TIG Welding Aluminum

[Paul F]

I'm looking for some help on aluminum TIG welding. I've searched the web but not found what I'm looking for. I don't seem to be able to consistently get a nice clear puddle. In fact, I rarely do. Most times, the aluminum has a slag look to it when I heat it up rather than a nice clear liquid puddle. I figure I'm not cleaning it right. I've played with the gas flow, frequency, to no avail.
Can anybody tell me what I'm doing wrong or point me to a site?

I'm using a Miller Dynasty 200.

[133bus]

Paul
Sounds like a contamination problem.If the brush has cleaned any steel it will transfer to your aluminum.What does your end product look like?
Steve

[mickmate]

Sounds like you need to overbalance it (you should have a control for that) to clean the weld. Make sure you use a stainless wire brush to mechanically clean it and only use that brush on stainless. There are some good tech articles on the miller web site here.http://www.millerwelds.com/education...les_search.php

[mickmate]

Found the one I was looking for, I printed this out and keep it on the machine
http://www.millerwelds.com/education...rticles15.html

[cab]

are you set to the a/c ,and set the balancne to 65 -75 ,I run my gas at about 20 and run argon alium must be clean and deburr the apart.

[Paul F]

Thanks guys. I'm going to try a new SS brush.

Weld looks like this. I can't get a better picture. Camera doesn't have a macro.

[LMH]

I haven't used a TIG welder in 20 + years, (which is when I was taking classes in welding) but I remember taking the electrode out and grinding a point on it. Then I would strike an arc with it and form a ball on the end and let it cool. Then proceed to the aluminum for the weld.
Not sure if anyone else does that and it has been a long time but that's the way I was taught. Made it fairly easy to control the puddle.
Larry

[cab]

keep the rod off the tugsin if not the rod will build up and will look black dirty ,I have the same mechine as you do ,I use the small torch if you have the big one that came with it keep the angle more uprite to keep the gas in weld area ,when starting move in realy small circals over where you are going to weld use a 3/32 tugstin when it gets shiney dip the rod ,I do this every day

[Aussie Mike]

Don't grind the electrode for aluminium. Just put it in straight out of the packet. It will melt itself into a rounded end if it's all set up right. You should also be using a straight tungsten electrode (Grey or white painted end from memory). The Zirconated (spelling?) electrodes with the red painted end are for steel and shouldn't be used on ally.

When welding steel or stainless grind the tip to a sharp point tapering over about 1/2" Make sure you grind in line with the electrode rather than side on as it effects the shape of the flame. You should also wear a respirator when grinding electodes as some of them are mildly radioactive.

Wire brush the work piece just before welding and you might also want to look at your clean width setting on your welder. I've only just recently started getting good results on aluminium and all I can say is practice and more practice.

There's also a formula for tip size vs welding current vs nozel size. Most of the time I use a #6 nozel with a 2.3mm electrode (from memory. I'll check tonight)

Cheers

[mickmate]

You are in AC right? Give it an amp per thou. If you're welding .090" use 90 amps. Here's the deal, you have to get right in there and after it. Heat both pieces to be joined until they are starting to melt and dip the rod between them to drop a blob of ally in there. It is a bit of a head trip just getting going with the magnesium trying to burn and all. If you just kind of commit to blazing those pieces together you'll get it.

[Paul F]

Thanks Mike, yep, I'm using straight tungsten. I may have the gas flow up to high. I'm going to cut it down and also get a new SS brush.

Mickmate - Yes, I'm using AC. The amp/thou is a good tip.

I'll try it again with everyone's tips in a few days.