Mig welding aluminium

Welding Techniques, Theory, Machines and Questions.

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Downwindtracker2
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Re: Mig welding aluminium

Post by Downwindtracker2 »

Thank for the encouragement, the battery box for the travel trailer is welded back together. There are even sections that look OK. I switched to .030 wire, that helped. And ended up using most of a tank of argon. I found the .030 wire easier to get a bad start, so used a couple of packs of tips.
A man of foolish pursuits, '91 BusyBee DF1224g lathe,'01 Advance RF-45 mill/drill,'68 Delta Toolmaker surface grinder,Miller250 mig,'83 8" Baldor grinder, plus sawdustmakers
rustyh
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Re: Mig welding aluminium

Post by rustyh »

I bought the same gun awhile ago but have yet to use it. If I remember the instructions correctly they say to keep the gap about 3/4" away and "spray" the arc. I'm going to get the tank and argon in the next month, so was curious if you found the instructions to be correct.
Carm
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Re: Mig welding aluminium

Post by Carm »

steamin10 wrote: (snip) Argon is hotter than Helium. (snip) .
Think you got that bass ackwards
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ken572
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Re: Mig welding aluminium

Post by ken572 »

Carm wrote:
steamin10 wrote: (snip) Argon is hotter than Helium. (snip) .
Think you got that bass ackwards
Good catch on that Carm.. :wink:

I agree, All of the Tig work on Aluminum I did back in the day was
with AC, and High Freq Set Continuous, and 100% Helium.

The Stainless Steel I did back in the day was 100% Argon, with DC, with the High Freq set ot Start.

With that said, my son was telling me a couple weeks ago that they have some good mixes of gases now.
He said he didn't know if they were better to use then PURE Gases but they cost much less.

Heli-Arc is suppose to be the HOTTEST as far as I know.

Ken. :)
One must remember.
The best learning experiences come
from working with the older Masters.
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steamin10
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Re: Mig welding aluminium

Post by steamin10 »

By acclamation I am overruled. I will check with my supplier on Monday. This may be one of those things I get dyslexic with over time. :evil: I hate being wrong, but I could be mistaken. :wink:

I have argon and steel mixed gas, no Helium.
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rustyh
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Re: Mig welding aluminium

Post by rustyh »

I finally got my Spool gun up and running this morning, with 100% Argon. I have the Miller Spoolmate 100, not the 200, on my Miller 211 with a 230v hook up.

Got a bunch of alu out of the box to play with, the first, a 3" x 36" square 16ga tube, absolutely filthy. Poured acetone on one side and scrubbed with paper towel, then wire brushed clean. Not expecting much, I set up as advised and laid down my first weld...wow, it started blobby for 1/4" then stacked dimes for 3" and when I quit, left a flat puddle. I repeated this over and over until the body got too hot. Sure do have to move when hot, but the welds then had more of a "vee" shape rather than fat dimes, I think that was around 12-3" welds, might have been more, as I did some on top of others, the last 2 had cracks across the end puddle, the tube was pretty hot by then.

Got different scrap out, 1/8" 6061 and cleaned, wire brushed, reset welder, and all hell broke loose. Spatter, weld smut all over, terrible messy flat puddle, plugged tip. Into the house for the book and laptop, then realized maybe there might be a bit of a breeze, so checked my weather station...um....12mph at the fence. Packed up and got ready for the rain on it's way in tonight (a Pineapple Express). I set up a small flag pole at the welding bench, the streamers were swirling around the pole floating up then slamming down, doing 360's....not good, I have the table in a rotor zone. A concrete slab is in the planning with roofed area and some siding, maybe by summer.

My one complaint is no matter how slow I depress the trigger, argon doesn't flow unless alu wire is extruding. I guess I have to not hook up the wire spool then press the trigger until gas has filled the hose. I wanted to take the pressure off the system when I finished, and it spit out about a foot of wire. Another observation was the initial bump to about 50cfpm of the flow ball when activating the trigger.

Back to watching youtube vids over again, they make more sense now.... :wink:
redneckalbertan
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Re: Mig welding aluminium

Post by redneckalbertan »

rustyh wrote:the last 2 had cracks across the end puddle, the tube was pretty hot by then.

