Welding Aluminum

[Alistair Hosie]

Anyone any ideas on welding aluminum, or braising, or soldering.
In fact any way of joining aluminum would be helpful.In may this year I bought my first mig welder it was one of the best buys I had ever made and while I'm no great shakes at welding I have found it to be a very handy tool.
Several years ago I purchased a whole bundle of rods from a guy at a giant fleamarket in florida Orlando it had a giant cartwheel as its emblem docsteve will probably know it.The guy cut holes in coca cola cans and filled tham as easy as pie with these rods.I have tried on numerous accasions to use them with absolutely no succes was I conned or anyone else bought them and managed to get them to work let me know where I'm going wrong.
Iknow you cant do aluminum with a mig or so I've been told any ideas .
Also been told its not an easy task to do in any case please give me some ideas as I would think this could be useful to me in the future regards to my friends Alistair

[RPease]

Alistair,

Those rods are really more like an aluminum "solder" that can be spread over an area or gap between two pieces of aluminum or to "fill in" a void. You have to clean the area to be filled with a stainless steel wire brush. This gets rid of all the "oxides" in the area. Then you heat the area (not the rod) until the area gets hot enough to melt the rod and then "paint or spread" the end of the rod over the area. Sort of like brazing or lead soldering. As far as I know, only a stainless brush will work and you can't wait too long before starting the soldering process or the aluminum will start to oxidize again and it won't take the solder. As you "spead" the solder over the area, it pretty much sticks to itself and forms a fillet across the area. Doesn't really "weld". You also need a "clean" flame, like propane. Can't have any "soot" or carbon black or it will contaminate the surface that you are trying to solder.

As you say, you can get that stuff at many flea markets. I think Harbor Freight also sells the stuff.

Regards,

Rodger

[HOTRODCHEVY]

I have yet to try welding with those rods that you talk about,but if you have a decent sized mig machine you can weld aluminum with it.You also have to run helium gas with it to produce a strong,high quality weld. I am a welder by trade and weld stainless, carbon steel, and aluminum all day long with a tig machine.Tig is the best way you can weld aluminum because it produces a far better weld. If

<font face="Verdana, Arial" size="2">Originally posted by Alistair Hosie:
Anyone any ideas on welding aluminum, or braising, or soldering.
In fact any way of joining aluminum would be helpful.In may this year I bought my first mig welder it was one of the best buys I had ever made and while I'm no great shakes at welding I have found it to be a very handy tool.
Several years ago I purchased a whole bundle of rods from a guy at a giant fleamarket in florida Orlando it had a giant cartwheel as its emblem docsteve will probably know it.The guy cut holes in coca cola cans and filled tham as easy as pie with these rods.I have tried on numerous accasions to use them with absolutely no succes was I conned or anyone else bought them and managed to get them to work let me know where I'm going wrong.
Iknow you cant do aluminum with a mig or so I've been told any ideas .
Also been told its not an easy task to do in any case please give me some ideas as I would think this could be useful to me in the future regards to my friends Alistair</font>

[Thrud]

Alistair
You may be able to weld Aluminum with your MIG. Usually it requires replacing the gun/cable liner with one made of teflon and the addition of an Argon flow regulator. A 200A minimum rated welder should be used, but you may be able to get away with less current by attaching the ground clamp directlyto the workpiece.

You should be warned that MIG welded Aluminum is not pretty, and you get lots of carbon scoring to clean up. TIG or Gas welding works best.

[Eutecticbob]

Alistair,

Specifics would be good... I could tell you how many feet.. probably miles I have welded of aluminum... aircraft and missle certified tig welder.

Gernally speaking... the cleaner the welding process the better you will be... THE BIGGEST KEY TO WELDING NON FEROUS METAL... is...

METAL PREPARATION!!

Aluminum is really sensitive to dirt and grime (this is why I had to weld so much aluminum to pass x-ray tests).

