Justmakinitup
Plastic
- Joined
- May 7, 2006
- Location
- Longmont, CO
This is not so much a question as a little sharing of some how-to. I am pretty new to the board and was surfing some topics, noticed some posts last month on how to weld thick aluminum stock. A friend of mine at a local airgas just showed me how to do this for a project I am working on right now. Its a 6061 1" square bar framework skinned with 1/8 plate. I have a lincoln precision tig 275 and it couldn't touch it on ac.
Here is how he set me up. You need to use ultra pure helium for a shielding gas, use a 3/32 2% ceriated tungsten, can use thoriated too I just prefer the non-radiactive type. Grind a point on the tungsten just like you would for regular dc welding. Use a small cup, like a #4 to force the helium into a concentrated column with strong flow. Flow is about 20-25 on the regulator, but remember helium is so much lighter, at that flow rate you will empty a tank about 3 times faster than an argon/helium mix. The parts you weld haveto be REALLY clean, wire-wheel, scotch-brite, and maybe even an acetone wipedown, don't forget to clean your filler rod. Amps will be set at 200, was told that's about all you need for even the thickest stuff, was plenty for the 1". Then go ahead and start welding.
The weirdest thing about this process is that you can't see a puddle, the oxides all float on top of the aluminum and give the appearance of solidity. Hardest part is pushing the filler rod into the pool because you have to push past the oxide layer. Once its in there, I find it easiest to leave it right in the front edge of the puddle as I weld. Oh yeah, auto tint welding helmets won't turn dark when welding like this so you have to use an old school one.
With this type of setup I was able to weld the 1" solid frame without any kind of preheating. It was also fairly easy to weld the 1/8 skins to the much thicker 1" frame along the seams, something required for this job. Thought it would be tough not to burn the plate before the solid got good penetration, but with some torch control the heat distributes just how you want it.
Hope some of this is of interest to you guys, I have certainly enjoyed browsing some of the other topics
Here is how he set me up. You need to use ultra pure helium for a shielding gas, use a 3/32 2% ceriated tungsten, can use thoriated too I just prefer the non-radiactive type. Grind a point on the tungsten just like you would for regular dc welding. Use a small cup, like a #4 to force the helium into a concentrated column with strong flow. Flow is about 20-25 on the regulator, but remember helium is so much lighter, at that flow rate you will empty a tank about 3 times faster than an argon/helium mix. The parts you weld haveto be REALLY clean, wire-wheel, scotch-brite, and maybe even an acetone wipedown, don't forget to clean your filler rod. Amps will be set at 200, was told that's about all you need for even the thickest stuff, was plenty for the 1". Then go ahead and start welding.
The weirdest thing about this process is that you can't see a puddle, the oxides all float on top of the aluminum and give the appearance of solidity. Hardest part is pushing the filler rod into the pool because you have to push past the oxide layer. Once its in there, I find it easiest to leave it right in the front edge of the puddle as I weld. Oh yeah, auto tint welding helmets won't turn dark when welding like this so you have to use an old school one.
With this type of setup I was able to weld the 1" solid frame without any kind of preheating. It was also fairly easy to weld the 1/8 skins to the much thicker 1" frame along the seams, something required for this job. Thought it would be tough not to burn the plate before the solid got good penetration, but with some torch control the heat distributes just how you want it.
Hope some of this is of interest to you guys, I have certainly enjoyed browsing some of the other topics
