
> Whilst cleaning my Bontrager Race earlier made the unhappy discovery
> that it has two small holes in the seat tube, two-three millimeters in
> diameter just below the level of the bottom of the seat post.
>
> It would seem the frame has rusted from the inside out. I like this
> frame and don't want to scrap it. So what are the options i face?
>
> The frame is Tig welded, and i know in theory brazed frames can have
> tubes replaced, but this is an option i would rather not take if
> possible, expensive if nothing else.
>
> Using a torch i discovered a fair amount of mud and **** and found its
> way into the frame. The easton Seatpost had an open top so easy route
> in... Taken the frame in the shower and hopefully cleaned all this out,
> currently letting the frame dry out. But it does seem a little rough
> inside, which hints at more corrosion. I know that if i can keep the
> air, steel and water apart then a steel frame will never corrode is
> there any product that might prevent any further corrosion?

You could try Waxoyl I suppose. We used to spray this highly-regarded
substance wherever we could on our British cars, including inside box
sections. I found this link:

http://www.waxoyl.com/en/produkte/120-4.htm

I'm sure I've read that bike frames do get water in them and there are
supposed to be drain holes in the BB shell, perhaps those are blocked.
 
On Dec 17, 3:12 pm, Martin O'Loughlin <[email protected]> wrote:
> Whilst cleaning my Bontrager Race earlier made the unhappy discovery
> that it has two small holes in the seat tube, two-three millimeters in
> diameter just below the level of the bottom of the seat post.
>
> It would seem the frame has rusted from the inside out. I like this
> frame and don't want to scrap it. So what are the options i face?
>
> The frame is Tig welded, and i know in theory brazed frames can have
> tubes replaced, but this is an option i would rather not take if
> possible, expensive if nothing else.
>
> Using a torch i discovered a fair amount of mud and **** and found its
> way into the frame. The easton Seatpost had an open top so easy route
> in... Taken the frame in the shower and hopefully cleaned all this out,
> currently letting the frame dry out. But it does seem a little rough
> inside, which hints at more corrosion. I know that if i can keep the
> air, steel and water apart then a steel frame will never corrode is
> there any product that might prevent any further corrosion? I have been
> using the frame in its current state for a while so i don't forsee any
> catastrophic failure happening over night.
>
> Would a frame builder be able to give any hints as too the extent of
> the problem, i had thought of respraying it in the summer anyway. so
> would a sandblast stripdown be extreme enough to highlight any serious
> problems. With any minor holes being filled?
>
> Thanks
>
> MO

Dear MO,

A framebuilder can indeed repair this frame. How much do you like it?
(as in how much $).

Several ways to do it: cut the whole seat tube out below the cluster
and TIG in a new one, ream afterward; external steel sleeve over the
rusted area and braze or TIG; internal sleeve (look for an old Avenir
chrome-moly seat post in the right size) and braze or silver solder.

I would go with the external sleeve, maybe make it out of 28.6mm x .9
mm tubing, split and make some decorative cutouts that would also allow
you to check that the bronze or silver got in through and through.
This is a job I would do under $*** YMMV.

good luck

jn

"Thursday"
 
Martin O'Loughlin wrote:
> Whilst cleaning my Bontrager Race earlier made the unhappy discovery
> that it has two small holes in the seat tube, two-three millimeters in
> diameter just below the level of the bottom of the seat post.
>
> It would seem the frame has rusted from the inside out. I like this
> frame and don't want to scrap it. So what are the options i face?
>
> The frame is Tig welded, and i know in theory brazed frames can have
> tubes replaced, but this is an option i would rather not take if
> possible, expensive if nothing else.
>
> Using a torch i discovered a fair amount of mud and **** and found its
> way into the frame. The easton Seatpost had an open top so easy route
> in... Taken the frame in the shower and hopefully cleaned all this out,
> currently letting the frame dry out. But it does seem a little rough
> inside, which hints at more corrosion. I know that if i can keep the
> air, steel and water apart then a steel frame will never corrode is
> there any product that might prevent any further corrosion? I have been
> using the frame in its current state for a while so i don't forsee any
> catastrophic failure happening over night.
>
> Would a frame builder be able to give any hints as too the extent of the
> problem, i had thought of respraying it in the summer anyway. so would a
> sandblast stripdown be extreme enough to highlight any serious problems.
> With any minor holes being filled?
>
> Thanks
>
> MO
>
>
why would tube rust at the /top/, away from any moisture run? i think
you're just looking at the vent holes - they're drilled during
manufacture to ensure weld integrity. just leave them. or throw the
frame away and ride aluminum instead.
 
