The Welding Thread

[4x4_e30]

I got a question for all you gurus. I'm in the process of converting a 1974 Miller DialArc 250 AC/DC to tig. I'm wondering if the regular sine wave 50/50 AC output will work for aluminum once I get a high frequency box. I'm aware that it's not going to be optimal but I got the welder for free, so I'm trying to make it work.

[marshallnoise]

This is very very true. (One of my brothers fav anecdotes about today's college students) A few years ago while my brother was in the very beginning of his Mech Engineer studies. His class was set into groups of 4, for a project, my brother being very mechanically inclined and with a garage full of tools, years in hobbiest car fabrication and working in a machine shops R/D prototyping department can build you just about anything you want from scratch or fix anything from your Ipod to your transmission. (yes hes a number of years older than your average college student)

Well the group meets for a design meeting in my brothers garage, of course hes already procured supplies, parts and PLC's form his work suppliers on demo's or old shit laying around the shop. So anyway 1 of the 3 perspective future engineers asks what kind of glue they are going to use to make the metal stick together, with a Miller TIG machine sitting 2 feet to his right. The others are also interested in this prospect as well. Well with out too much hesitation my brother grabs a couple of pieces of scrap AL laying on his work bench his hood and torch are laying there as well (as he was working on inter-cooler piping for a friend when they showed up ) flips the TIG on and proceeds to GLUE the scrap together. After the welding demonstration grabs it with a gloved hand and whacks it on the bench and then throws it down on the floor and of course it holds up. The kids that have no clue what the pointy end of a screwdriver is for are amazed that this kind of VOODO exists and that someone who is only 4 years older than them can do it and has the stuff to do it in their own home shop.

Great story!

Someone answer 4x4's question. I don't want it to be lost because of my comment.

[pantelones]

Well the group meets for a design meeting in my brothers garage, of course hes already procured supplies, parts and PLC's form his work suppliers on demo's or old shit laying around the shop. So anyway 1 of the 3 perspective future engineers asks what kind of glue they are going to use to make the metal stick together, with a Miller TIG machine sitting 2 feet to his right. The others are also interested in this prospect as well. Well with out too much hesitation my brother grabs a couple of pieces of scrap AL laying on his work bench his hood and torch are laying there as well (as he was working on inter-cooler piping for a friend when they showed up ) flips the TIG on and proceeds to GLUE the scrap together. After the welding demonstration grabs it with a gloved hand and whacks it on the bench and then throws it down on the floor and of course it holds up. The kids that have no clue what the pointy end of a screwdriver is for are amazed that this kind of VOODO exists and that someone who is only 4 years older than them can do it and has the stuff to do it in their own home shop.

I was talking to a friend of mine earlier today about the little stainless project I am working on, and I just about lost him when I started talking about back-purging and how the flux worked...

I got a question for all you gurus. I'm in the process of converting a 1974 Miller DialArc 250 AC/DC to tig. I'm wondering if the regular sine wave 50/50 AC output will work for aluminum once I get a high frequency box. I'm aware that it's not going to be optimal but I got the welder for free, so I'm trying to make it work.

To my knowledge...

But if you want to TIG aluminum you should find a DialArc HF model. It will have the high frequency generator built-in that will allow you weld aluminum and other metals on AC. You could buy an air cooled TIG torch for this one and scratch start TIG weld in DC on steel, but you won't be able to do aluminum on AC without the high frequency generator.

I'm not sure if the HF generator is the "box" you are talking about, but it sounds like to need the HF to do aluminum.

Actually, just adding a High Frequency box will not turn a DC welder into an AC welder.
High Freq is for ease of starting, for longer life between sharpening tungstens, on DC.

You need AC for aluminum. And you usually use a High Freq box on "continuous" with the AC.

For steel and non-aluminum non-ferrous, you can just do scratch start air cooled- you just need a tank of argon, a torch, and a flow meter or regulator.

[pantelones]

I got around to testing the stainless flux, and I was not happy with the results... This is strictly for repair work, when you just cannot gas purge.

IMG_0159 by Los Pantelones!, on Flickr

IMG_0165 by Los Pantelones!, on Flickr

This is what I was not happy about...

