MIG welding aluminium
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If you need any pieces of ally to practice on...give me a shout Paul

well, for my first proper bit of ally tigging my plenum/ manifold came out ok considering i was learning as I went,

the best bit of advise i can give (apart from keep everything clean) is plan ahead so you avoid any tricky to weld areas, I found the bits i overlooked and had dificulty welding took up far far more time than the long runs. and also try to do a weld in one hit wherever possible.

seems a daft comment....but get in the most comfortable position possible. Pays dividends with welding.

Do you recommend using the foot pedal?

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

I prefer not...but some people do

I couldnt get on with the pedal either, was a bit like rubbing you tum and patting your head.

I just set a longish slope (1-2 sec) which tbh you seem to need any way to avoid a crater, and pulsed the triger on and off to vary the power.

If you use Tig then I would agree, if your using a smaller Mig think mines is 100-120 A it certainly helps as the 5mm plate I did had poor pentration at the start of welding but once I had done a bit and got the whole job up to temp it went alot better, this was on my light weight Alternator bracket I made, now replaced with far more relaible steel one, Ally bracket failing at where I had started the welding where it had good pentration it was fine just that inital starting area had poor pentration and cracked due to all the heat going into warming up the part. There are ways to warm larger items with an induction heater i think, as a friend was talking about doing this on a gearbox he needed to mig a crack up on when I mentioned preheating, It is also recomened to warm up some steels before welding especially if its the middle of winter to normal room temp to promote better quaility welds

WEST

Got A GTM With A Honda In the Back, and huge Nitrous bottle where the passenger seat should be when racing!

Edited by Rod S on 16th Apr, 2009.

Schrödinger's cat - so which one am I ???

last manifold i made was a steel plate ,16guage zinc plated one for a v8 with a divider throught to give seperate flow to each pair of cylinders across the v .ugh!! all welded edge to edge .blimen fun ....not!

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Schrödinger's cat - so which one am I ???

Bit like SidewaysGTM, I've had a reasonable amunt of success using MIG on ali. To my amazement really as I thought I'd give it a go one day.

Made quite a few smaller pieces for the van like the actuator bracket, mods to Maestro plenum, turbo oil feed take off from filter head, threaded boss and expansion tank stub into cast ali thermostat housing.

All seems ok with the weld quality as long as you dont mind doing a bit more cleaning up with a die grinder suitable for grinding ali - the burr is MUCH coarser - about 6-8 teeth as opposed to 20-25 of a typical steel burr - certainly more clean up than steel MIG welding. Anti spatter spray also works well on Ali

When I MIG ali, I use my standard 120A Clark Turbo MIG (fitted with Nylon liner and standard .8 mm copper tip) but replace the large Argoshield gas bottle with a small bottle of Argon from Halfords (about £8 the last time I was in the shop) and my 0.8mm steel wire comes out and is replaced with a small 0.8mm roll of Ali wire, again from Halfords (about £9).

All in, it cost me about £20 to get started which was fair game if it went Pete Tong. However, like I said, good success.

I turn up the wire speed to about 50% faster than I use on steel wire and start with a fairly low current, gradually increasing the current to give optimal penetration. You can tell when it's on song - sounds just like TIG.

I found pre-heat is essential by trial and error - it greatly improves weld quality.

Takes about 15 min to convert the welder and have a practice then I'm off.

Attached is a shot of a Maestro plenum which I've added a completely repositioned inlet pipe, a dump valve stub and an elbow into the inlet from the intercooler.

For some reason, it seems to work even better with the crap ali cast stuff that thermostat housings are made from.

If you wanna see the weld quality, the parts are in the engine bay on the van if you next catch me at a show.

Hope this helps.

Richard.

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Minivanless, but reluctantly happy living with the decision. There'll be another one day.
http://www.youtube.com/profile?user=minimadmotorman#p/u

Looks really good in that photo.

I'm now 99% certain my problem was the steel liner, probably made worse by the nature of a Eurotorch having a longer hose and liner.

When I went to rewind the wire to disconnect the torch and get the liner out, it was noticably tight to feed out, much tighter than when I had fed it in the previous day. Obviously down to all the aluminium "dust" that the steel liner had been shaving off the wire.

I shall find out as soon as the new teflon liner arrives.

Schrödinger's cat - so which one am I ???

Any news on the performance of the teflon liner?

I'm keen to try this method with my inlet manifold.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Sorry, I forgot I said I'd report back.....

Teflon - brilliant, wire feed problem just went away.

I haven't actually done any serious welding since, just a couple of test runs but no feed problems and no more wire burning back and sticking to tip.

I did deliberately use the MB25 tip though (machined back to the same length as an MB15) as the teflon liner touches the back of the tip so I wanted to minimise heat transfer to the liner.

Schrödinger's cat - so which one am I ???

Thanks, I'll get the extra kit and wire on order.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Don't forget, whether you use an MB15 or MB25 tip, you need to get it for 0.8mm wire, not the usual 0.6mm as the smallest alloy wire is 0.8mm

Schrödinger's cat - so which one am I ???

Glad someone was able to learn from my mistakes.

Trial and error is always better when someone else does it!

Schrödinger's cat - so which one am I ???

Just to follow this up...

I dismantled the MIG just now to swap back to mild steel (a shell to repair now the engine runs) and found this on the teflon liner


It's nothing serious but just shows how much heat goes backwards... I was using an 25 tip (my torch only needs a 15) and 8l/min argon.

Schrödinger's cat - so which one am I ???

A year on but.....

Did some more aluminium with MIG last week, 57mm 1.6mm wall intercooler pipework - decided to try MIG again as TIG takes ages on large diameters or long runs.

Got all the settings about right, first time doing 1.6mm and large gaps with MIG and then the wire ran out.....

I'd bought a new coil last year in anticipation, fitted it and total disaster....

Wire sticks to tip on startup and inevitable birds nest at feed rollers.

Tried many times, same result - but I had been welding fine for 15mins before.

Answer - I had bought 4043 wire because I use 4043 TIG wires - the coded welders at work had allways given me 4043 TIG wires to use for homers as they are 3-5% silicon and great for general purpose and castings (which are usually silicon alloy).

However, is very soft and has a lower melting point so when the wire trys to accellerate out of the tip it melts faster and burns back to the tip and the rollers birdnest it accordinly as it is so soft.

5356 is the better alloy for MIG wire..... magnesium rather than silicon.
Harder so doesn't bend and birdnest and higher melting temperature so won't burn back to the tip so quick.

A new coil of 5356 just arrived in the post so I'll hopefully be back to what I achieved five days ago, tommorow.

Schrödinger's cat - so which one am I ???