[Barry_ward]

Hey D,

Try new gas.

I've seen two different bottles of gas that did not contain 100% Argon. (but should have)

When I had the laser business it was easy to check (we'd just squirt it into a vacuum, ionize it, and look at the spectrum) pure argon produces a distince lavender glow consisting of spectral lines including 488 and 514nm (and lots of others).

CO2 and Nitrogen both seem to have a way into welding gas mixes and both will kill your welds.

I also second the recomendation of Helium mix. Remember that this kind of welding is sometimes called "Heli-Arc"

Best regards,

Barry

[Mortek]

sorry

[Barry_ward]

Mortek,

Your focus was not bad and was correct and imformative.

"I guess no one understands what I was trying to convey here. I use straight helium and dc straight polarity to weld thick aluminum because it ionizes hotter than argon. I am not the inventor of this process, I was simply passing it along to those who have lower amperage machines as a means of welding thicker cross sections.

Two reasons it runs hotter:
DC (tungsten negative) sends the ion stream in the direction the work.
AC (typical heliarc) heats the work 50% of the AC cycle and the tungsten 50% (the other 1/2 cycle) of the cycle.

Second reason:
Helium is a high (electrical) resistance gas which yields signifiacntly more heat compared to Argon.

Pure helium is tought to keep "lit" so it's mixed with argon which lowers its resistance.

[damae]

Mortek, those are some impressive welds! I guess I'll have to give it a try with DC. Do I need to use HF start?

Barry, I'll get some Helium on my next trip to the welding supply shop and see how it does.

[Barry_ward]

D,

Get the 50-50 mix. Don't just take the first dufuses answer at the welding supply if it sound wrong.

There is a lot of info on mixes at http://www.praxair.com/praxair.nsf/A...2570A60020CFAE

B

[thkoutsidthebox]

Sorry,
Those are pictures of the same bead, shown before brushing and then after.

Yes, and its a nice bead.....but the first one needs to be brushed!