Welding a titanium frame

"Friday" wrote: (clip) I know plenty of good welders but I'm not sure if
they could do titanium. Is there anything I have to watch out for?
^^^^^^^^^^^^^^
There certainly is. Titanium has to be welded with a shielded arc (TIG).
The problem is that the inside of the tubing has to be shielded as well. I
would consult a frame builder who has titanium experience, and see whether
there is a practical technique for reworking a completed frame.

Friday said:

I have a titanium mountain bike frame that I love but would like to put
disk brakes on it. Is it difficult to weld a bracket onto the rear of a
titanium frame? I know plenty of good welders but I'm not sure if they
could do titanium. Is there anything I have to watch out for?

yes, the thickness of the stay tubes. thin tubes bend under disk
braking loads. you need to add a web between the seat stay and the
wheel stay to mitigate the issue - and it needs to be done right.

In article <[email hidden]>, Friday

() said:

I have a titanium mountain bike frame that I love but would like to put
disk brakes on it. Is it difficult to weld a bracket onto the rear of a
titanium frame? I know plenty of good welders but I'm not sure if they
could do titanium. Is there anything I have to watch out for?

Have you considered using something like this:

<URL:http://www.gearshift.co.uk/acatalog/info_K720q.html>

A lot less hassle than welding...

--
Dave Larrington - <http://www.legslarry.beerdrinkers.co.uk/>
Although the hippopotamus hath no sting in its tail, the wise man would
rather be seated upon the back of a bee.

In article <[email hidden]>, [email hidden] says...

Quoted message said:

I have a titanium mountain bike frame that I love but would like to put
disk brakes on it. Is it difficult to weld a bracket onto the rear of a
titanium frame? I know plenty of good welders but I'm not sure if they
could do titanium. Is there anything I have to watch out for?

It takes special equipment to weld titanium. Unless the welders you know are
experienced and have the proper equipment, they will not do a good job. They
will probably end up ruining your frame.
---------------
Alex

Friday said:

I have a titanium mountain bike frame that I love but would like to put
disk brakes on it. Is it difficult to weld a bracket onto the rear of a
titanium frame? I know plenty of good welders but I'm not sure if they
could do titanium. Is there anything I have to watch out for?

These guys want $300 to do it:

http://www.ticycles.com/store/repair.html#frame

One is left to wonder if this kind of investment into an older frame
makes sense.

-nate

Llatikcuf said:

Friday said:

I have a titanium mountain bike frame that I love but would like to put
disk brakes on it. Is it difficult to weld a bracket onto the rear of a
titanium frame? I know plenty of good welders but I'm not sure if they
could do titanium. Is there anything I have to watch out for?

These guys want $300 to do it:

http://www.ticycles.com/store/repair.html#frame

One is left to wonder if this kind of investment into an older frame
makes sense.

My thoughts exactly. The other posts on this subject covered most of
the issues (though it's not necessary to plumb the inside of the stay
with gas unless you're going to open it up to install the brake
mounts).

Something else to think about - consider mounting plain ol' canti
brakes on the back of the bike. You'll get disc-like modulation, save
a bundle of cash and a bunch of weight and complexity, and you'll
still have lots more braking power than you can reasonably use.

Unless it's primarily a fashion thing, of course... ;-)

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

"Mark Hickey" wrote: (clip) The other posts on this subject covered most
of the issues (though it's not necessary to plumb the inside of the stay
with gas unless you're going to open it up to install the brake mounts).
(clip)
^^^^^^^^^^^^^^^^^
How are you going to keep the inside of the tube from oxidizing? Frame
tubing is fairly thin, and the inside is going to get almost as hot as the
outside from the weld.

In article <[email hidden]>, [email hidden]
says...

Quoted message said:

Something else to think about - consider mounting plain ol' canti
brakes on the back of the bike. You'll get disc-like modulation, save
a bundle of cash and a bunch of weight and complexity, and you'll
still have lots more braking power than you can reasonably use.

Not to mention that good canti's can be had dirt cheap.

The drawback is that all that cash he saved will weigh him down. 🙂
---------------
Alex

Mark Hickey said:

Llatikcuf said:

Friday said:

I have a titanium mountain bike frame that I love but would like to put
disk brakes on it. Is it difficult to weld a bracket onto the rear of a
titanium frame? I know plenty of good welders but I'm not sure if they
could do titanium. Is there anything I have to watch out for?

