[DavesTent]

Hello folks,

I’m getting ready to TIG weld my next project. It is made of 1” x 4” x 0.120 rectangular 6061. The corners are mitred. It is a horizontal rectangular frame with the long sides 10’, the short sides 6’. It will be a tight fit in my shop, and I won’t have enough bench space to fixture/clamp it wholly, so may have to do it a couple of pieces at a time.
I’m just wondering the best order of operations for welding it up and trying to keep it square?
I’m thinking:
Top & Bottom (wrapping the beads slightly over the corners) inside to outside
Outside corner
Inside fillet (2F?)

I’ve been practicing on the mitre offcuts, but it’s hard to tell warpage with such short sections (~3-4”)

Any/all advice/criticism is welcomed!

[Simclardy]

You could weld a jig to hold the corner square. Basicly, a copy of your big piece but just one corner and clamp it.


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[TraditionalToolworks]

Weld your miters from the inside out to keep it as square as possible. At least that's what I do, I saw it in one of Jody's videos.

[cj737]

Tack the living dog piss out of it. Keeping it from racking will be a bigger challenge than keeping it square. In all cases, clamping helps.

Aluminum shrinks heavily during welding. So it may remain square, but will "taco" on you unless you are patient, keep things clamped fully until cool, and use a decent sequence to control the distortion.

Something to bear in mind: When you weld up a tube frame, you trap all the gas and pressure within it. When you attempt to weld the final joint, you will struggle with the expanding gases unless you make/leave a vent hole. Simply drill a 1/8" hole midway down a tube length. Weld your corners. Then when things cool down, spot weld the hole shut and grind it flush.

[DavesTent]

Thanks folks! I’m going to try and clear out the shop and build a jig on the floor that I can clamp it to. The “taco effect” is actually my bigger concern too. I think taking my time and just doing really small sections with plenty of time between for cooling. I like the idea of building a corner jig as well. Another concern is that I’m reasonably comfortable doing 1F, but I struggle getting a full 2F weld, although smaller sections with cooling time should limit blow through at the end? I do have a vent hole drilled (learned that lesson the hard way building tube bumpers a few years ago!).

[LtBadd]

although smaller sections with cooling time should limit blow through at the end?

The smaller the enclosed area the greater the risk of blow back, but the cure is the same, let it cool first then close it off.