Bob-
Tig welding of bandsaw blades mostly leads to heartache…The very localised hot line of weld ends up very brittle, inviting a re-break. The usual blade butt welders leave the blade in the same state, but said welders have an annealing function to bring the blade weld zone back to usefullness. You would need to anneal as well – gas torch flame, etc…
Some folk have good results silver-soldering blades.
Colin -Welding steel ( and stainless) with tig is quite easy with the small sub 10kg welders – depening on metal thickness and weld length. Its all a trade off – those machines have at best a 20%, maybe 30% duty cycle at mid-amperage range. For 1mm steel and a dozen weld runs exceeding 100mm, thats fine – @ 60 to 80amps, it will do well.
4mm steel, you might get away with a dozen 30mm welds @ 80 to 100amps – 120amps better
Aluminium @ 2mm, you need around 100amps min and fast travel – 6mm Aluminium you need around 150amps for good penetration, and those welders will at best do maybe 3 or 4 100mm welds – some I have tried died doing that..
Aluminium is a different game – you need lots of amps as the material conducts the heat away very fast. Pre-heating the job does help.
Some 2mm sheet bent into boxes and tig welded – no preheating, 140amps, travel around 5 to 8mm /second.
in Aluminium, going slower does not often help – the material conduscts all the heat away quickly, and then the job saturates, all gets very hot, and while you are taking you time at the weld face, the whole wall sags away..you cannot see when aluminium is about to melt!
Also, joints must be good and tight!
If you are serious about ease of use, lack of frustration ( welding aluminium will frustrate you enough, let not the welder do so as well!) – then don't buy 'cheap'…
Joe



