[under the hood]

Ok let me share tonight's nightmare with you guys and maybe you can shed some light on my dilemma! I'm attempting to weld 18 gage aluminum.047 approx. ok here is my set up first 50-55 amps approx. 1/16 filler of 4043, 6 and a 7 cup tried both. 14# of gas. I was using an .030 and a 1/16 tungsten tried both 1.5 lanthenated to b exact
Now the material was something I picked up at the local steel house in the cut off section would like to point out that this has a white paint on the back of it which I did clean away from weld zone prior to welding, and it also very shiny almost like a stainless look. I did all the right stuff prior to welding wire brush (designated for alum. Only) wiped with alcohol along with filler rod as well.
Now the problem, I can't get it to weld for $hit!!! The minute I hit the pedal I immediately get that black soot around the weld and also get a brownish tint around that like there is something in the finish affecting things , the tungsten is not real thrilled either. Is this some goofy type of alum. Or am i missing something?
To make sure it was not my set up I tried on a different piece I had laying from another project same thickness and amps and all went well I got that nice scrubbing affect while welding this and that to is something I could not get on the above stated. Kinda scratching my head on this guys any input would b great thanks, also would like to point out my machine is a diversion 180 thanks guys,Eric

[TamJeff]

What are you using for a machine and for gas and has the gas worked on something else before this? Is the brown a tint of the metal color itself, or brown smoke stain on it?

[under the hood]

Gas is argon, machine is a diversion 180 I'm thinking brown tint is due to paint on back side heating up maybe? Like I stated above I did in fact weld on some other aluminum I had with that same set up with good results. It just seems to me there is something in the material itself maybe , like I said getting that black soot around weld area no matter what. Gonna maybe try and grind a bit on surface to see if there is something on that top layer my cleaner and wire brush are not getting?

[TamJeff]

In that situation I would try a sander on the metal to see if I could expose another layer. May be clear powder coating or something. Instead of alcohol, acetone. Acetone will lift most paints.

[Nils]

Your material may be a cladding that's used in the lighting industry. Sounds like there's a plated film on it. Tamjeff's suggestion of sanding off the area to be welded sounds like a solid approach. My suggestion is to shit-can this material with its painted side and all and don't look back. Doesn't sound like ur saving anything.

[nathan]

I've been told (and experienced) that you're not supposed to grind aluminum. We had a part come through that I messed up and had to grind the weld off. This made the material unweldable. It wouldn't take filler rod at all, it would ball up on the surface, while the base metal was clearly molten. The base metal had that "super bad oxidation" look to it whenever it was molten.

[TamJeff]

I've been told (and experienced) that you're not supposed to grind aluminum. We had a part come through that I messed up and had to grind the weld off. This made the material unweldable. It wouldn't take filler rod at all, it would ball up on the surface, while the base metal was clearly molten. The base metal had that "super bad oxidation" look to it whenever it was molten.

Grinding aluminum is not ideal, but necessary much of the time. I have to cut/grind welds off of aluminum all the time. If you look on the weld chart for anodized aluminum, it is listed as a non-weldable alloy, yet we weld it beautifully and as a process all it's own. In the industry, you don't scrap mistakes, you repair them and start over. I use what is known as a milk wheel for grinding aluminum that is made for non-ferrous metals.

With much of the import extrusion we get these days, surfacing, is pretty going to be a part of the equation if it is anything that will be decorative or even painted. I often have to DA the entire surfaces prior to fitting or welding. It would be nice if the brains behind all of these ideas would notice the false economy behind such notions as the cost of abrasives and labor often cancel the initial savings. I will often save 1/4th the abrasives and labor dressing domestic over import, but these spend thrift phd guys can't see past the end of the dollar signs at the tip of their noses.

[timpane]

Sounds like there's a plated film on it. Tamjeff's suggestion of sanding off the area to be welded sounds like a solid approach. My suggestion is to shit-can this material with its painted side and all and don't look back. Doesn't sound like ur saving anything.

[Otto Nobedder]

Nils,

You have an admirer!

timpane parroted your suggestion verbatim after the lighting industry mention.

timpane may be an autoresponder testing for a spam-storm? I hope not, but to use the exact same words, punctuation, and grammer?

We'll see.

Steve S