[sgtnoah]

Hey fellas, I was wondering at what thickness you guys start to bevel aluminum butt welds? I looked for info on this and haven't had too much luck yet.

Thanks,
Pete

[450dualsport]

Good question, I have been wondering that myself. I have not been able to find much info on aluminum joint preparation either.

[noddybrian]

I would think personal preference & / or any applicable WPS determines this - some people like almost no bevel on quite thick material - but use varying gaps - for many especially with limited amps / duty cycle then a bevel helps - I like to bevel anything 1/8" & over as I just find it easier to control but takes more time to prepare - others with more experience & bigger amp machines will likely get away just using a gap - interesting question - I imagine there will be some varied replies - maybe some internet guru will find a site like the Miller one that has parameters including proper prep for varied joints.

[450dualsport]

From my reading it seems that you can weld a piece of 1" steel at 135 amps or so using 1/8 stick rods and just keep making passes until the gap an bevel have been filled, yet with aluminum everybody talks about using 300 amp + machines for welding anything over about 1/4". I understand about how aluminum sucks up heat and why that kind of power is needed. I also understand about duty cycle, but for the occasional small weld, could you weld a piece of 1/2" (or more) aluminum with a 220 amp machine by bevelling, leaving a gap and making multiple passes?

[Otto Nobedder]

Dualsport,

You have to consider that in AC TIG, only about 70% of the heat is actually going into the metal at a "balanced" setting. That's part of the need for so much power on aluminum. Also, the aluminum carries the heat away from the weld zone very rapidly, and you have to saturate a much larger amount of metal with heat to get a puddle.

That said, your example of 1/2" with a 220A machine is doable. A big preheat will reduce the time to establish a puddle, and the addition of helium to your argon, though not required, will help you move faster through a first pass, so you don't hit your duty-cycle before finishing. If you're at a 10% duty-cycle at 220A, you'll want to do an "interpass heat", so the metal is still hot as hell when your machine is ready for the next pass. Setting your arc control as far toward penetration as the cleanliness of the metal will allow will also help.

In other words, yes, a multipass weld can help a smaller machine do heavier work on aluminum.

Your mileage may vary...

Steve S

[Otto Nobedder]

As to the original question, I like a bevel on aluminum as thin as 1/8, but it's a personal preference there, to help my old eyes see what's going on more clearly. I've welded 1/4" in vertical with just a gap, no bevel, and got full penetration, but I'd think 1/4" would be about the limit with no bevel.

There's so much about this that's personal to one's style and experience, though, that I can't imagine a "hard and fast rule" governing it.

Steve S

[450dualsport]

Thank you for that explanation Steve, it helps a lot.

All of the aluminum I have welded (and will probably ever weld) has been under 1/4". It's nice to know that there are ways to make a smaller machine work if the need arises to weld some small bracket or part that is over 1/4". It's too bad that with TIG welders the incremental cost to get to the next level of machine is so high.

My apologies to sgtnoah if I have started to hijack this thread.....

[sgtnoah]

I appreciate all of your thoughts. I don't know how I'd learn TIG the right way without this forum and Jody's videos! I'm a single dad who works a lot of hours as well as raises my two daughters - taking college or vocational training is just not on the horizon right now. With all of your help and instruction, I'm able to sneak out to the garage after the kids go to bed, or on weekends that their mom has them and light up the welder a do some learning.

I'm not sure how to return the favor (other than ordering a bunch of stuff from Jody, as I have). All I can say is that I do advanced electrical and hydraulic troubleshooting in the farm equipment industry -- if you find yourselves in a situation that my skills could be of help to you, send me a note!

-- Pete

[Zerk]

Greetings all. Has anyone tried 100% helium? I have to weld some 1/2" aluminum plate together, and just read the tip from Jody about using different levels of helium. He mentions that 100% is hard to start an arc, but other than that any issues? I have a Thermal dynamics 185 amp AC/DC unit, so not as much power as usually needed. It is only decorative, so I'm thinking a bevel will help a lot. I also have a spoolgun for my 210 volt Hobart Mig machine, will that run on helium the same?

Thanks so much for your input.

Matt

[AKweldshop]

welcome two the Forum Zerk....
I would preheat it up "good" and Hot....
I would use the Mig on you 1/2 in material.
Anyone out there want to share any tips on spoolgun helium?
John