Short circuit and spray tranfer.

[Rawr]

Since I'm fairly new.. well ok really new to the trade. lol My teacher wasn't sure and i can't find the answer to an interesting question that no one can seem to answer.
Is there a gas or gas mixture that will work with both Short circuit and Spray transfer obviously for MIG and you'd be welding 1/2" mild steel, butt joints. I know that 92% argon and 8% Co2 work good with spray tranfer.
So basically I'm asking is there a gas mixture that i could use for both modes of tranfer?
I'm only asking, because it seems that it would be more cost effective, to us one cylinder instead of two when you need to use both modes.. ok I'm done babbling now lol

 

[shenion]

1/2" butt joints is a lot for short-arc mode. I would want spray transfer to guarantee good penetration.

1/2" would require more current than you might be able to do with regular wire in short arc. The gas would need to have a high CO2 to keep the heat up and out of globular mode.

I have worked with others that use 75/25 in short arc (at about 175A). The gas is used specifically to prevent the weld from going into globular or spray transfer mode.

That kind of heavy weld is usually done dual-shield. Some dual-shield wire can work with straight CO2 that helps keep costs down.

 

[Rawr]

I see I see said the blind man who walked away with no legs.
What your saying makes a lot of sense to me. You just made it a lil clearer. Thanks =)

 

[shenion]

Welding gases are a big arguing point and not well understood. I have spent a lot of time evaluating mixes. I sometimes change the mix if I am doing vertical up (85/15).

In the UK/Europe, they push tri-mix gases. They seem a bit cleaner but i get spatterless welds with a single mix. Here everyone uses 75/25 as it is cheap (although suppliers still try to push tri-mix.) A good read if you get past the rambling rants is on weldreality.com. He has all kinds of info on gas mixes. He has had a challang out for 7 years for any gas supplier to show any weld benefits from tri-mix. No one has answered his challenge. Then again, the guy has spent his lifetime doing setting up production welding where cost is the biggest issue and a cheaper 2-part mix that passes al AWS requirements will always win out.

A good pulse welder can use one gas as it allows emulating short arc while doing a modified spray transfer. Do not have that kind of equipment but I think one gas can be used in a very large range.

Pules MIG was developed for productivity. It allows spray transfer increased productivity benefits where short arc would be too low a current. It also maintains the short-arc positional benefits where spray arc has problems.