Martin O'Loughlin wrote:
> Whilst cleaning my Bontrager Race earlier made the unhappy discovery
> that it has two small holes in the seat tube, two-three millimeters in
> diameter just below the level of the bottom of the seat post.
>
> It would seem the frame has rusted from the inside out. I like this
> frame and don't want to scrap it. So what are the options i face?

> Using a torch i discovered a fair amount of mud and **** and found its
> way into the frame. ...

This sounds even better to an American ear (where "torch" means
blowtorch instead of flashlight).

But anyway, the "right" way to do this is to replace the tube or sleeve
it. The not-so-right way would be to clean the tube out pretty
thoroughly, put some rust-deterrent stuff on it, and replace the
seatpost with a long one that sticks down below where the holes
are (a sort of makeshift internal sleeve). It's not a high stress
area of the frame (compared to the downtube, say). Inspect
regularly to make sure the holes don't get bigger. I had a Bridgestone
MTB whose seat tube got a small narrow vertical cut during a
cutting-the-old-seatpost-out adventure, and it never seemed to
get any worse after I did this.
 
Martin O'Loughlin wrote:
> Whilst cleaning my Bontrager Race earlier made the unhappy discovery
> that it has two small holes in the seat tube, two-three millimeters in
> diameter just below the level of the bottom of the seat post.
>
> It would seem the frame has rusted from the inside out. I like this
> frame and don't want to scrap it. So what are the options i face?

Have the tube replaced by a frame builder but chances are, this isn't
the only place you have a rust problem...
>
> The frame is Tig welded, and i know in theory brazed frames can have
> tubes replaced, but this is an option i would rather not take if
> possible, expensive if nothing else.
>
> Using a torch i discovered a fair amount of mud and **** and found its
> way into the frame. The easton Seatpost had an open top so easy route
> in... Taken the frame in the shower and hopefully cleaned all this out,
> currently letting the frame dry out. But it does seem a little rough
> inside, which hints at more corrosion. I know that if i can keep the
> air, steel and water apart then a steel frame will never corrode is
> there any product that might prevent any further corrosion? I have been
> using the frame in its current state for a while so i don't forsee any
> catastrophic failure happening over night.
>
> Would a frame builder be able to give any hints as too the extent of
> the problem, i had thought of respraying it in the summer anyway. so
> would a sandblast stripdown be extreme enough to highlight any serious
> problems. With any minor holes being filled?
>
> Thanks
>
> MO
 
jim beam wrote:
> Martin O'Loughlin wrote:
>
>> Whilst cleaning my Bontrager Race earlier made the unhappy discovery
>> that it has two small holes in the seat tube, two-three millimeters in
>> diameter just below the level of the bottom of the seat post.
>>
>> It would seem the frame has rusted from the inside out. I like this
>> frame and don't want to scrap it. So what are the options i face?
>>
>> The frame is Tig welded, and i know in theory brazed frames can have
>> tubes replaced, but this is an option i would rather not take if
>> possible, expensive if nothing else.
>>
>> Using a torch i discovered a fair amount of mud and **** and found its
>> way into the frame. The easton Seatpost had an open top so easy route
>> in... Taken the frame in the shower and hopefully cleaned all this
>> out, currently letting the frame dry out. But it does seem a little
>> rough inside, which hints at more corrosion. I know that if i can keep
>> the air, steel and water apart then a steel frame will never corrode
>> is there any product that might prevent any further corrosion? I have
>> been using the frame in its current state for a while so i don't
>> forsee any catastrophic failure happening over night.
>>
>> Would a frame builder be able to give any hints as too the extent of
>> the problem, i had thought of respraying it in the summer anyway. so
>> would a sandblast stripdown be extreme enough to highlight any serious
>> problems. With any minor holes being filled?
>>
>> Thanks
>>
>> MO
>>
>>
> why would tube rust at the /top/, away from any moisture run? i think
> you're just looking at the vent holes - they're drilled during
> manufacture to ensure weld integrity. just leave them. or throw the
> frame away and ride aluminum instead.

