yes
If the seam is coming apart, use J B Weld between the parts and then if possible screw in 2 small self tapping screws through both parts at each end. This should pull the parts together, then finish off the top of the seam with J B Weld also.
seam welding is a process that produces a weld at the faying surfaces of two similar metals where its used depends on which metal you look to weld
seam less pipes are having with out weld but produced by extension process it is costly than seam
You can arc weld & then the flux will be in the rod.
That would depend entirely on where you take it to be repaired.
You get plexiglass/perspex glue . -Weld On #3 , #4 or #16, depending on how tick you want the seam to be.
In a fillet weld, the leg and size are the same for the convex weld.
The clue is in the question! If you weld a seam, or a spot which do you think is stronger? Take the example of the ordinary household radiator, it is seam welded, and they are usually watertight, it would be hard to make a waterproof seal with a spot welder and if you did try you would find it is very slow. A seam welder uses two rollers as the contacts instead of the copper rods, the rollers are inevitable faster as they can move along the piece easily and you get a perfect seal or seam when done, excellent.
Jb weld expoxy mix
It may work as a temporary fix.
I doubt very much it will hold.
weld it with nylon rod using iron plastic welder.