Thread: Arc welding alloy tube.

I have been doing some reading.
Perhaps this would be better.
Boswell 200Amp AC DC Inverter TIG ARC Aluminum Welder | eBay

K

Hi Keith, I'm not a welders backside, but have been lucky to work with a couple of brilliant welders over the years.

I can braze till the cows come home, and am passable at oxy welding, if I've been practicing but I've mostly had access to brilliant welders, the type of blokes that make those incredibly neat, even TIG beads that look more like art than an industrial process of joining metals.

DC TIG's are great for steel and particularly stainless, especially if it has an adjustable pulse setting.

Yes, I am just a farm welder using stick and gas fusion.
Reading up on TIG as I would like one for thin ally and it seems you need AC for it cleans up the ally as it goes. Not so much need for the SS wire brush.
That last I linked to seems OK and I was just asking for comments.
Not meaning to hijack the thread but the discussion I hope will help the OP.

K

Originally Posted by 123rover50

Say for welding from .5 up to 2mm ally sheet, what would you reccomend?
What are inverter DC TIG,s good for?
What about thishttp://www.ebay.com.au/itm/NEW-ROSSI-Welder-Inverter-Plasma-Cutter-4in1-Welding-Machine-AC-DC-TIG-ARC-Stick-/160861426342?pt=LH_DefaultDomain_15&hash=item25741 692a6


Keith

sikaflex.....if you're just bonding ally sheet to a frame a nice clean joint and a bead of that stuff with good clamping while it cures...

Im keen to give some of these a try. Not on a roof rack maybe unless it had lots of bracing.

[ame]https://www.youtube.com/watch?v=yqkceLrH9Ao[/ame]

[ame]https://www.youtube.com/watch?v=CJ42scaWFnw[/ame]

Dave

As that second vid says, it's actually hard brazing, not welding.

I've brazed aluminium, you need the right flux and the heat is directed by capillary action, if the flame hits the flux it oxidises and it's game over.

You can fusing weld aluminium with an oxy/acetylene blowpipe, I've seen it done and it looked just like a MIG bead, again you need special flux and picking the puddle before it collapses is an art.
Ideally you use a special lens in your welding goggles too, again so you can pick the puddle before it all goes ta ta's.

Yes I use Sikaflex like that a lot, but I was meaning edge to edge.

Woops, I should have quoted Blknight.
Its in reply to his post.

The reason you need to use AC for welding aluminium is that the aluminium oxide melts at a much higher temperature than aluminium metal.

The AC pulsing/swinging from +ve to -ve burns the aluminium oxide from the surface of the metal allowing it to be melted cleanly and at a far lower temperature than if the oxide remained on the surface. This works even better with an argon shield which prevents the molten metal re-oxidising whilst welding.

That is why TIG or MIG are the preferred methods for welding aluminium.

Arc welding rods need to their flux to prevent oxidisation of the molten metal.

As mentioned previously by Rick, it is possible, but difficult, to oxy acetylene weld certain types of aluminium if you clean off the aluminium oxide, flux and then immediately weld it (usually cheap grades of alloys as you would find in teapots etc).

Certain series aluminium alloys are more weld-able than others. From memory all of the 1000 and most of the 4000, 5000, 6000 and some of the 7000 series alloys are readily weld-able.

Always use a stainless steel wire brush to clean your material when welding aluminium.

Hope this helps