I agree that rust at the /top/ is curious, but I have /never/ seen vent
holes in a /seat/ tube. Seat stays, yes. Chain stays, fork blades, yes
- they would otherwise be airtight when brazing/welding is finished.

But why would you need a vent hole in a seat tube? Wouldn't it vent
just fine at both ends? Were you serious, or did you misread the
original post?

Mark J.
 
Mark wrote:
> jim beam wrote:
>> Martin O'Loughlin wrote:
>>
>>> Whilst cleaning my Bontrager Race earlier made the unhappy discovery
>>> that it has two small holes in the seat tube, two-three millimeters
>>> in diameter just below the level of the bottom of the seat post.
>>>
>>> It would seem the frame has rusted from the inside out. I like this
>>> frame and don't want to scrap it. So what are the options i face?
>>>
>>> The frame is Tig welded, and i know in theory brazed frames can have
>>> tubes replaced, but this is an option i would rather not take if
>>> possible, expensive if nothing else.
>>>
>>> Using a torch i discovered a fair amount of mud and **** and found
>>> its way into the frame. The easton Seatpost had an open top so easy
>>> route in... Taken the frame in the shower and hopefully cleaned all
>>> this out, currently letting the frame dry out. But it does seem a
>>> little rough inside, which hints at more corrosion. I know that if i
>>> can keep the air, steel and water apart then a steel frame will never
>>> corrode is there any product that might prevent any further
>>> corrosion? I have been using the frame in its current state for a
>>> while so i don't forsee any catastrophic failure happening over night.
>>>
>>> Would a frame builder be able to give any hints as too the extent of
>>> the problem, i had thought of respraying it in the summer anyway. so
>>> would a sandblast stripdown be extreme enough to highlight any
>>> serious problems. With any minor holes being filled?
>>>
>>> Thanks
>>>
>>> MO
>>>
>>>
>> why would tube rust at the /top/, away from any moisture run? i think
>> you're just looking at the vent holes - they're drilled during
>> manufacture to ensure weld integrity. just leave them. or throw the
>> frame away and ride aluminum instead.
>
> I agree that rust at the /top/ is curious, but I have /never/ seen vent
> holes in a /seat/ tube. Seat stays, yes. Chain stays, fork blades, yes
> - they would otherwise be airtight when brazing/welding is finished.
>
> But why would you need a vent hole in a seat tube? Wouldn't it vent
> just fine at both ends? Were you serious, or did you misread the
> original post?
>
> Mark J.
>
misread - well spotted!

re-reading, it sounds like the seat post has worn through the seat tube,
maybe as a result of corrosion abrasion. time to replace the frame i'd say.
 
On Mon, 18 Dec 2006 20:47:23 -0800, jim beam wrote:

