Thread: aluminum arc welding

I used to work as a welder many years ago: mainly arc/oxy welding steel and brass with the occasional foray into aluminium welding with oxy. I just bought some aluminium arc rods with the intention of learning to use them with my CIG DC unit - didn't go too well though - just can't seem to maintain an arc. I know Tig is the way to go, but for the amount of aluminium welding I'd do, just can't justify the outlay. So any tips would be appreciated.

I am by no means and expert on MMA of aluminium, in fact I've never done it.
My understanding though is that DC electrode positive or reverse polarity as the yanks term it, teamed with a short arc length is the general setup of the process. I am also lead to believe that it is very touchy as far as power level goes. Lincoln Electric, in their book "New lessons in arc welding, second edition" spoke of the process at length, but I cannot find my copy and have not seen another for sale.
What electrode type and size are you using?
If you are having trouble holding an arc, then my two thoughts would be either a little more power, or quite possibly increasing your rate of feed as these electrodes are consumed rather rapidly as I understand it. These two approaches are diametrically opposed, so you will need to identify why your arc is extinguishing first, before you can correct the situation.
Keep us posted as this could be an interesting thread.

This guy, who looks like Cletus the Slack Jawed Yokel, had a go with them without much luck:
https://www.youtube.com/watch?v=dIIp3f7xV8g

I have used them about 40 years ago. From memory, high amps and they disappear in about 30 seconds. Was welding the lugs on the gearboxes of chain driven concrete mixer bowls. We had to heat the ally well and truly first though.
Kryn

Originally Posted by johnyjamtin

I know Tig is the way to go, but for the amount of aluminium welding I'd do, just can't justify the outlay.

Have you something specific in mind or was it just because you can? I have a friend who refuses to touch Al with a welder simply because he maintains that to maintain proficiency you need to do it regularly. If it was just a small one off I'm sure there is someone near who could throw some hot metal around for you.

Michael

You could find a cheap tig torch for your welder and a bottle of helium and try that ... apparently.

While you can weld ally using DCEP, it takes a fat electrode and a lot of amperage to get anywhere. I did it at a TAFE college once just for the heck of it. I think we hit the 3mm ally with around 160-170A, using a 3.2 or even 4mm electrode from memory and the weld was really wide - as you would expect from the heat input.
I can see a place for ally stick welding in a site/maintenance welding application, but there are a lot better processes overall. I seem to remember that the Lincoln bible also mentioned the use of the ally electrodes for oxy acetylene welding of ally as well.