TIG welding thin (.030) AL

[TWA]

I'm trying to butt weld .030 aluminum flat sheets with my Square wave 180. I have no problems running a bead on the flat material but as soon as I try to weld 2 pieces edge to edge, i'm melting the material before the rod even with the amp set at 7, the machine's lowest setting. I'm using 1/16" rod, and 1/16" pure tung. the flat plate is 2024-T3 (I know 6061-T6 is better)is new but I've brushed it with a SS brush and cleaned with acetone. I've even tried cutting a sliver of the aluminum off to use as a welding rod. My cup is 7/16" which I think is a bit large but would it make that much difference ?

Is there a trick to welding this thin stuff ?

Thanks for any advise

[Paul Seaman]

I've seen .005 303Al and they used a circular pattern with no filler added. The fitup had to be perfect. He did it with a dynasty 300dx and set at 3 amps,I'm not sure the % balance, but he was moving really quick with a whip across the center and a slight hesitation then back. The man doing the work was awesome!

Hope this helps,

[paulrbrown]

TWA, can you do a lap weld instead of butt??? I have also heard of taking your TIG lead and wrapping it around a steel pipe for a few turns, [don't know for sure how many] to reduce the amperage even more, as this makes for some sort of resistance. It also may help to have a piece of copper or even thick aluminum behind to act as a heatsink. Hope this helps, Paul

[TWA]

Thanks for the replies.....

Paul,

The piece I'm trying to fabricate is an oil cooler baffle (my design) for an experimental aircraft, so I have plenty of latitude. The baffle on my plane is the same design but riveted; and since I now own a Syncrowave 180 I was hoping to really make this and other products really slick by welding them. So the answer is yes it can be butt welded. However, I doubt I can keep the edges from prematurely melting. I will remember your ideas, however I have never heard about adding resistance to lower resistance(but since I'm fairly new to the TIG process that's not surprising.

It seems to me that if I could develop a softer arc, maybe I could control the heat better. Would a different electrode help ?

I am hoping to hear from someone who has first-hand experience with TIG welding thin AL especially 2420. FYI... I have edge welded .049" X 6061-T6 1" tubing...very carefully !!

Tom Warren

[paulrbrown]

TWA, by making a bigger ball on the electrode, it will spread out the heat instead of focusing, this may also help, Maybe HAWK, the Forum Guru on TIG may also have some Ideas...and when you refer to butt welding, do you mean at right angles or edge to edge? Paul

[HAWK]

TWA,

You can also reverse the polarity to DCRP to concentrate the heat on your tungsten rather than your work. Just a thought.

[fun4now]

exaple

wheels posted this a wile back it might be of some help to see his work.

The Dreaded Outside Corner
1/16 Aluminum of unknown alloy.
No filler
70 Amps

Attachment: 2004_0628image0002.jpg
This has been downloaded 221 time(s).

that was a coppy and paste so ill atachhis pic.

[fun4now]

pic

sorry i forgot to atach. . here is wheels pic of outside corner.

[TWA]

James and the group,

Wheels' picture depicts exactly what I'm trying to do at this time. However my practice work is strickly flat butt-welding...edge to edge. I have not tried some of the suggestions i.e. heat sink, bigger ball on the tungston, and DCRP. I also need to read Wheels post, which I've not done yet but it sounds like I'm on the right path.

Thanks for all the help.
Tom Warren

[glockdoc]

I have had some luck using DCEP on thin AL stuff. It gives you 100% cleaning but you need to watch the limits on your tungsten and torch as most of the heat is concentrated at that end. When using AC welding current I usually end up cranking the balance all the way over to max cleaning. Is 2000 series AL weldable? Would 3000 series be a better choice for your application? Wrapping the cord around a piece of steel creates an inductance in the welding circuit (I think).

[Sberry]

Can you fit the peces like this,,, makes a big difference.

[TWA]

I've got it !!!

I've now been able to butt weld 2024T3 AL. It ain't all that pretty yet but it's to the point where it's practice practice and more practice.

For future reference here are the particulars;
I set my Syncrowave 180 digital input for a "Soft Start"- setting(1).
1/16" AL rod 5356
1/16" Pure Tungsten electrode (green)
3/8" cup
18lbs CFH scale....100% Argon
Balance (penetration): 8
AC (20amps)
Clean material with SS brushing and Acteone
Material butting - no air gaps.
-------------------------------------------

Prepared the Tungsten normally,as follows;
Square off the end of Tungsten
Set TIG to DCEP and 70 amps
Align tungsten vertically over 1/8" (or thicker)flat copper plate
Initiate an arc to create the proper sized ball.
.................................................. .........

Well that's it for now. I feel confident that with more practice I will be able to produce acceptable welds.

Boy this TIG process is really great with all the variables we can dial-in to the overcome a problem.
Thanks to all who helped with suggestions. And if anyone has more to add, I'm all ears. However I will not be available with a reply for a few days as I'll be out of town.

Talk to you all later and thanks again,

Tom Warren

[HAWK]

Originally posted by Sberry
Can you fit the peces like this,,, makes a big difference.

Good diagram. That's how I got the .004" hastealloy to fuse.

[FM117]

Hi all
I've had good luck on thin materials
by using .020 mig wire instead of
tig rods. It makes it much easier to
get the filler to melt along with the thin base material.
Dave P.

[ASKANDY]

Good point Dave and welcome!

As long as it has an ER rating on the wire it can be used for TIG.

A-