> Mark wrote:
>> jim beam wrote:
>>> Martin O'Loughlin wrote:
>>>
>>>> Whilst cleaning my Bontrager Race earlier made the unhappy discovery
>>>> that it has two small holes in the seat tube, two-three millimeters
>>>> in diameter just below the level of the bottom of the seat post.
>>>>
>>>> It would seem the frame has rusted from the inside out. I like this
>>>> frame and don't want to scrap it. So what are the options i face?
>>>>
>>>> The frame is Tig welded, and i know in theory brazed frames can have
>>>> tubes replaced, but this is an option i would rather not take if
>>>> possible, expensive if nothing else.
>>>>
>>>> Using a torch i discovered a fair amount of mud and **** and found
>>>> its way into the frame. The easton Seatpost had an open top so easy
>>>> route in... Taken the frame in the shower and hopefully cleaned all
>>>> this out, currently letting the frame dry out. But it does seem a
>>>> little rough inside, which hints at more corrosion. I know that if i
>>>> can keep the air, steel and water apart then a steel frame will never
>>>> corrode is there any product that might prevent any further
>>>> corrosion? I have been using the frame in its current state for a
>>>> while so i don't forsee any catastrophic failure happening over night.
>>>>
>>>> Would a frame builder be able to give any hints as too the extent of
>>>> the problem, i had thought of respraying it in the summer anyway. so
>>>> would a sandblast stripdown be extreme enough to highlight any
>>>> serious problems. With any minor holes being filled?
>>>>
>>>> Thanks
>>>>
>>>> MO
>>>>
>>>>
>>> why would tube rust at the /top/, away from any moisture run? i think
>>> you're just looking at the vent holes - they're drilled during
>>> manufacture to ensure weld integrity. just leave them. or throw the
>>> frame away and ride aluminum instead.
>>
>> I agree that rust at the /top/ is curious, but I have /never/ seen vent
>> holes in a /seat/ tube. Seat stays, yes. Chain stays, fork blades, yes
>> - they would otherwise be airtight when brazing/welding is finished.
>>
>> But why would you need a vent hole in a seat tube? Wouldn't it vent
>> just fine at both ends? Were you serious, or did you misread the
>> original post?
>>
>> Mark J.
>>
> misread - well spotted!
>
> re-reading, it sounds like the seat post has worn through the seat tube,
> maybe as a result of corrosion abrasion. time to replace the frame i'd say.

Are you saying that this was caused by friction between the seat post and
seat tube? (Presumably exacerbated by corrosion -- but of the seat post or
the seat tube?)

If so, why would the abrasions be below the end of the seatpost?

My thought was that perhaps some of the "mud and ****" that the OP found
was lodged at the end of the seatpost, at least temporarily. That might
leave moisture pressed against the seat tube at that point. I don't have
any direct experience of that, but I have heard similar accounts here on
rbt -- e.g., someone discovering rust where he had inserted a
paper business card into a seat tube.
 
Gary Young wrote:
> On Mon, 18 Dec 2006 20:47:23 -0800, jim beam wrote:
>
>> Mark wrote:
>>> jim beam wrote:
>>>> Martin O'Loughlin wrote:
>>>>
>>>>> Whilst cleaning my Bontrager Race earlier made the unhappy discovery
>>>>> that it has two small holes in the seat tube, two-three millimeters
>>>>> in diameter just below the level of the bottom of the seat post.
>>>>>
>>>>> It would seem the frame has rusted from the inside out. I like this
>>>>> frame and don't want to scrap it. So what are the options i face?
>>>>>
>>>>> The frame is Tig welded, and i know in theory brazed frames can have
>>>>> tubes replaced, but this is an option i would rather not take if
>>>>> possible, expensive if nothing else.
>>>>>
>>>>> Using a torch i discovered a fair amount of mud and **** and found
>>>>> its way into the frame. The easton Seatpost had an open top so easy
>>>>> route in... Taken the frame in the shower and hopefully cleaned all
>>>>> this out, currently letting the frame dry out. But it does seem a
>>>>> little rough inside, which hints at more corrosion. I know that if i
>>>>> can keep the air, steel and water apart then a steel frame will never
>>>>> corrode is there any product that might prevent any further
>>>>> corrosion? I have been using the frame in its current state for a
>>>>> while so i don't forsee any catastrophic failure happening over night.
>>>>>
>>>>> Would a frame builder be able to give any hints as too the extent of
>>>>> the problem, i had thought of respraying it in the summer anyway. so
>>>>> would a sandblast stripdown be extreme enough to highlight any
>>>>> serious problems. With any minor holes being filled?
>>>>>
>>>>> Thanks
>>>>>
>>>>> MO
>>>>>
>>>>>
>>>> why would tube rust at the /top/, away from any moisture run? i think
>>>> you're just looking at the vent holes - they're drilled during
>>>> manufacture to ensure weld integrity. just leave them. or throw the
>>>> frame away and ride aluminum instead.
>>> I agree that rust at the /top/ is curious, but I have /never/ seen vent
>>> holes in a /seat/ tube. Seat stays, yes. Chain stays, fork blades, yes
>>> - they would otherwise be airtight when brazing/welding is finished.
>>>
>>> But why would you need a vent hole in a seat tube? Wouldn't it vent
>>> just fine at both ends? Were you serious, or did you misread the
>>> original post?
>>>
>>> Mark J.
>>>
>> misread - well spotted!
>>
>> re-reading, it sounds like the seat post has worn through the seat tube,
>> maybe as a result of corrosion abrasion. time to replace the frame i'd say.
>
> Are you saying that this was caused by friction between the seat post and
> seat tube? (Presumably exacerbated by corrosion -- but of the seat post or
> the seat tube?)

