look on FB or your local sales sites. might could find a nice piece of plate for cheap. 3/8" is great, 1/4" will work. 3/16" will work if you clad another surface but it won't give you much spine to clamp to alone.
in my old garage i had a plate mounted on hinges to the wall, with a pair of drop down legs, when not needed it would fold up against the wall.
a roller stand can be handy for longer projects that extend beyond your surface. i may even have a roller and a couple tabs buried around here somewhere if you wanna make your own. i'll look around.
keep your eyes open for a chunk of copper, i have 1 about the size of a bic lighter it's great for plug filling old holes or joining sloppy cut corners. weld doesn't stick to it well.
find a couple pieces of old pipe and weld them to a small scrap plate, you can tack or camp it close to your work area to hold your gun and welpers.
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