6061 Aluminum.... Question?

[CGCINC]

A guy is bringing over a machined part made out of 6061 Aluminum that he needs a 3/8" hole welded in, it was drilled in the wrong place. The part is 3/8" thick as well.
I'm wondering if all 6061 is extruded and is there any special settings for my 250EX to weld it?
It also has been bathed in oil during the milling process

[Rodsmachineshop]

can use 4043 or 5356 .. 5356 will match color better that 4043 http://www.esabna.com/us/en/educatio...ng-6061-T6.cfm

[CGCINC]

Color matching isn't a problem. I'm using 4043 But I'm wondering if my "regular" Aluminum settings on the 250ex will work for 6061 or do I need to change anything?... Freq., balance?

[sportbike]

5356 will have higher strength on 6000 series product of that thickness.
Not all 6061 is extruded, it is likely rolled plate if it is a fully machined part.
No matter what you do, the welded part will not have anywhere near the strength of the base metal (neither yield nor ultimate tensile). You could have the part post weld heat treated and quenched, but it is quite expensive and has a relatively high distortion risk.
You may want to inquire about chamfering the hole prior to welding as it may be difficult to get complete penetration with a cylindrical hole that is that small.
You can use a copper backer if you wish to lessen the backside dropout.

[Rodsmachineshop]

no just weld same -on a small hole like that i bevel on both sides so can get to center and work my way out of hole and have good penetration and works like a plug

[Rambozo]

A little acetone will clean up the oil. If the hole is threaded, I would drill out the threads as they tend to hold contaminates. Chamfer for better access, or even drill the hole larger. Copper on the back will support the weld metal and trap some argon, but it's not really necessary for that size and thickness. Since you have access from both sides, you can weld from both sides.

[srp]

I use 5356 to weld 6061 to 6063, 4043 does not weld all that good to me on 6061. I have repeatedly tried 4043 on both the Syncrowave 250 and the 250 EX, never being completely satisfied with the finished weld. The only thing in common between the two welders is the coolant is distilled water. Miller does say the water should be deionized water, Miller also says the high frequency can bleed into the arc if deionized water is not used, this may or may not be why 4043 does not weld very good for me.

[CGCINC]

Well, I got it welded.
Cleaned it with Acetone and it looked nice n shiney but once I started welding you could smell the oil burning.... I'm guessing the metal soaked up some oil in the milling process. The part is for a small robotic arm.

[srp]

Well, I got it welded.
Cleaned it with Acetone and it looked nice n shiney but once I started welding you could smell the oil burning.... I'm guessing the metal soaked up some oil in the milling process. The part is for a small robotic arm.

That milling machine coolant really stinks don't it? I hand wash all of my machined parts with soap and hot water before welding.

[CGCINC]

That milling machine coolant really stinks don't it? I hand wash all of my machined parts with soap and hot water before welding.

Huh, soap n water... Never thought of that!! I figured Acetone would do it but Man did it stink!

[Rambozo]

Huh, soap n water... Never thought of that!! I figured Acetone would do it but Man did it stink!

It all depends on what kind of coolant. If it's oil based use acetone, if it's water based use soap and water. When in doubt use both. Was that hole threaded? Threads will hold stuff, so it's best to drill them out. It also looks like that might even be a casting. Those are known for holding fluids.

[Winky]

"Well, I got it welded"

Nice job ... I've just started welding aluminum myself ... compared to steel it's quite challenging.