yes.

>
> If so, why would the abrasions be below the end of the seatpost?

/at/ the end of the seatpost. there's white powder at the bottom of my
carbon post where this kind of wear is occurring. other than
interference fit, there's no way of stopping it, but it sure will be
worse if wear /and/ corrosion are present.

>
> My thought was that perhaps some of the "mud and ****" that the OP found
> was lodged at the end of the seatpost, at least temporarily. That might
> leave moisture pressed against the seat tube at that point. I don't have
> any direct experience of that, but I have heard similar accounts here on
> rbt -- e.g., someone discovering rust where he had inserted a
> paper business card into a seat tube.
 
On Tue, 19 Dec 2006 07:43:50 -0800, jim beam wrote:

> Gary Young wrote:
>> On Mon, 18 Dec 2006 20:47:23 -0800, jim beam wrote:
>>
>>> Mark wrote:
>>>> jim beam wrote:
>>>>> Martin O'Loughlin wrote:
>>>>>
>>>>>> Whilst cleaning my Bontrager Race earlier made the unhappy discovery
>>>>>> that it has two small holes in the seat tube, two-three millimeters
>>>>>> in diameter just below the level of the bottom of the seat post.
>>>>>>
>>>>>> It would seem the frame has rusted from the inside out. I like this
>>>>>> frame and don't want to scrap it. So what are the options i face?
>>>>>>
>>>>>> The frame is Tig welded, and i know in theory brazed frames can have
>>>>>> tubes replaced, but this is an option i would rather not take if
>>>>>> possible, expensive if nothing else.
>>>>>>
>>>>>> Using a torch i discovered a fair amount of mud and **** and found
>>>>>> its way into the frame. The easton Seatpost had an open top so easy
>>>>>> route in... Taken the frame in the shower and hopefully cleaned all
>>>>>> this out, currently letting the frame dry out. But it does seem a
>>>>>> little rough inside, which hints at more corrosion. I know that if i
>>>>>> can keep the air, steel and water apart then a steel frame will never
>>>>>> corrode is there any product that might prevent any further
>>>>>> corrosion? I have been using the frame in its current state for a
>>>>>> while so i don't forsee any catastrophic failure happening over night.
>>>>>>
>>>>>> Would a frame builder be able to give any hints as too the extent of
>>>>>> the problem, i had thought of respraying it in the summer anyway. so
>>>>>> would a sandblast stripdown be extreme enough to highlight any
>>>>>> serious problems. With any minor holes being filled?
>>>>>>
>>>>>> Thanks
>>>>>>
>>>>>> MO
>>>>>>
>>>>>>
>>>>> why would tube rust at the /top/, away from any moisture run? i think
>>>>> you're just looking at the vent holes - they're drilled during
>>>>> manufacture to ensure weld integrity. just leave them. or throw the
>>>>> frame away and ride aluminum instead.
>>>> I agree that rust at the /top/ is curious, but I have /never/ seen vent
>>>> holes in a /seat/ tube. Seat stays, yes. Chain stays, fork blades, yes
>>>> - they would otherwise be airtight when brazing/welding is finished.
>>>>
>>>> But why would you need a vent hole in a seat tube? Wouldn't it vent
>>>> just fine at both ends? Were you serious, or did you misread the
>>>> original post?
>>>>
>>>> Mark J.
>>>>
>>> misread - well spotted!
>>>
>>> re-reading, it sounds like the seat post has worn through the seat tube,
>>> maybe as a result of corrosion abrasion. time to replace the frame i'd say.
>>
>> Are you saying that this was caused by friction between the seat post and
>> seat tube? (Presumably exacerbated by corrosion -- but of the seat post or
>> the seat tube?)
>
> yes.
>
>>
>> If so, why would the abrasions be below the end of the seatpost?
>
> /at/ the end of the seatpost. there's white powder at the bottom of my
> carbon post where this kind of wear is occurring. other than
> interference fit, there's no way of stopping it, but it sure will be
> worse if wear /and/ corrosion are present.
>

