gas question

[mikeb]

Today I welded 1/2" plate fillet welds with .045 wire. To spray weld, the chart said to use 100% CO2, but I only had stargon. Why do certain gases allow spray welding?

[Hobart Expert Dave]

I dont believe you can spray weld with 100% CO2. Normally it takes a high content of Argon to get into a spray. The Argon alows the puddle to get more fluid so you can get the weld into a spray. 100% CO2 is for short arc welding. Lets see What others have to say.
Thanks
Dave Evans

[chip hayden]

as far as i know, dave has it right. argon is the only shielding gas that allows true spray tranfer welding. it has to do with it's ionization potential[which is a function of the arc voltage] and how tightly it constricts the arc column. you can mix other gases with argon and still spray but it takes more power. i believe i recall seeing graphs with the ratios and voltages for spray transfer but i can't put my hands on one at the moment.

[Rocky D]

Two mixes that work great for spray are 98 % AR and 2% Oxygen, and 98 % AR 2 % CO2 . Most guys like the oxy mix best, however I have used the argon CO2 mix quite extensively, and it works for me. Do a search here on "spray" , and you will find some neat pictures on a job I did a few months ago.

[mikeb]

What does spray transfer welding sound like comapred to globular transfer? There are many sounds associated with MIG welding compared to other processes.

[Rocky D]

Originally posted by mikeb
What does spray transfer welding sound like comapred to globular transfer? There are many sounds associated with MIG welding compared to other processes.

Short arc = crackle, globular = ploop, ploop, spray = hisss