Thread: MIG Welding Aluminium

just went a head and purchased a MIG welder with spool gun for welding aluminium cant complain for the price though, ill try weld the 1.6mm sheet if not successful ill buy a 3mm sheet of aluminium

next is to buy a cheap BOC MagMate 200A DC TIG to practice my TIG welding on steel

What MIG did you buy?
Playing around with fuel tanks can get out of hand really quickly. Not a good project to experiment on. Using a mig to spot the panels together will probably leave lots of leaks, so at the very least, make sure you thoroughly leak test your tank, (about 3psi of air and soapy water on all the fittings, welds and seams).
Without being rude, you are probably trying to punch above your weight at this point fabricating a fuel tank out of ally.

i bought the LOTOS MIG from ebay with spool gun for $450, other option i was looking at was UNIMIG 180A mig with spool gun for $650

cant complain for $450 really, came with a bunch of accessories including a regulator which i think was my downfall when i was AC TIG welding aluminium

Sorry to say Gazza, but I think your heading down the same track as you did with the tig. I don't see this machine being very successful for aluminium.
The tig work you were doing was improving every time with a bit of practice. You should of held out and saved for a token tools or everlast machine.

Originally Posted by cwcarter

Sorry to say Gazza, but I think your heading down the same track as you did with the tig. I don't see this machine being very successful for aluminium.
The tig work you were doing was improving every time with a bit of practice. You should of held out and saved for a token tools or everlast machine.

ill see how the MIG/spool gun goes it should work i dont see why it wouldnt its designed for welding aluminium

i was looking at the everlast a few days ago and they have sold out of the 185A micro AC/DC TIG they also jacked the price up to $1000 now, so i searched ebay and found the older model everlast on there dressed in blue for i think it was $760 delivered if the spool gun fails to do what i want it to do ill buy the everlast copy

Unfortunately Gazza, I have to agree with CWCarter.
Your regulator may have been part of the problem with your tigging, but I recall your shrouds being too small and a heap of other issues that we were working through through. Honestly, I believe you are setting yourself up for failure here. 1.6 ally takes a damn good mig welder (pulse) and a good welder wielding the gun to have any degree of success. It's not the easiest with a tig either, particularly for one who is learning still.
Not everything said on Ebay is true either. That welder has got an abysmal duty cycle and will be very expensive to feed with the little spools.
If you tallied up the money you have spent/lost so far, you could have bought a decent welder, either Mig or Tig and be fabricating happily. I didn't see what consumables the gun uses, but I hope they are readily available, because you will go through a few, particularly while learning.
Sorry If I seem negative, but this seems like history repeating.
Anyway, once you get the welder, we'll see how it goes I guess. Have you got an Auto Shield? Probably worth getting one now if you don't and try to round up some 5 or 6mm scrap to practice on before you tackle 1.6 or even 3mm sheet.
Before you begin your tank build, better run your design past the forum as there are some traps to beware of.

from what i got from self teaching my self to TIG weld aluminium is u need a lot of patients and at $88 a bottle of argon i didnt have much patients i was chewing thru bottles like no tomorrow, the problem with my regulator is i accident knocked over the cylinder and the regulator took a graze to one of the meters i think it was the flow meter

i can weld 3mm aluminium no worries with the TIG as pictured below its just the bummed regulator and 1.6mm plus a non variable amp setting all contributed to my unsuccessful attempt at welding my last piece of art work

first weld is 5-6mm steel corner weld second is aluminium 3mm corner weld so i can say i learnt to TIG weld although not the best and i cant get rid of the contamination, i was watching a video on youtube last night of mig aluminium welding wire that cleans the oxide off as it welds u dont even need to brush the aluminium do we have a similar spool here in australia?

Picture 023.jpgPicture 025.jpg

Those TIG welds were starting to get there, particularly the 3mm Ally.
If such a Ally mig wire exists, I've never heard of it. What I reckon they were talking about is the normal cleaning of the oxide by the Mig process.
Electricity flows from the negative to the positive pole. What this means for you is that the current flow actually lifts the oxide off and allows the weld to progress on clean base metal, assuming of course that your gas shield is doing its job and keeping the atmosphere away. This works well on clean ally. By clean, I mean new ally plate and extrusions. Add anodising, salt, paint residue or other external contamination, even heavy oxide build up from weathering and it all turns to poop and you have to wire brush or grind the material first.
It would be fair to say that TIG will handle dirtier material than MIG because you can hang around a bit and let the arc clean the base metal before moving forward again.
Don't scrimp on the gas when you MIG ally either. Around 20LPM is what you will be looking at - roughly 2 1/2 times your flow rate with TIG, but don't worry, you will be welding 2 1/2 times quicker as well, so it all balances out.
If I were to sum ally MIG up, I would say. Clean material, turn your welder up hot and get in and out again as quick as you can. Where you can hang around and "work" the bead with steel, ally likes heat and fast travel speeds.