It seems odd to me that an aluminum seatpost would abrade a steel frame
tube. Wouldn't you expect to see rather severe damage to the seatpost?
Maybe the OP can tell us about the condition of the seatpost.
>>
>> My thought was that perhaps some of the "mud and ****" that the OP
>> found was lodged at the end of the seatpost, at least temporarily. That
>> might leave moisture pressed against the seat tube at that point. I
>> don't have any direct experience of that, but I have heard similar
>> accounts here on rbt -- e.g., someone discovering rust where he had
>> inserted a paper business card into a seat tube.
 
Martin O'Loughlin wrote:
> Whilst cleaning my Bontrager Race earlier made the unhappy discovery
> that it has two small holes in the seat tube, two-three millimeters in
> diameter just below the level of the bottom of the seat post.
>
> It would seem the frame has rusted from the inside out. I like this
> frame and don't want to scrap it. So what are the options i face?
>
> The frame is Tig welded, and i know in theory brazed frames can have
> tubes replaced, but this is an option i would rather not take if
> possible, expensive if nothing else.
>
> Using a torch i discovered a fair amount of mud and **** and found its
> way into the frame. The easton Seatpost had an open top so easy route
> in... Taken the frame in the shower and hopefully cleaned all this
> out, currently letting the frame dry out. But it does seem a little
> rough inside, which hints at more corrosion. I know that if i can
> keep the air, steel and water apart then a steel frame will never
> corrode is there any product that might prevent any further
> corrosion? I have been using the frame in its current state for a
> while so i don't forsee any catastrophic failure happening over night.
>
> Would a frame builder be able to give any hints as too the extent of
> the problem, i had thought of respraying it in the summer anyway. so
> would a sandblast stripdown be extreme enough to highlight any serious
> problems. With any minor holes being filled?
>
> Thanks
>
> MO


Can you provide us with pictures?

--
Phil
 
On 2006-12-19 15:57:55 +0000, Gary Young <[email protected]> said:

> On Tue, 19 Dec 2006 07:43:50 -0800, jim beam wrote:
>
>> Gary Young wrote:
>>> On Mon, 18 Dec 2006 20:47:23 -0800, jim beam wrote:
>>>
>>>> Mark wrote:
>>>>> jim beam wrote:
>>>>>> Martin O'Loughlin wrote:
>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>> why would tube rust at the /top/, away from any moisture run? i think
>>>>>> you're just looking at the vent holes - they're drilled during
>>>>>> manufacture to ensure weld integrity. just leave them. or throw the
>>>>>> frame away and ride aluminum instead.
>>>>> I agree that rust at the /top/ is curious, but I have /never/ seen vent
>>>>>
Not vent holes, wrong place, wrong shape.

the holes are c40mm below the end of a carbon seatpin???????????
certainly not abrasion, the post doesn't move.

no idea????????

my only guess is that some of the **** lodged at the level of the holes
and facilitated corrosion.

i have sanded the frame, cleaned off the corrosion as best i can and
applied some hammerite. not having any waxoyl have poured chain lube
down seat tube in hope it will lessen any corrosion until i can get
something more appropriate.

..
 