It can be done with mig... and you can get it nice... but it is going to be an extensive project to do it... you can be spools of aluminum wire for mig and I would suggest that you keep extra mig consumable around so that you can replace them as you learn how to finess the metal. You should also consider going to the traditional... helium gas cover... I don't understand the science behind it but for what ever reason helium allows you to burn hotter and that is a key to doing this.... Also remember that aluminum has great heat sinking ability and as Thrud said... you will want to burn HOT!! If the piece is relatively large or massive.. pre-heat the peace.... hmmm what else is there?... Go AC if you use TIG... ball the end of your electrode by jumping a spark to the ground with the welder on positive setting... the positive setting put more heat on the electrode and less on the parent metal...

hmmm mig... hmmm do make sure your nozzles are clean... turbulent cover gas can be very irritating to deal with... especially when you are learning...you don't know if it is your welding technique... or poor coverage... by the way... if you think AL is touchy about cover gas... try titanium!! GRRRR Hydrogen embritlement (for go the spelling please) is Titaniums' worst enemy.

The only other thing I can think of is the aluminum... 2000 and 6000 series are best for welding and whatever you do.... DON'T EVER CONFUSE magnesium rod for aluminum rod... it is a really cool way to destroy a welded part!!!

I have been running on enough... let me know if there is anything else I can tell you that I have forgotten.

EBOb

[Dr. Rob]

Only that MIG-ing alu requires polarity reversal of the ground clamp / squirt gun. Or so I've been led to believe.
The rods sold at fairs are something of a mystery. (Of course I bought them too) but learned that not only do they require a clean flame, but one of a certain shape as well, known as a cyclone burner. (kind of a vortex shape)
However, more established soldering methods are available from AGA. The stuff is poisonous (cadmium) and works excellently. The key here is not only preparation, but PRACTICE. With time, excellent results can be achieved. This is a hard solder, melting in the high 400*C range.
Also available are electrodes for stick welders. Very sensitive. I have never been able to do this.

[This message has been edited by Dr. Rob (edited 12-15-2002).]

[KACHINKOO]

Alistair, Alum. can be welded with mig easily with a spool gun. Talk to your local supplier, he's the best one to pick on with these questions. I've been welding alum. for years with my tig, when we get a job in with a LOT of alum to do, I rent a mig with a spool gun. Different kind of welding for sure, and you need practice as with anything. For all the yacht welding,tig is the only way to go because appearence is key, however, for work boats, mig is not as pretty but comparativly is VERY fast. The fishermen love that. Alum. is not hard to weld, it is finickey tho. Cleanlyness is next to Godlyness and joint prep is critical. Practice good luck Dave

[docsteve66]

Alistair- buddy, especting that I might know a florida flea market is like me expecting you to know a beautiful blue eyed gal with pretty legs over there.

Flea markets are every where in florida. I rather come look at your pretty blueeyes gals ! &gt;
Steve

[Thrud]

Alistair

You are better off looking for a used AC/DC reverse/straight polarity TIG at one of those sales. That and 600A will allow you to weld anything you could dream up. It would cover all your welding needs that way. Or go dowm to a welding distriputor and see what they have.

If I was going to buy a new unit I would get one that can handle stick, GTAW, GMAW, and Plama arc cutting, AC/DC Straight/reverse polarity, High frequncy start. Gas flow regulators.

BTW - Argon works best for Aluminum because it boes keep the arc hotter. Argon is enert and a very poor thermal conductor - the reason they pump it into low emissivity windows. It also happens to be cheaper (here) than Helium.

SAFETY NOTE: The one problem with Argon is because its atomic weight is high, it gathers in low places and can fill your lungs and kill you of you are not careful. USE IN WELL VENTILATED AREAS!

[This message has been edited by Thrud (edited 12-15-2002).]

[Paul H]

I've used mostly TIG, but also MIG for aluminum. I greatly prefer TIG.

Someone mentioned needing a new liner for your gun, this is true, and in addition, you should get a new set of rollers for the feeder. The small amounts of copper that has worn off your steel filler wire is just enough to contaminate your welds, which is why you need a new liner and wheels.

One thing to consider when welding say 6061-T6, the weld zone looses the T-6 condition, and annealed 6061 is ~1/5 the strength of the T-6 condition, as I recall. Heat treating tends to warp aluminum weldments as well.

Clean, clean and cleaner when welding aluminum. Nice thing about TIG is you can use the plasma to provide a bit more cleaning in the weld zone before you create the puddle. And since al. conducts heat so well, the metal is really hot at suprising distances from the weld zone, so you'll learn those welding cuss words all over again from grabbing hot metal.