thanks karl, here is a video showing what i think is the same welder being sold in the US also scroll forward to 8mins 40sec the spool gun section it shows what i meant in one of my earlier post how u just weld a dot and join the dots together to look like a TIG weld this is how i am going to weld my tank and other pieces together

https://www.youtube.com/watch?v=bt7Niz5iP2M

the welder arrived about 40mins ago and i got stuck into it strait away, the picture with 6 beads is using the recommended setting on the chart but the chart says 3.2mm im using 3mm

played around with a few settings and got these results, looks like the metal is heating up to much what do u guys think?

any mig spool gun welds i done are center of each pic Picture 015.jpgPicture 016.jpgPicture 010.jpgPicture 011.jpgPicture 012.jpgPicture 013.jpgPicture 018.jpg

forgot to add im using the spool of ally wire that came with the welder which is 4043

i turned the voltage down two letters and kept the same wire speed and this is how its welding looks ok now, i found i cant run beads it eventually melts thru but doing spot welds it works great

Originally Posted by gazza2009au

i turned the voltage down two letters and kept the same wire speed and this is how its welding looks ok now, i found i cant run beads it eventually melts thru but doing spot welds it works great

Gazza, do you see those little dots in the center of every spot you have done? Chances are that you will get a leak from every one of them. The little dots are caused by the area of metal that cools last "sucking back" and shrinking. Generally this leaves a tiny fracture in the material that causes leaks in tanks.
Looking at your previous welds, they seem very dirty. The finished mig weld should be clean and shiny with black smoke residue next to the bead, but not staining it. A wipe with a rag should remove this smoke unless you leave it overnight in a damp environment, then it sets on the plate. What's your gas flow rate set at? Sometimes dropping your gun angle will also clean the bead up.
To be blunt. If an apprentice of mine ever handed me a weld like the one shown in the youtube video, they would get it handed right back to them and be told to go away and do it properly. There is no justification for that approach as it will produce a weak weld on Aluminium with very poor fusion and frankly, it looks like crap.
My best advice to you is to go back to basics. Start running a few beads on 5 or 6mm material. Once you get a feel for the welder and material, drop down to 3mm. Remember ally likes power and speed, so you will probably be using a bit more power than you expect on 3mm. You cannot really drop your power too much in the hope of slowing down your travel either.
For an inexperienced ally welder, 3mm is a challenge and 1.6mm is best not attempted. You will find that lap and fillet joints will be easier and more successful for you than butt or corner to corner joints. 4043 wire is not really the correct wire for the grades of material you will be working with, but will not hamper you too greatly.
There are some really good youtube videos, but also some shockers that spread misinformation and hamper your efforts. Try this video. I personally prefer a little more wire than him, but this is a fairly good snapshot of what you are after.
http://youtu.be/8AT4cEHtMn8

Originally Posted by Karl Robbers

Gazza, do you see those little dots in the center of every spot you have done? Chances are that you will get a leak from every one of them. The little dots are caused by the area of metal that cools last "sucking back" and shrinking. Generally this leaves a tiny fracture in the material that causes leaks in tanks.
Looking at your previous welds, they seem very dirty. The finished mig weld should be clean and shiny with black smoke residue next to the bead, but not staining it. A wipe with a rag should remove this smoke unless you leave it overnight in a damp environment, then it sets on the plate. What's your gas flow rate set at? Sometimes dropping your gun angle will also clean the bead up.
To be blunt. If an apprentice of mine ever handed me a weld like the one shown in the youtube video, they would get it handed right back to them and be told to go away and do it properly. There is no justification for that approach as it will produce a weak weld on Aluminium with very poor fusion and frankly, it looks like crap.
My best advice to you is to go back to basics. Start running a few beads on 5 or 6mm material. Once you get a feel for the welder and material, drop down to 3mm. Remember ally likes power and speed, so you will probably be using a bit more power than you expect on 3mm. You cannot really drop your power too much in the hope of slowing down your travel either.
For an inexperienced ally welder, 3mm is a challenge and 1.6mm is best not attempted. You will find that lap and fillet joints will be easier and more successful for you than butt or corner to corner joints. 4043 wire is not really the correct wire for the grades of material you will be working with, but will not hamper you too greatly.
There are some really good youtube videos, but also some shockers that spread misinformation and hamper your efforts. Try this video. I personally prefer a little more wire than him, but this is a fairly good snapshot of what you are after.
http://youtu.be/8AT4cEHtMn8

just watching the video at 4:50 he shows a low wire speed and very high volts my chart is showing just over 50% volts and almost maxed out wire speed

wouldnt low wire speed and high volts cause burn back?

Gazza, you must be a very patient person. Keep at it and you will succeed.
Karl, if I may... try to keep advice on welding constructive, what you would say to a hypothetical apprentice is best left unsaid.