Gary Young wrote:
> On Tue, 19 Dec 2006 07:43:50 -0800, jim beam wrote:
>
>> Gary Young wrote:
>>> On Mon, 18 Dec 2006 20:47:23 -0800, jim beam wrote:
>>>
>>>> Mark wrote:
>>>>> jim beam wrote:
>>>>>> Martin O'Loughlin wrote:
>>>>>>
>>>>>>> Whilst cleaning my Bontrager Race earlier made the unhappy discovery
>>>>>>> that it has two small holes in the seat tube, two-three millimeters
>>>>>>> in diameter just below the level of the bottom of the seat post.
>>>>>>>
>>>>>>> It would seem the frame has rusted from the inside out. I like this
>>>>>>> frame and don't want to scrap it. So what are the options i face?
>>>>>>>
>>>>>>> The frame is Tig welded, and i know in theory brazed frames can have
>>>>>>> tubes replaced, but this is an option i would rather not take if
>>>>>>> possible, expensive if nothing else.
>>>>>>>
>>>>>>> Using a torch i discovered a fair amount of mud and **** and found
>>>>>>> its way into the frame. The easton Seatpost had an open top so easy
>>>>>>> route in... Taken the frame in the shower and hopefully cleaned all
>>>>>>> this out, currently letting the frame dry out. But it does seem a
>>>>>>> little rough inside, which hints at more corrosion. I know that if i
>>>>>>> can keep the air, steel and water apart then a steel frame will never
>>>>>>> corrode is there any product that might prevent any further
>>>>>>> corrosion? I have been using the frame in its current state for a
>>>>>>> while so i don't forsee any catastrophic failure happening over night.
>>>>>>>
>>>>>>> Would a frame builder be able to give any hints as too the extent of
>>>>>>> the problem, i had thought of respraying it in the summer anyway. so
>>>>>>> would a sandblast stripdown be extreme enough to highlight any
>>>>>>> serious problems. With any minor holes being filled?
>>>>>>>
>>>>>>> Thanks
>>>>>>>
>>>>>>> MO
>>>>>>>
>>>>>>>
>>>>>> why would tube rust at the /top/, away from any moisture run? i think
>>>>>> you're just looking at the vent holes - they're drilled during
>>>>>> manufacture to ensure weld integrity. just leave them. or throw the
>>>>>> frame away and ride aluminum instead.
>>>>> I agree that rust at the /top/ is curious, but I have /never/ seen vent
>>>>> holes in a /seat/ tube. Seat stays, yes. Chain stays, fork blades, yes
>>>>> - they would otherwise be airtight when brazing/welding is finished.
>>>>>
>>>>> But why would you need a vent hole in a seat tube? Wouldn't it vent
>>>>> just fine at both ends? Were you serious, or did you misread the
>>>>> original post?
>>>>>
>>>>> Mark J.
>>>>>
>>>> misread - well spotted!
>>>>
>>>> re-reading, it sounds like the seat post has worn through the seat tube,
>>>> maybe as a result of corrosion abrasion. time to replace the frame i'd say.
>>> Are you saying that this was caused by friction between the seat post and
>>> seat tube? (Presumably exacerbated by corrosion -- but of the seat post or
>>> the seat tube?)
>> yes.
>>
>>> If so, why would the abrasions be below the end of the seatpost?
>> /at/ the end of the seatpost. there's white powder at the bottom of my
>> carbon post where this kind of wear is occurring. other than
>> interference fit, there's no way of stopping it, but it sure will be
>> worse if wear /and/ corrosion are present.
>>
>
> It seems odd to me that an aluminum seatpost would abrade a steel frame
> tube. Wouldn't you expect to see rather severe damage to the seatpost?

not necessarily. synergy between wear and corrosion can give dramatic
results, especially where there are dissimilar metals.

> Maybe the OP can tell us about the condition of the seatpost.
>>> My thought was that perhaps some of the "mud and ****" that the OP
>>> found was lodged at the end of the seatpost, at least temporarily. That
>>> might leave moisture pressed against the seat tube at that point. I
>>> don't have any direct experience of that, but I have heard similar
>>> accounts here on rbt -- e.g., someone discovering rust where he had
>>> inserted a paper business card into a seat tube.
 
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