IMG_0164 by Los Pantelones!, on Flickr

The black stuff is what it is supposed to do, and the pores section toward the left is NOT ...

IMG_0162 by Los Pantelones!, on Flickr

The butt joint was better on the inside, but had little dingle-berries on the surface. (probably in the weld too...) I brushed it to see if they would come off and they seem to be stuck.

IMG_0169 by Los Pantelones!, on Flickr

Now I'll just wait until the regulator comes into stock... Anyone want some stainless flux? ;)

[mrsleeve]

Looks like your running a little hot on the butt welds and did you try and chip that slag off vs just a brush...... Were you power brushing or just hand brushing try power brushing where you can get at it. I think you might have better results that you think you do after you get all that flux slag off the top. I think some of that poreing your getting on the surface is a result of what the flux is supposed to do, and protect the puddle as it cools but let the gas escape the metal to the atmosphere as well. I have never really been around a flux process like this.

Closest thing I have dealt with to a process like this is Sub Arc (submerged arc) on double joint racks and large volume pipe fab facilitates and there is a little fairly tough glassy, porous looking flux slag when you get the bulk of the unaffected flux off the top of the weld pass not that dissimilar to what you have going on up there

[pantelones]

Looks like your running a little hot on the butt welds and did you try and chip that slag off vs just a brush...... Were you power brushing or just hand brushing try power brushing where you can get at it. I think you might have better results that you think you do after you get all that flux slag off the top. I think some of that poreing your getting on the surface is a result of what the flux is supposed to do, and protect the puddle as it cools but let the gas escape the metal to the atmosphere as well. I have never really been around a flux process like this.

As I was uploading the photos I noticed that the HAZ was really wide compared to when I tried to purge. I ran 58 amps (16ga tube) for both, and both were basically filler-less... I usually stay at 3/4 throttle and drop from there, but maybe I used less the first time? Aiming for 45 is about right, right? haha And it was machine brushed, that's why I am not too happy with it.

The flux is supposed to completely protect the puddle... I think that the paste was drying too quickly, and wasn't working quite as well as in the test. Maybe came loose, and wasn't sealing air tight? I ran one of my test beads half-in/out of the flux, and the portion that ran out looks like the back of the fillet.

The beads below are no carbide (sheet was flat on table), carbide, (sheet warped), and flux (suspended in jig)

IMG_0171 by Los Pantelones!, on Flickr

And the flux bead on top... I have got to start using a stone or chalk line :drink:
IMG_0170 by Los Pantelones!, on Flickr

[IronFreak]

Going to drop the final welds on this......that collector is going to be a sonofa.....

[marshallnoise]

IronFreak, that thing is rad. Massive flanges!

I am getting amped for my .040 collet to arrive. I may try a DIY pedal for my little Everlast.

[marshallnoise]

Got the collets! Going to see if I can see how it works out this weekend.

Is it necessary to sharpen a .040 tungsten by chance?

[ForcedFirebird]

I sharpen them all, and on really thin stuff, polish it.

[marshallnoise]

I sharpen them all, and on really thin stuff, polish it.

Roger that.

[IronFreak]

Cool little trick I do, I'll post a video later. Get a cordless drill, load up a piece of tungsten, turn on the bench grinder and sharpen away. controls the point, keeps it nice and even and gets all your grind marks running in the same direction.

[Northern]

that collector is going to be a sonofa.....

I was actually wondering about that lol. how are you going to get inside? do it from the top?

[maniacmatt]

I'm a few posts late to the party on this one but I can confirm continuous high frequency current is absolutely necessary for AC welding on aluminum.

The reason being is you will get arc rectification without it. With the HF current the arc is unable to switch polarity meaning the electrode positive half cycle of the AC wave will essentially stop happening. Without that there is nothing to strip the aluminum oxide from the surface of your piece and you will be unable to weld it

[ForcedFirebird]

Cool little trick I do, I'll post a video later. Get a cordless drill, load up a piece of tungsten, turn on the bench grinder and sharpen away. controls the point, keeps it nice and even and gets all your grind marks running in the same direction.

Been doing this for years :)

Polish it with some fine paper, and watch how controlled you can be at low amps. I've welded razor blades and beer cans that way - had a very stable arc down to ~5amps.