Hi,
Is there some compound or liquid that I can spray or rub on between
parts that will keep them from fusing from the heat of nearby welding?

I'm welding three pieces of tubing to a structure, and they have to
line up precisely, so I've got to have a shaft holding them in place.
The problem is that the heat causes the shaft to get stuck. I don't
think that I'm welding through the side (I'm quicker than that) but
something is fusing it in place. Any help for this?

Thanks, --Max

Max Krippler wrote:
Hi,
Is there some compound or liquid that I can spray or rub on between
parts that will keep them from fusing from the heat of nearby welding?

I'm welding three pieces of tubing to a structure, and they have to
line up precisely, so I've got to have a shaft holding them in place.
The problem is that the heat causes the shaft to get stuck. I don't
think that I'm welding through the side (I'm quicker than that) but
something is fusing it in place. Any help for this?

Are you sure the parts aren't just moving from the weld and binding on the
shaft? As opposed to actually fusing? Is your shaft reaching a welding heat?

The solution sounds simple in concept - use a different clamping scheme.

WE

On Sun, 11 Dec 2005 18:27:02 GMT, Max Krippler
wrote:

Hi,
Is there some compound or liquid that I can spray or rub on between
parts that will keep them from fusing from the heat of nearby welding?

I'm welding three pieces of tubing to a structure, and they have to
line up precisely, so I've got to have a shaft holding them in place.
The problem is that the heat causes the shaft to get stuck. I don't
think that I'm welding through the side (I'm quicker than that) but
something is fusing it in place. Any help for this?


It probably won't stop the sticking but a high temp anti-seize would
at least keep it from galling together when you go to take it out.

If done properly the weld won't be sticking to the shaft. However
every time you weld the tube you shrink it and pull it out of
alignment with the others. There's not really anything that can be
done about this since it's the nature of welding to shrink stuff.

The key to this job is the put the shaft in there. Lightly tack all
of the pieces in place (preferable in about 4 places 2 top and 2
bottom). Then remove the shaft and do the welding.

Afterwards if the pieces that go in the tubes are a good fit before
welding you'll likely have to ream the holes in order for them to fit
again. This is why you need some clearance on a job like this
preferably .010" or more.

Wayne Cook
Shamrock, TX
http://members.dslextreme.com/users/waynecook/index.htm

My guess is that the welding distorts the tubing, which causes the shaft
to get stuck. Even if the opening stays round, the welded metal shrinks
when it gets cold, so that could use up all the clearance. If you had a
smaller diameter shaft with more "Play" you might be able to avoid the
problem. Even 0.010 inch more clearance might be enough to enable you
to remove the shaft after welding. I would probably try for 0.020 inch
clearance before welding, but I am not sure that is enough.

If you cannot live with that much clearance you might want to use the
shaft to get the initial alignment, then clamp the tubing externally and
remove the shaft after welding.

Yet another approach would be to make an alignment bushing or whatever
that you would plan to leave in place after the weld, so it would not
matter if you could not extract it. If absolute accuracy was needed,
this could be the way to go. Perhaps the bushing could be internally
threaded, so you could position the bushing with a threaded rod (Only
engaged a couple of turns) and then unscrew the threaded rod.

Whatever, you will need to experiment until you figure out what will
work, before you start trying to build the final product.

Richard


Max Krippler wrote:
Hi,
Is there some compound or liquid that I can spray or rub on between
parts that will keep them from fusing from the heat of nearby welding?

I'm welding three pieces of tubing to a structure, and they have to
line up precisely, so I've got to have a shaft holding them in place.
The problem is that the heat causes the shaft to get stuck. I don't
think that I'm welding through the side (I'm quicker than that) but
something is fusing it in place. Any help for this?

Thanks, --Max


--
http://www.fergusonsculpture.com
Sculptures in copper and other metals

Max, I can't add anything to the other posters, they are all excellent
answers. I've been there/ done that. How about letting us know how you
finally solve your problem. Hey, maybe you can teach US something with
a new approach to an old problem. Bill.

I'll almost gurantee that you are distorting BOTH the bushings them
selves as well as the alignment between the bushings. If your 'bushings'
are really thin tube, double that.

You might want to experiment with just one tube, use your rod through
the center, weld on one side, pull the rod out, measure the resulting
inner diameter. Expect to find the tube egg shaped in the .030" range,
and bent by .020"to .050" over a couple of inches.

If things are critical, you will have to consider boring, reaming or
drilling after welding.

Max Krippler wrote:
Hi,
Is there some compound or liquid that I can spray or rub on between
parts that will keep them from fusing from the heat of nearby welding?

I'm welding three pieces of tubing to a structure, and they have to
line up precisely, so I've got to have a shaft holding them in place.
The problem is that the heat causes the shaft to get stuck. I don't
think that I'm welding through the side (I'm quicker than that) but
something is fusing it in place. Any help for this?

Thanks, --Max

In article ,
Max Krippler wrote:

Hi,
Is there some compound or liquid that I can spray or rub on between
parts that will keep them from fusing from the heat of nearby welding?

I'm welding three pieces of tubing to a structure, and they have to
line up precisely, so I've got to have a shaft holding them in place.
The problem is that the heat causes the shaft to get stuck. I don't
think that I'm welding through the side (I'm quicker than that) but
something is fusing it in place. Any help for this?

Thanks, --Max

Well it might not help, but I use Nozzle dip on bolts when I need to
weld nuts to something.

--
"I love deadlines, especially the wooshing sound they make as
they fly by" - Douglas Adams

Max Krippler wrote:

Is there some compound or liquid that I can spray or rub on between
parts that will keep them from fusing from the heat of nearby welding?

First, I would use anti-splatter-spray (you use that for MIG/MAG/TIG).
But second, I would check how the current flows. I guess it's going
through that shaft.
Of course, I always have a copper hammer that solves many problems like
these without leaving a trace. :-)


Nick
--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de
DIY-DRO - YADRO - Eigenbau-Digitalanzeige

Max Krippler wrote:

Hi,
Is there some compound or liquid that I can spray or rub on between
parts that will keep them from fusing from the heat of nearby welding?

I'm welding three pieces of tubing to a structure, and they have to
line up precisely, so I've got to have a shaft holding them in place.
The problem is that the heat causes the shaft to get stuck. I don't
think that I'm welding through the side (I'm quicker than that) but
something is fusing it in place. Any help for this?

Thanks, --Max

If the shrinkage is causing the stuckage, could you cut a couple wide slots
in the shaft? That would make it more like a spring, letting you drive it
out. Maybe use a pipe instead of a shaft? Easier to cut the slots that way.


--
--Marc

On 11 Dec 2005 11:56:01 -0800, with neither quill nor qualm,
quickly quoth:

Max, I can't add anything to the other posters, they are all excellent
answers. I've been there/ done that. How about letting us know how you
finally solve your problem. Hey, maybe you can teach US something with
a new approach to an old problem. Bill.

I'll ditto Bill here but add that if you're arc/tig/mig welding, you
need to watch how you ground the parts. Grounding to the loose tube
might arc it to the other parts. If OA welding, perhaps a couple of
thin, non-metallic shims between the parts would do the trick in case
of welding deformations. I've seen thin phenolic sheet which might
work when used as narrow shimstock. It would provide clearance even if
you had to break it out after the welding.


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