Tricks for TIG welding Tri-clamp short-weld ferrules?

[pinkmaster]

I'm hoping someone might share some tricks for welding sanitary 304 SS Tri-clamp-style short-weld ferrules to tubing without warping the ferrule. I've tried tightly clamping the ferrule to another or a cap to hold it, but the clamp gets in the way and it will still warp if it gets hot enough. I've tried making additional tack welds for the fit-up, but that doesn't seem to impact the flanged edge of the ferrule itself. Years ago, an experienced sanitary welder told me short weld ferrules were tough, but I don't remember what he said about how to avoid the problems. My guess is it all comes down to getting the weld accomplished with as little heat as possible. Until my technique improves or I can get access to a machine with more rapid pulsing, I'm not sure what else to do.

[shovelon]

I feel for ya.

Are you purging?

[pinkmaster]

I feel for ya.

Are you purging?

Oh, yeah... it would be really ugly without the purge. I've mostly been trying to make my own short branch tees, which gets pretty tricky trying to get in the tight space between the run off the tee and the clamped/capped ferrule. One idea I had was to create something of a heat-sink in the form of a solid cylinder with a slightly flanged "ferrule" on the end that I could clamp onto? I don't know...

[shovelon]

I have made expanding mandrels for repair work on alum bike frames.

MTBR frame forum members have made them out of brass. I think Paragon machine Works (cycle products) markets something similar.http://www.paragonmachineworks.com/storename/paragonmachineworks/ViewDept-261334.aspx

Perhaps a copper cylinder with tapered threaded fittings to expand, and the flange would indeed do the trick.

[pinkmaster]

I have made expanding mandrels for repair work on alum bike frames.

MTBR frame forum members have made them out of brass. I think Paragon machine Works (cycle products) markets something similar.http://www.paragonmachineworks.com/storename/paragonmachineworks/ViewDept-261334.aspx

Perhaps a copper cylinder with tapered threaded fittings to expand, and the flange would indeed do the trick.

So, do you think the idea of holding the ferrule straight is the answer or doing a better job of dissipating the heat? I'm not sure I entirely understand what these devices do.

[shovelon]

The upper one holds it straight and is a blocking shoe for alum, the copper one holds straight and acts like a heat sink for steel.