TIG Welding aluminum

[FoMoCo]

Hey all im have a difficult time welding on some cast aluminum. I trying to fill a 1/4 inch gap in a carb spacer that would otherwise act as a vacuum passage. Neigther the cast, or the consumable will puddle. It makes a black gloppy mess. No penetration and not clean at all. I sand blasted the cast part and stared with a new balled end pure tungstin. I'm running the welder in AC mode an it refuses to start an arc. It's a Miller Syncro 180SD if that helps. Welding stainless and mild is great but lately im over looking something when welding AL.

Nick

[spartman]

Maybe you need to clean the part with acid???

[black70cs]

Castings can be a problem, some weld good and some horrible, depends how much sand is in it from the cast. Did you take off the "skin", try wire brushing the crap out of it, have you tried it on a clean piece of scrap? Also you want to run your gas on Alum at about 30, matl. turning black is dirty matl. or not enough shielding gas. Another issue could be the cup your using not being large enough. What size tungsten? I'm not familiar with a snyc. 180, I use a old 300 at work, You could also play with the AC balance little. Hope this helps.
Charlie

[Leadfoot]

well at the foundry we use a mig, and knowing what grade of aluminum you are playing with helps, say if you got some mag. in there when you try welding it can mess u up/ burn. are you seeing bright sparks or white flex? if so its got a high mag. content and you need more gas to shield it.


and it being a carb spacer the aluminum it will be penetrated with fuel, and likely a mag alloy. what I would do is use a mig at twice the heat as steel, with a fine wire. and lots of shield gas and I find pre heating aluminium helps, specially on fuel contaminated metals.

[FoMoCo]

I'll try a 3/m Scotchbrite disk to smooth it out and bake it in the powdercoating oven. I'm Getting the arc is the biggest headach with this project. I created a clean balled end but it sounds like it trying to electricuit the part in stead of arc.
Thanks for the tips.

Nick

[black70cs]

Have you tryed it on a piece of clean scrap? Have you ever welded alum with it? If you've never welded Alum. with a squarewave machine, it makes all kinds of racket. I suggest you try a piece of clean scrap, eliminate the obvious (faulty machine, gas coverage ) play with the controls, there should be some sort of AC balance turn it up or down and see what it does to the arc, I know on a newer mach. it makes a huge difference. If you get it to weld clean on scrap and not on on the cast, then it's a cast issue. Might want to check all of your gas connections too.
Charlie

[Carbide Cowboy]

Are you using pure argon?

[CA180]

Also a good idea to pre heat cast aluminum before welding... Cant remember where i read that,,, but i know i did.

Also check out this link. May help

http://www.lincolnelectric.com/knowledg ... igalum.asp

[Kurt Combs]

I was a welder for many years, but did very little aluminum. The theories I heard were clean as you can get it and hot as hell. We would cover the part with smoke from an acetylene torch and then heat it until the soot burned off. There are more technical ways to determine whether or not you have the part to the correct heat, check with your welding supply house for that info. Just remember that aluminum will draw the heat away for the zone you are trying to weld unless the rest of the part is already hot. Cool the part slowly or you will get cracks.

[Badd F100]

Almost always a black sooty deposit on aluminum is 1 of two things, contaminated gas, or contaminated tungsten. If it isnt the tungsten, make sure the gas is pure argon. Had it happen to me once... Very bad. I was sold a Nitrogen tank, that had been filled with argon. Would not weld aluminum, but every other metal, stainless, mild steel etc, would weld beautifully. Never fully purged the bottle, even after 4 tries. Bought a new bottle of argon, problem solved. Happened again 2 years later, they filled my tank with contaminated gas.

[averagef250]

I've got the same machine. The 180SD. It's pretty good, but like Ranchero said squarewaves weld different. I prefer the old machines honestly, but got such a good deal ($1200 with a bottle and cart) on the 180 brand new I couldn't pass it up.

On the 180 play with the AC balance knob. I find the squarewave will weld even the dirtiest aluminum if you crank up the heat and turn the balance knob to "max clean". The welds look like crap on max clean, but I can't imagine it matters on a carb spacer.

Another trick is to crank it up to max clean and just go over the base metal a whole bunch without filler.

If that doesn't work JB weld it.

I ran out of Argon a few months ago mid-project and switched the 75/25 tank on to try and finish. Nope. Not gonna happen. Gotta have straight argon for Al welding.