My aluminium welding quest - Mig

Tiggy_dorset · Apr 6, 2012

I bought an Aluminium framed workbench/table from a forum member about 6 months ago. Its a little too large as it is for my workshop, so I decided it needed cutting down to produce a smaller bench and a mini mobile bench that I can sit at to do small scale tig work.

I bought a small reel of ali wire and set to work.

Sealey 150amp
0.8 ali mig wire
1.0 tip
metal liner
Pure Argon gas
Power set to max
Wire speed (pretty dam fast)

Box section 50x50x2.5 (if i remember right)

A few problems with birdnesting at the wire feed as expected, but managed to get by with my setup. If I was do be serious about mig welding ali on a regular basis, I would use a wire feed gun, teflon liner and a knurled roller without a doubt. Too much wasted time and wire due to birdnesting with the current setup, although its still possible for those wanting to try it out.

It was definately a learning curve. Now I have a bench to work on instead of the floor, I should make a better job of welding up the smaller table :whistle:

A few piccies for your amusement :laughing:

Lawnmowerboy · Apr 6, 2012

I think they're some of the best aluminium mig welds i've seen

well done!

@Turbo · Apr 6, 2012

first attempt is pretty solid looks well. did you test it for strength?

I usually get carried away with testing myself and end up with a buckled mess lol.

Tiggy_dorset · Apr 6, 2012

cheers guys. I didnt really do a strength test so to speak, unless standing on the bottom shelf bars constitutes as a weld test, whilst only being held with tacks and one weld bead each :whistle:

200T · Apr 6, 2012

I'm not that good with mild steel

Wozzaaah · Apr 6, 2012

They're neat but there's a heck of a lot of cold lap on some of them, pic number 3 shows it very well, it doesn't look like the lower leg has fused at all.

Still plenty good enough for a bench and far better than my awful attempts, well done. :clapping:

Tiggy_dorset · Apr 6, 2012

Wozzaaah said:
They're neat but there's a heck of a lot of cold lap on some of them, pic number 3 shows it very well, it doesn't look like the lower leg has fused at all.

I do agree, There does seem to be some air gap there. I am thinking my machine is very slightly underpowered for maybe that thickness material. I was trying different weaving patterns and different travel speeds to find a way of best penetration.
I get the impression Aluminium mig wire doesnt go down to 0.6mm?

Maybe preheat the joint with a propane torch before welding it?

shenion · Apr 6, 2012

Aluminum MIG starts cold. It gets better as the metal heats up. That looks like the issue. You can start with a short torch/work gap at the start and them move to a normal one. Difficult to do without getting the wire stuck.

0.6mm aluminum would be flimsy as string

Would definietly require a spool gun. I have only seen 0.8.

Tiggy_dorset · Apr 6, 2012

shenion said:
Aluminum MIG starts cold. It gets better as the metal heats up. That looks like the issue. You can start with a short torch/work gap at the start and them move to a normal one. Difficult to do without getting the wire stuck.

0.6mm aluminum would be flimsy as string Would definietly require a spool gun. I have only seen 0.8.

Makes a lot of sense judging by the difficulty I had getting some decent tacks initially.

F.J. · Apr 13, 2012

Tiggy_dorset said:
Maybe preheat the joint with a propane torch before welding it?

I Mig pulsed a aluminium tipper body on a Class C wagon the other week and found it welded alot neater once id pre heated the surface first. Brilliant first attempt by the way :clapping:

Tiggy_dorset · Apr 13, 2012

F.J. said:
I Mig pulsed a aluminium tipper body on a Class C wagon the other week and found it welded alot neater once id pre heated the surface first. Brilliant first attempt by the way

Thankyou for that. My spool gun may arrive tomorrow

so hopefully some better results are due this weekend. Pics to follow :cool:

Tiggy_dorset · Apr 20, 2012

A little update :

A big thankyou to Windy Miller for selling me a spoolgun and posting it with great speed.
I have spent the week on and off wiring a new socket for my new spoolgun and a switch to allow me to alternate between the machine/gun feed motors.

I finally got to have a play today and am impressed with the difference. A smoother feed, no worries at all about birdnests leading to wasted time and wire, ability to move around faster as you dont have to worry about whether the torch leads are straight/kinked. Overall, the benefits lead to a stress free experience.
If you are attempting Mig Aluminium, I highly recommend a spoolgun.

Below is a pic of my test runs whilst setting up the machine.
power max - 150 amps
wire feed setting number 6
0.9mm wire
1.0mm tip
gas pure argon
50x50x4mm box section

Interestingly, at max power I acheived massive penetration on 4mm box, (too much even) so had to move fast. On my previous setup I occasionally produced a good looking weld but lacked decent penetration.

Below is the only half decent pic of a butt weld. All other pics on my phone came out blurred.

Seano · Apr 20, 2012

So, I guess after a bit more practice with the spool gun you can class this as a success then tiggy.....

Tiggy_dorset · Apr 20, 2012

Wheelchairwelder said:
So, I guess after a bit more practice with the spool gun you can class this as a success then tiggy.....

I could live with calling this a success :cool:

Iam now pleased and comfortable with the setup. I now have a good foundation to practice and improve my technique with various joints. Now I have decent workbenches to work on, I cannot use the excuse that i was working on the floor which led to a poor weld :whistle:

I am looking forward to more practicing once I get some more material.

Tiggy_dorset · Jun 19, 2012

Spool heater

Has anyone ever used one of these spool heaters?

http://www.r-techwelding.co.uk/Welding_Consumables/Mig_Wire_Aluminium/mig_wire_spool_heater_pad

I would have thought that cold starts, for example, would be mostly influenced by material temperature rather that wire temperature. would wire temperature make a noticable and worthwhile difference?

Cheers.

Seano · Jun 19, 2012

A really interesting bit of kit that , and not horrendously expensive either.

Sub-arc · Jun 19, 2012

I wonder would a run on plate help here ?

As per (terrible) :laughing:

drawing. Break/cut off plate when finished the weld.

[when I resized that to upload I made a nuts of it. But you get the idea]

Tiggy_dorset · Jun 19, 2012

Sub-arc said:
I wonder would a run on plate help here ?

As per (terrible) drawing. Break/cut off plate when finished the weld.

[when I resized that to upload I made a nuts of it. But you get the idea]

Interesting idea. I cannot see why that wouldn't work in theory (although aly welding is still new to me), as long as the extention plate is making good surface contact with the workpiece to allow adequate heat transference. I suppose it will depend on the job itself whether its more practical to use that method or just to preheat?

Paul. · Jun 19, 2012

Run on and run off plates are a common technique , usually tacked to the job then broken off afterwards, it lets you have the arc fully established before you hit the joint proper, and eliminates the crater at the end of the run, best to set up the plates as a proper extension of the joint, copy the prep etc so that there is no transition between the run on plate and the job.

Frosty · Jun 20, 2012

Preheating the spool is very strange to me.......you need the heat in the material for good penetration not the wire. Maybe here in the west we got it all backwards?! It wouldn't be the first time!

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