First aluminum welds

[BB69]

I finally got some pics of my first aluminum welds. These welds were made in the TIG welding class I am taking. They are from the first day of welding. We started welding 1/8" thick aluminum coupons together with a simple butt weld. The instructor had us position the coupons so there was about a 3/32" gap between them we had to fill. I was amazed at how much filler is needed for this. I am struggling to get enough filler put into the weld. As a result, I am not getting as much build up on the top of the weld as I want. However, I got enough build up, along with full penetration for the instructor to have me move onto lap welds. That's where I will pick back up this weekend.

Caution, these pics are large so you can see the detail.

Lap weld
http://home.comcast.net/~grulich69/w...D-2625925.html



Butt weld
http://home.comcast.net/~grulich69/w...D-2625921.html

I have a lot of practice time ahead, but I am enjoying it.

Ken

EDIT: I finally figured out how to add thumbnails. These are much smaller than the pics in the links.

[Matt@RFR]

See attached picture.

What I've circled is REALLY REALLY bad. It's either cold lapping or the material/puddle rejecting filler metal. Either way, there's no fusion there, and it's just begging to tear.

Remember, the heat goes where you point the tungsten. Lap welds suck on aluminum, but you HAVE to get heat into the base piece.

[BB69]

Thanks for the advice Matt. Those were some of the same areas the instructor pointed out. Like I said, I haven't passed this objective yet. I only had a little bit of time to work on lap welds. I will get started back on those first thing tomorrow morning. The hardest part for me so far is being able to feed in the filler without stopping to regrip it. Any suggestions for that? I have seen people that advance it with their thumb and finger, but I haven't been able to do that yet.

Ken

[Matt@RFR]

It really sounds like you need to use much bigger filler. You should be able to a 6" weld without repositioning the filler in your hand no problem.

On an 1/8" lap, I would expect to use 3/32" filler.

[BB69]

I was using 3/32 filler for everything. I had the output set at 140 amps, and the AC balance set slightly more to the penetration side. I was also using a 3/32 tungsten as well. I was getting good penetration, and the width of the weld seemed good, but I could only go about 2" on the butt weld and about 3" on the lap. I held the filler rod so that there was maybe 8" exposed. The instructor held the filler rod much further back. I tried that, but I didn't feel like I had enough control over it. That will probably take more practice.

Ken

[Matt@RFR]

Is there any helium in the gas you're using, by any chance?

[BB69]

Matt,
I will ask tomorrow. We run off a header system, so there wasn't a bottle to read. I thought we were using pure argon, but I will find out. The instructor sure didn't have any problems laying down a good bead, so I think it might have something to do with me. What were you thinking though?

Ken

[Matt@RFR]

My thinking was that with 3/32 filler, you shouldn't be having any problems getting the puddle to fill up, especially with how close together you're adding filler. And your max amperage (140) is alittle hot, but not too bad.

Helium mixes burn hotter at the same amperage as pure argon.

I'm willing to bet, assuming pure argon, that the main thing you need to work on is arc length. You should be able to see the reflection of the tungsten in the puddle when your arc length is short enough.

[myclone]

My thinking was that with 3/32 filler, you shouldn't be having any problems getting the puddle to fill up, especially with how close together you're adding filler. And your max amperage (140) is alittle hot, but not too bad.

Helium mixes burn hotter at the same amperage as pure argon.

I'm willing to bet, assuming pure argon, that the main thing you need to work on is arc length. You should be able to see the reflection of the tungsten in the puddle when your arc length is short enough.

Good info Matt. As always I learned something from your posts and if no one has said it already "thanks" for chiming in with excellent help for us noobs at welding.

[Matt@RFR]

.

[BB69]

Thanks again Matt. I am eating breakfast now, getting ready to head to class. I will take your advice and see what I can do. What number shield do you use in your helmet when working with AL? Do you change it depending on TIG or MIG, or even material?

