Welding aluminum?

Guys,

I had to make the mounting pieces for the steering column in my Sabre. The pieces go into a 1x2" piece of box tubing that spans the to front center of the structure for the front of the driver's compartment.

Fabricating this piece was a pain because it involved milling a 1 1/2" hole into split aluminum bars at an angle. The piece came out perfect as to angle and fit to the column.

Unfortunately, the column is now 1/4" to far to one side as the hole should not have been in the center of the hole for the mount ... as I assumed that it would need to be. This causes the dash to be off center which would cause the spyder to be off center in the front.

So ... I either remake the piece, or weld up the holes and one side of the ledges and recut them so that the mount is properly off center.

Has anyone done any MIG welding on 6061? Is this approach worth trying?

Thanks!

Mike

I don't believe you can MIG/TIG weld aluminum. It must be Heliarc welded. I will try and talk to our resident welding gurus here at Boeing and see what they say. How thick is the aluminum?

Bill D

6061 for fabrication is usually in a hardened condition. It should be marked 6061-T6 (or T4), the T6 indicating the level of heat treat hardness.

Welding anneals the material bring it back to a dead soft condition in the HAZ of the weld. So in effect 6061-T6 becomes 6061-O .

Tensile strength - KSI of 6061

6061-O max 22ksi
6061-T6 min 42ksi

So after you weld the weld area is half as strong, unless you have it re- heat treated, which causes warpage unless the piece is jigged.

In addition MIG aluminum welding is problematic in that the start of the weld is always cold. So you have to either finish through your start, or start before the spot where pieces are actually joined. TIG overcomes this.

Might be easier to just fabricate another piece with the hole in the correct place, unless strength of the piece is not an issue.

I have a box of JUNK parts that I keep to remind myself of all those holes drilled in the wrong spot, it gets bigger over the years and it's been 4 so far.

Recently building a front brake cooling air duct, had it all laid out and it looked really nice until it was noted that the duct went all the way from the entrance to the brake with no provision/joint for opening the front body section.... dohhhh!

Not a guru, but good at faking it.

MIG, Metal Inert Gas, uses a consumable electrode (the wire feed), you can weld aluminum, common in the boat and semi trailer industries. Faster than TIG but not as controllable.

TIG, Tungsten Inert Gas, non consumable tungsten electrode, usually done with a separate filler welding rod (hand held). A lot more controllable and usually provides better welds especially where a lot of stop and start is necessary.

TIG is commonly called Heliarc because the first TIG welders used Helium as the shielding gas, (they now use argon as well as helium) and it was the companies trade name for the welder.

The helium added for tig welding, is to help float the impurities out of the molten weld. If you preheat the aluminum pieces, it helps with penetration, and the strength of the weld, especially when mig welding. I really don't think that if you have a good quality weld with the mig welder, that the loss of the heat treat is going to give you a un-useable part. There isn't a lot of stress involved in hanging the column. However if it were me, it would be in the scrap, and I would be making a new one. I hate knowing that I have those kind of parts in my car. Even if it is out of site, and not a safety issue, I just start over and make new. Just my point of view !!!

Regards Brian

MIke
This is right up my alley!
WE mig weld aluminum all day using a Spool Gun setup..the essentially a handpiece with the spool on the back, the aluminum wire feeds only about 1 1/2" thru a straight run to the tip, this is the only real way to mig weld aluminum as the standard cable/wand assembly has far too much friction in the run (usually 10 to 12 feet depending on the model) and you constantly get a "birds nest" at the feed rollers, this is a production setup and I usually don't try to weld anything less than 1/4" thick as it is a high penetration setup and will melt thru. Also keep in mind that MIG is a constant voltage output, and current can vary greatly depending on line voltage etc.
The TIG process we use is for the thin stuff, I regularly make parts out of 16 ga. and thinner and have no
problems whatsoever, keep in mind that a good tig machine will run you some serious dollars, and the associated parts and consumables associated with the torch etc. can get pricey.....we use different electrodes for DC and AC, and different sizes for the current values, this means internal parts in the torch must be changed to accomodate the thinner/thicker electrodes. Also I use a water cooled torch on most jobs rated at 300 amps, this sounds high but if you have ever worked a while with a gas cooled torch you will understand that you really need that cooling. When you tig weld you will need some serious current at first, as the part heats up you will find that less and less is needed, as much as 1/3 the current less. The TIG process is constant current, and very controllable with a foot pedal which you really need for that thin stuff.
If you decide to weld that part I would say it would hold fine, If you need any additional info just ask.
Good Luck
Phil