My one complaint is no matter how slow I depress the trigger, argon doesn't flow unless alu wire is extruding.
Aluminum is very susceptible to crater cracking. When you finish your bead, pause for a couple seconds at the end of your weld and allow the crater at the end of your bead to fill up. If you are working on thin material, stop you bead when you get to the end, wait for the puddle to cool and then fill it up with a couple short pulls trigger.

Gas shielded welding processes don't like wind! Hoarding yourself in may help if you have to welding in a breeze.

That is strange. All the spool guns that I have used, have a half pull setting of the trigger which starts the gas flowing. Then the full pull starts the wire and current flowing.
rustyh
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Re: Mig welding aluminium

Post by rustyh »

Maybe it will work in, but I tried slowly pulling on the trigger and the flow ball would pop only when the wire shot out. I pulled down on the tension knob to release the wire feed and then watched the flow ball, not perfect but did work a bit....not ideal, good to get started though.

I have a pile of alu from sliding glass patio doors and use a flap wheel to strip away the anodizing, then hand wire brush once parts are set up and weld. Mixed results, any joints that I can get into a butt weld position are beautifully "stacked dimes", nice penetration.

BUT, any 90 degree welds are a mess. No consistency, so I haven't been able to specifically find the problem. I do find it hard to view the puddle when in this position and have had the wire heat up inside the tip and needed to quickly pull away to shoot out to cooler wire and save the tip (not fast enough to go through my stock of .030"). The nozzle in this position doesn't have any clearance if it's supposed to be 3/4" of an inch away from the joint. I have tried to position a 90 degree joint horizontal so the spray hits the intended area but the arc seems to flow back and forth to each side and then just drops globs onto the material with the tip melting on one side (usually tip melts away on side facing the vertical side of the joint).

Speaking of this, is it possible to make our own tips? Drilling the .030" hole would be my concern. The thread for the Spoolmate 100 it seems to be 5mm. Another thing, when I went through all my .030 tips I switched to .035's and had better luck, but it may have been I was more experienced and more cautious. Yesterday I found a supply of tips and some .035" wire and will experiment with that today.

So I guess what I'm asking is how do you guys do a weld in a 90 degree joint. I was expecting it would be easier because the gas would pool better, but it's been anything but.... :evil:
Carm
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Re: Mig welding aluminium

Post by Carm »

Not sure what you mean by "90degree joint" ?
But it isn't unusual to use larger tip size, especially w/a spool gun.
A little technique for the crater cracks...when you're near the end of the weld, whip out to the end and come back on your bead. The whip depends on a couple things but never should exceed your shielding.

You'll have to examine the switch in the trigger to see whether you can purge before feed. Switch either has two NO's or a timer back before the contactor.

Used to be a cleaner for aluminum welding, pink stuff. My memory (not trustworthy) says it is phosphoric acid. Works very well cleaning the weld zone.

There was also a grinding wheel, sort of a light tan color that had raised round dots all over, good for prep, vees and dressing, wouldn't load up. Alooneyum only. Didn't need the liquid prep with that, but not always practical.

HTH
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Harold_V
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Re: Mig welding aluminium

Post by Harold_V »

Keeping in mind, I am not a weldor, the topic of gas selection and how each responds. I recall that one gas provides a wider and less deep weld, while the other provides a deeper and less wide weld. I do not recall which one responds according to the description I suggested.

Assuming that comments in regards to width and depth are the case, would one still call one gas "hotter" than the other? Seems that isn't necessarily the case, but then I don't understand everything I should in regards to gas selection. I'd appreciate further comments in that regard.

Harold
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david5605
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Re: Mig welding aluminium

Post by david5605 »

Helium (or a helium/argon mix) gives a hotter weld. Here is one write up by ESAB.
http://www.esabna.com/us/en/education/b ... uminum.cfm

Are you welding down inside of the box or on the outside? I would think down inside the box you would really have to watch your gas flow more so than welding around the outside. Too much gas flow and you are going to suck outside air into the weld area. In any case I wouldn't go over 20 CFH when doing welds out in the open and would try down in the 10-15 range 'inside a box'.

I'd also do some reading up on different aluminums vs different fillers. Some weld for crap, others weld fine.

Also don't contaminate the aluminum by using steel brushes or brushes/grinding wheels you have used on other metals. Use dedicated stainless steel brushes for the aluminum.
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Harold_V
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Re: Mig welding aluminium

Post by Harold_V »

Thanks for the link. I now understand why one gas is considered "hotter" than the other. I had not considered the fact that one conducts heat better than the other.

Harold
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