Ken

[Matt@RFR]

This is one area that I can't help in. There's too many options (blue, green, gold, black, plastic, glass, and shades from 8-14), and your eyes are garunteed to be different than mine.

Most guys can't use the shades I use. I use a black 9 for everything from .083" tube to 3/8" plate. I switch to a black 8 for anything thinner, and go to a black 10 for anything thicker. The most I've ever used was a black 12 when welding 1" plate at something like 375 amps with 1/32" dual shield.

If you want to try the black filters, I think I still have the part numbers for each shade in glass....it took me like 3 months to find them, but they're the only thing that really works for me. And I tried literally every other style.

Basically, keep trying different colors until you can see clearly, and the colors you see make the most sense to your eye, and then use the lightest shade you can without any after affects (blue dots). Then go one shade darker.

[BB69]

Matt, thanks for the advice. I feel like I can see the puddle pretty well with no affects on my eyes afterwards. I may see what they have at class to experiment with.

Here are the welds from today. I passed my lap weld and tee joint. I felt much more comfortable today. I realized that last week I had the torch too vertical. Today I angled it slightly so that is was pointed in the direction of travel, and that helped. I also stepped up to a larger filler rod on the instructor's advice. It requires more care to keep the tungsten out of the puddle with the larger rod, but I like it. For the tee joint, I extended the tungsten out of the cup more. That also worked well. By the way, we are using pure argon.

The pics are of one of my lap welds, and a couple of the good tees.

Thanks again for all the advice.

Ken

[Matt@RFR]

That last fillet looks good. You're doing great.

[BB69]

Thanks Matt. It's fun when you are doing well. I must have made 30-40 welds today. The only thing I don't agree with the instructor on right now is that he tacks the pieces before cleaning them. We are working with pretty clean coupons, but I noticed a difference when I cleaned the coupons before tacking. Then, I clean the joint again after tacking. Doing some different things I did today, it was obvious that clean metal has a large impact on the quality of the weld. More to come next week.

Ken

[Matt@RFR]

Yeah, you're exactly right. Cleanliness is everything in aluminum welding. Keep on doing what you're doing, and if the instructor has a problem with it, please refer him to me.

Also, remember that aluminum forms it's own protective layer of oxides when exposed to atmoshpere, so you really only have a window of a couple hours between cleaning and welding. This goes for your filler too. Big shops that do critical aluminum welds (think aerospace) will store their filler and weldment part is a pure argon chamber if they will not be used within 2 hours. For us mere mortals, that obviously isn't necessary, but I never let a cleaned aluminum part sit before welding for more than one work day, and never overnight.

One trick you can use is to start an arc, but not a puddle, and run the arc over the weld zone and let the AC+ clean the material for you. This only works on parts that just need a touchup to be clean enough.

[SShep71]

Ken,
I know matt pretty much explained eveything you need to know. I just have 2 suggestions, I dont know what your using to clean the AL but I use scotchbrite pads, tear off a small piece and use it lightly. Try cleaning your filler with alcohol, and snip off the first 1/4 of the filler rod. Sometimes dirt can become embedded in the end of the rod.

[BB69]

Ken,
I know matt pretty much explained eveything you need to know. I just have 2 suggestions, I dont know what your using to clean the AL but I use scotchbrite pads, tear off a small piece and use it lightly. Try cleaning your filler with alcohol, and snip off the first 1/4 of the filler rod. Sometimes dirt can become embedded in the end of the rod.

Thanks for the tips. We use a stainless brush. The filler rods are just stored in a tube next to the welding stations. I don't know what they would allow for bringing in any alcohol, but I will talk about this with the instructor.

Ken

[SShep71]

I wouldnt recomend a stainless brush, It can actually push the "dirt" beneath the surface of the aluminum. Ive never had a problem like that, so I dont know if its completly true. I just dont wanna find out the hard way. Maybe matt can give a lil input on that, but I only use scotch brite. Clean the weld area with alcohol too.