Testing Alumium with diy spool gun

[Kram]

Would like opinons of my first alu welds. Aluminium seems much easier than steel but until today Ive had feed issues. No idea how much gas Ive used upfrom 110L bottle. Gas was set between 3-5LPM by pea shooter. Spool gun thread is in Sealey section if anyone interested, I recommend it, should be possible on any cheap mig.

Main difference for alu it needs gravity and torch held above work, otherwise wire balls up and wont jump the arc to the workpeice, looks like poo. Perhaps I need to swap polarity?

Alu doesnt blow holes very easily, but it will sag and bend, penetration is easy, flows much better than steel.

Some welds were black as if no gas or far too much power? but then Id have good welds without any changes, seems random (there was gas).
My 130 mig can blow holes in 2.5mm sheet then a large blob of molten alu made a hole in my gas hose so I stopped

I will need to weld caps onto the end of 3mm thick, 2.5" square alu tube. They are going to be lipo battery cases for an ebike project

 

[T0rnado69]

diy spool gun, Interesting, got any pics

 

[Kent]

Welds? I see no welds Seriously in my experience (and I haven't done it in a good long while) Ali welds super fast with mig but you need the right set up feed wise and you need to get the right arc to make the weld sound. Good spool gun or the correct rollers etc in a 4 wheel wire feed

 

[Kram]

Yes some pics here, http://www.mig-welding.co.uk/forum/threads/spool-gun-mightymig-130xt.52990/

I plan to improve it with a stepper motor and much smaller roller unit - the sealey one has a gearbox and is massive.

 

[Kent]

Yes some pics here, http://www.mig-welding.co.uk/forum/threads/spool-gun-mightymig-130xt.52990/

I plan to improve it with a stepper motor and much smaller roller unit - the sealey one has a gearbox and is massive.

The rollers have a great deal to do with it they must not crush the wire but must feed it fast and smooth as this stuff conducts electric so much better / faster than steel

 

[Richard.]

U shaped rollers for ally V shaped for solid steel and nurled for FCAW. As said above using the wrong shape will deform the soft aluminium wire before it reaches the contact tip.

 

[Richard.]

Polarity should always be DC + for ally mig. 100% Ar.

 

[Kram]

Yes Im using dc+ and 100% argon. Spool guns dont care about the roller, thats only to protect the torch liner which I dont have

So my pic of welds, any suggestions how to improve? or how to find the correct settings easier with aluminium?

Im going to start my lipo case, need to get settings correct for joining 2.5mm sheet to large pieces of 3mm thick tube. I think the end caps should be slightly smaller so the weld makes up the outside corners?

 

[backpurge]

Ali doesn't need gravity, the molten droplets are projected across the arc no matter what position you are in otherwise how could you weld overhead or vertical with it. You need to concentrate on getting consistent beads on plate before you move onto actually sticking stuff together. Generally aluminium is a lot harder to weld than steel but with plenty of practise you will get there

 

[Kram]

When it happens there is a blue glow where the argon gas arc is heating the work without any metal spraying onto it. The wire balls up inside the contact tip then falls on the floor. Im using 5356 wire if thats relevant. ~ 4LPM gas

It does not happen if I weld downwards with gravity. I do some more practise welds today.

 

[Richard.]

Yes Im using dc+ and 100% argon. Spool guns dont care about the roller, thats only to protect the torch liner which I dont have

So my pic of welds, any suggestions how to improve? or how to find the correct settings easier with aluminium?

Im going to start my lipo case, need to get settings correct for joining 2.5mm sheet to large pieces of 3mm thick tube. I think the end caps should be slightly smaller so the weld makes up the outside corners?

I'm assuming your using a contact tip!!!!!! And the hole in that contat tip is round. U shaped rollers are not to just protect the liner. They limit the deformation of the wire thus stopping a clogged up tip.

 

[Wendelspanswick]

When it happens there is a blue glow where the argon gas arc is heating the work without any metal spraying onto it. The wire balls up inside the contact tip then falls on the floor. Im using 5356 wire if thats relevant. ~ 4LPM gas

It does not happen if I weld downwards with gravity. I do some more practise welds today.

You might find that the spool is dragging when held in a different position?

 

[Jim Davey]

Drive roll is important on anything, you'll find this out as you do more work.

 

[Jim Davey]

When it happens there is a blue glow where the argon gas arc is heating the work without any metal spraying onto it. The wire balls up inside the contact tip then falls on the floor. Im using 5356 wire if thats relevant. ~ 4LPM gas

It does not happen if I weld downwards with gravity. I do some more practise welds today.

This is a classic loss of feed, could be slipping rolls or a siezed tip or both.

 

[Kram]

No its still feeds fine, and I get a puddle of molten alu on the floor (which melted through my gas hose!). I'd try to get a video of it but not sure if it would damage my camera?!

 

[Jim Davey]

It's not feeding fine if the arc goes all long and wire falls in blobs on the floor. Or your wire feed is just too slow for the voltage selected.

 

[Kram]

Ill get video of it then. I did try turning the feed up, just got a lot more mess on the floor. Its like the wire melts and is pulled back to the tip. Im also max wire speed when doing 2.5mm sheet - so need to upgrade the feed unit soon.

I dont get these problems welding downwards, so its not too bad. I wasted quite a bit of gas trying though.

 

[Jim Davey]

It's accepted practice to go up a tip size or use special ally dedicated tips to help avoid this issue.

 

[Kram]

Gas seems an issue, with a new bottle fully open I was getting ~ 5lpm and has dropped to 3-4lpm, 5lpm seems to be the minimum to get nice welds. Ive not got any leaks.

Had to file the welds down on the big bit, looked horrible. I might cut them out and redo after Ive done the other 3 pieces. Not sure I should order more gas, might get a big bottle.

 

[Jim Davey]

I don't think you have too much of a gas problem there. The welds are bright and the sooty deposits are at the sides, this is normal for magnesium alloy wire. I'd say you could use a little more than gas you're using but you're on the right track.