These guys want $300 to do it:

http://www.ticycles.com/store/repair.html#frame

One is left to wonder if this kind of investment into an older frame
makes sense.

My thoughts exactly. The other posts on this subject covered most of
the issues (though it's not necessary to plumb the inside of the stay
with gas unless you're going to open it up to install the brake
mounts).

Something else to think about - consider mounting plain ol' canti
brakes on the back of the bike. You'll get disc-like modulation, save
a bundle of cash and a bunch of weight and complexity, and you'll
still have lots more braking power than you can reasonably use.

Unless it's primarily a fashion thing, of course... ;-)

Reality, what a concept...way too many people get discs cuz of the
meeting at the coffee shop before they drive to ride somewhere.....

Quoted message said:

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

Leo Lichtman said:

^^^^^^^^^^^^^^^^^
How are you going to keep the inside of the tube from oxidizing? Frame
tubing is fairly thin, and the inside is going to get almost as hot as the
outside from the weld.

It's not hot, it's contamination of the bead.
Phil Brown

Leo Lichtman said:

"Mark Hickey" wrote: (clip) The other posts on this subject covered most
of the issues (though it's not necessary to plumb the inside of the stay
with gas unless you're going to open it up to install the brake mounts).
(clip)
^^^^^^^^^^^^^^^^^
How are you going to keep the inside of the tube from oxidizing? Frame
tubing is fairly thin, and the inside is going to get almost as hot as the
outside from the weld.

The oxidation should be limited to the surface on the inside of the
seat stay tube, which won't affect the strength of the weld.

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

philcycles said:

Leo Lichtman said:

^^^^^^^^^^^^^^^^^
How are you going to keep the inside of the tube from oxidizing? Frame
tubing is fairly thin, and the inside is going to get almost as hot as the
outside from the weld.

It's not hot, it's contamination of the bead.
Phil Brown

Contamination with oxygen, yes. Which is available inside air-filled
tubes. I don't know if there is sufficient oxygen in a tube to be a
problem--any chemists reading this?

--
Ted Bennett

In article
<[email hidden]>
,

Ted Bennett said:

philcycles said:

Leo Lichtman said:

^^^^^^^^^^^^^^^^^
How are you going to keep the inside of the tube from oxidizing? Frame
tubing is fairly thin, and the inside is going to get almost as hot as the
outside from the weld.

It's not hot, it's contamination of the bead.
Phil Brown

Contamination with oxygen, yes. Which is available inside air-filled
tubes. I don't know if there is sufficient oxygen in a tube to be a
problem--any chemists reading this?

Just as much as on the outside.

--
Michael Press

Michael Press said:

Ted Bennett said:

philcycles said:

Leo Lichtman wrote:

> ^^^^^^^^^^^^^^^^^
> How are you going to keep the inside of the tube from oxidizing? Frame
> tubing is fairly thin, and the inside is going to get almost as hot as
> the
> outside from the weld.

It's not hot, it's contamination of the bead.
Phil Brown

Contamination with oxygen, yes. Which is available inside air-filled
tubes. I don't know if there is sufficient oxygen in a tube to be a
problem--any chemists reading this?

Just as much as on the outside.

I don't think so. There is a limited volume inside the tube in
question. It's sealed at both ends.

--
Ted Bennett

In article
<[email hidden]>
,

Ted Bennett said:

Michael Press said:

Ted Bennett said:

"philcycles" <[email hidden]> wrote:

> Leo Lichtman wrote:
>
> > ^^^^^^^^^^^^^^^^^
> > How are you going to keep the inside of the tube from oxidizing? Frame
> > tubing is fairly thin, and the inside is going to get almost as hot as
> > the
> > outside from the weld.
>
> It's not hot, it's contamination of the bead.
> Phil Brown

Contamination with oxygen, yes. Which is available inside air-filled
tubes. I don't know if there is sufficient oxygen in a tube to be a
problem--any chemists reading this?

Just as much as on the outside.

I don't think so. There is a limited volume inside the tube in
question. It's sealed at both ends.

Fork blades typically have weep holes. No guarantee.

--
Michael Press