[Kryptinite Engines]

Hi guy's
Just found this site,great place,got a problem and maybe someone here can help me out.The problem is when welding aluminum on the very first start of the arc it leaves a black sooty deposit at the first puddle and no more after that,i have tried everything and changed everything,filler,tungston,gas pressure,cups,you name it,i,m beginning to think it's my machine,300 amp Airco square wave.Anyone ever ran into this,any help would be greatly appreciated.

Thanks Dean

[jakeru]

Take a look at your tungsten. It should be a shiny or dull metallic color, not blue or other rainbow colors, etc. Rainbow colors on the tungsten indicate an oxidized tungsten. If you strike an arc with an oxidized tungsten it will blow that black smut onto the surface at the beginning of the arc; it will usually will "burn off" quite quickly.

You can fix this by increasing pre-flow (if its set inadequately), increasing post-flow (if its set inadequately), or just making sure to hold your torch still during post-flow phase, or perhaps you are just running too much tungsten stick-out for your cup size (easiest fix for that is to run less tungsten stick-out.)

The only other thing I can think of that blows the black smut is when there is aluminum contaminating your tungsten. That can blow black smut around your work also when you run the arc, but usually it will keep blowing black until the aluminum is burned off. (changing tungstens at this point is a good idea.) You can grind the aluminum contamination off your tungsten and use it again.

[Kryptinite Engines]

Thanks for getting back with this information,i'll give your suggestions a try and get back with the results.

Thanks Dean