MIG welding Ali

[mud90mike]

Hi All

Apologies in advance for what might be a stupid query

I know you can mig weld Ali and was wondering if I had the right setup to do so, I have a portamig 235, ali wire and pure argon bottle, reading through the forum lots of people say make sure the polarity is right, that its running on DC but I don't even know if my portamig will do this?

Thanks in advance for the help.

Mike

 

[wyn]

I use a kemppi mig for aluminium now and again, i don't change polarity. Changing polarity is more for gasless wire.

As you say use pure argon and a plastic/teflon liner instead of steel for the torch.

 

[mud90mike]

When you say liner which part do you mean?

 

[pedrobedro]

When you say liner which part do you mean?

The liner in the cable from the welder to the torch, like a long coiled pipe cover that you thread the weld wire into. Steel ones drag the wire and cause jams you need a fast feed and higher power setting for aluminium.

 

[mud90mike]

Ok, didn't even realise you could change that. Is it easy just to buy another torch and cable with plastic liner than change everytime?

 

[doubleboost]

This should help

 

[mud90mike]

Thanks

 

[Richard.]

Hi All

Apologies in advance for what might be a stupid query

I know you can mig weld Ali and was wondering if I had the right setup to do so, I have a portamig 235, ali wire and pure argon bottle, reading through the forum lots of people say make sure the polarity is right, that its running on DC but I don't even know if my portamig will do this?

Thanks in advance for the help.

Mike

DC +(heat at the electrode) for Ali mig so put your earth return in the - , 100% Ar gas as you have. The liner required is a Teflon liner stops the wire shaving and causing blockages and feed issues. U shaped feed rollers are required to stop deformation of the soft wire so it stays round and avoids problems at the tip. A short guide between the rollers helps a lot too as the wire is so soft it only takes a little glitch and your making slinky's at the feed rollers. I personally suggest as short a torch as possible 3m is good and keep it as straight as possible. If it's feasible to take all the above steps then it will help you out loads.

 

[Rrunnach]

For example, if you are using 1mm wire, install a 1.2 dia tip.....

 

[pedrobedro]

I bought a 360 amp migatronic torch to shorten for my old welder to use on aluminium, it's still in the shed as I sold the welder

For example, if you are using 1mm wire, install a 1.2 dia tip.....

That's why I bought the big torch setup to run bigger tips but it never got used.

 

[mud90mike]

DC +(heat at the electrode) for Ali mig so put your earth return in the - , 100% Ar gas as you have. The liner required is a Teflon liner stops the wire shaving and causing blockages and feed issues. U shaped feed rollers are required to stop deformation of the soft wire so it stays round and avoids problems at the tip. A short guide between the rollers helps a lot too as the wire is so soft it only takes a little glitch and your making slinky's at the feed rollers. I personally suggest as short a torch as possible 3m is good and keep it as straight as possible. If it's feasible to take all the above steps then it will help you out loads.

There is only one connection for the earth on a portamig: http://www.weldequip.com/portamig-hd-mig-welders.htm so is this one not capable of doing it?

Thanks

Mike

 

[Richard.]

Yes it is. Use that connection.

 

[gordon stephenson]

A spare torch with a different liner is always a good idea, but you want a teflon liner not plastic.

 

[Jim Davey]

The liners are plastic impregnated with Teflon. You can't run a plastic liner all the way to the tip on an air cooled MIG torch as it will melt, you need a screw on brass neck liner for the last 6" or so.

 

[gordon stephenson]

Hi Jim, Never ever done any ally mig, How does the 6"brass liner end deal with the swan neck bend on the torch?

 

[Jim Davey]

Just fine, it's coil wound just like an ordinary steel liner, except it brass and it has a collet crimped on the end that you screw onto the end of the plastic liner if it didn't come pre-fitted.

 

[Richard.]

For example, if you are using 1mm wire, install a 1.2 dia tip.....

A lot of people do use the next size up for Alu mig and usually the reason behind it is because they are using standard solid wire rollers so the Alu wire gets squashed and struggles at the tip.
The idea of a contact tip is to make good contact. I use 1mm tip for 1mm Alu wire and because I also use all the correct parts as I listed above It works well. I'm a firm believer in if your going to take something on board that's difficult to do Then invest in the best stuff to stand a fighting chance.

 

[Richard.]

You can get contact tips specifically for aluminium which make perfect contact but don't cause issues when the wire expands under heat. I've not used them personally but again I would look into it if it's going to improve my chances.

 

[Rrunnach]

I have and use proper Lincoln Electric supplied al/al rollers, tips are supplied by LE and, they recommend that extra tip clearance to allow for wire expansion = potential drag = potential burn back, 0.2 clearance will not reduce wire to tip contact. Standard whip used.

My own single phase Cebora Jaguar 2000, for al/al, spool and gun used, this too, has that extra clearance, which is a manufacturer recommendation. In fact, have always used larger clearance tips when mig welding al/al, this has never affected weld quality and integrity.

 

[Rrunnach]

You can get contact tips specifically for aluminium which make perfect contact but don't cause issues when the wire expands under heat. I've not used them personally but again I would look into it if it's going to improve my chances.

You will find specific tips you mention, have extra clearance.