Would acetylene's larger heated zone make it better than stick to weld
a tee joint in 1" square tubing that should be as square as possible?
The shorter leg will be the upright that planks are clamped against to
saw the top edge, so 'square' in this instance is to woodworking
tolerance and 'possible' means for a hobbyist.
Center tack and weld the flats first . Then center tack and weld the
inside corners a quarter at a time alternating sides . Good clamping
can't hurt . And small beads are going to pull less than big ones .
Don't you have a wire welder ?
That's what I thought. I bought the acetylene tank after the
blacksmithing class last year and haven't gas welded anything this
large yet, and want to try on something non-critical like this tee
that I can saw apart and do over.
Based on experience with similar square tubing joints on the sawmill
frame I plan to weld the outside flat joints but not the inside
corners, then grind flush and add triangular gusset plates.
The sawmill's open-ended ladder frame stayed straight until I welded
the rungs' inside corners, then cooling shrinkage pulled the outer
ends together and I had to jack them back parallel.
The ladder frame ends have to be open to install the bandsaw blade.
I once stick welded a 3/8" plate to another 3/8" plate, in a tee. There
was only inside corners & I was astonished how much the plate was bent
by the cooling weld. When you consider how little leverage the weld
has, the force has to be extreme.