Aluminum Welding Help
 

I'm fairly new to TIG so I have run into an issue that might have a simple answer...but I'm stumped and I know there are some great welders here... so here goes. I am building a sheet metal brake for another project I thought I would make out of Aluminium I had laying around. I am attempting to attach the legs I made to the main base. I can't seem to join the two and was hoping someone could explain what is going on.

So here is the backstory The main base is 1/4in 6061 and the "legs" are 1/16in aluminum scrap(so I do not know exactly what it is). I thought if I could focus the arc on the thick metal , heat it knowing I am not going to get fantastic penetration, and just melt the thinner metal into the base I could join the two without blowing out the thinner metal. When I strike the arc the tungsten immediately eats away like it would if you struck it without and gas. I tried two different tungstens and both did the same thing. I cleaned the first time with non-chlorinated brake cleaner. I thought it might be something to do with surface prep so I scrubbed with a wire brush and then wiped it down again but no change. I then ran a bead on a scrap piece of aluminium I practiced on previously to check to see if the welder was malfunctioning and that bead was fine. Here is the list of specs and settings I am using:

Eastwood TIG 200 set to AC
3/32 grey tungsten
100% Argon is set at 20
foot pedal at 140amp
Clearance Effect set at -1 and then +1, no difference
#5 alumina cup
pre flow is .5 sec

Here is a shot of the tungsten that is thrashed. This happened immediately as the arc was struck. At least a few mm were lost as the tungsten just kind of dissolved before my eyes.
http://i1080.photobucket.com/albums/...pscd1780cf.jpg

Here is the work Piece. On the left I got a little bead happening the first try but the tungsten was trashed and I was just trying to glue the pieces together.. I was forcing it. The right is the last attempt where you see the buildup of filler. As soon as the tungsten went the arc looked like a giant cone and immediately melted the thinner aluminium so I tried to get filler in to plug the hole. Ugly and wrong..I know.
http://i1080.photobucket.com/albums/...ps21fb92f5.jpg

I pulled out a practice piece and ran a bead that you will see circled in red. No settings were changed, same type tungsten but a different one since the original two were beyond use, didn't even adjust the pedal just feathered it. Tungsten was fine.
http://i1080.photobucket.com/albums/...ps259e262c.jpg

I have accidentally struck an arc without the gas on before and what happened to the tungsten then was exactly what I saw here but the gas was on. I know it has something to do with the work-piece since the welder was fine on the scrap.

Is this somehow because of the thick base plate I was working with? Also, I am a definite newbie to TIG so any comments on the bead on the scrap is welcome, my travel speed was all over the place I know :(

you should be fine after 100 feet of practice.

I have found you get better welds if you use the cleaning action of the machine. I no longer brush clean. Just wipe down with acetone.

Practice.

Maybe Greg will chime in on the heat and thickness. Also your choice of tungsten. Type and size for metal thickness?

+1 on 100' of practice, it took me at least that and 150 cf of gas to get close to comfortable.

From my experience TIG has next to zero tolerance for contamination and if you touch the tungsten or it gets splattered don't even try to continue, stop and regrind the tungsten.

Use Miller's phone app weld settings for a handy baseline amperage reference.

this video was a ton of help for a while back. Came out with cleaner welds.

My problem I was trying to force the filler. Mainly due to poor heat control.

I definately do need another 100ft. I try to weld 10 or 15 minutes a day at least to practice. I'm pretty busy but I try to get at least some time in each day. I'm actually feeling more comfortable quicker with the aluminium than when I was focusing on steel. For some reason I feel I see the puddle easier once it forms. Everyone can carve 10 minutes out right? I'm really just stumped why the tungsten was eating itself yesterday.

Vince and Sieg, thanks for the replies. I can't see the video, I don't think the link posted Vince.

Link's working for me this morning.........?

I too experienced the feeling that aluminum is "easier" than steel. Visibility definitely plays a role and the it appears on average to be cleaner than steel.

Regarding the tungsten.....are you set to AC? Hold-off distance?

heres the link to it....

https://www.youtube.com/watch?v=ZWJt3...mQrp2uSysIeVUQ

oh, almost forgot, gas lense was the other thing I added. Good consistancy, visability and increased tungsten stick out makes welding easier.

Weird, there isn't even a link to click for me. Guess I'm not cool enough:)

The machine is on AC. Hold off distance is short. Basically as close as I can without fouling the tungsten...which has happened more than I care to admit though. I have seen a lot of stuff that said the arc length was a factor in heat input. Shorter at length at a given amperage will result in less distortion than a longer arc length at that same amperage so I generally have the piece up on something so I can rest my hand on the table and just drag my hand o try and keep it consistent.

Thanks for weighing in. I followed your TIG journey here and you definately got it down now!

Edit* posted this before seeing that Vince reposted. I see the link.

I certainly don't have it down but my level of frustration has decreased!

FWIW - I'm typically running 16-17 cfh with a gas lens.

Keep it up and you'll be laying these down.......

https://scontent-b-pao.xx.fbcdn.net/...80227909_n.jpg

https://scontent-b-pao.xx.fbcdn.net/...82547130_n.jpg

Maybe.......:D

You need to check your A/C BALANCE settings.... just A/C is only one setting -- now you have to balance the A/C for cleaning vs heat input... when cleaning the heat is coming back to the tungsten (A/C being oscillating). If the balance is set wrong you'll eat your tungsten.


Set your balance around 70% EP (electrode positive) ---- and your frequency around 100hz or greater.


Not all aluminum alloys are weldable.