How to Mig Using Spray Transfer – Mig Welding Settings for Spray and Short Circuit
Interested in learning how to mig using spray transfer? Maybe you are not even sure what spray transfer is. Don’t worry. I am about to explain how to mig with spray using down-and-dirty plain talk.
Spray transfer is the kind of MIG welding done in heavy production environments. Like as building railroad box cars, heavy earth-moving equipment, etc…
The reason it is called “spray transfer” is because that is how the molten metal is transferred from the arc to the puddle. Fine droplets of molten metal spray into the puddle and that is what makes the humming sound that is so distinct.
Spray transfer mig welding requires a different shielding gas than what is normally used for short circuit mig welding, ( I will explain short circuit mig later) gas mixtures of 90/10 argon/co2, 95/5 argon/co2, and 98/2 argon/o2 are used for spray transfer mig along with much higher voltage settings.
For.035″ ER70s6 wire ( like Lincoln L56) a typical setting for welding 1/4″ (.250″ or 6mm) steel would be around 25 volts and 350 ipm or inches per minute of wire speed.
So what is meant by short circuit MIG welding?
The term “short circuit” means the wire touches the weld puddle. It short circuits while melting into the puddle and all the while is heating up until it finally blows like a fuse. When that happens it creates the arc that is what makes the heat. This arcing and short-circuiting happens so many times in just one second that the arc sounds like bacon sizzling in a pan.
Short circuit mig uses much lower voltage than spray transfer but is much more versatile for welding thinner metal and welding in all positions.
So for general fabrication, short circuit mig is the way to go because general fabrication requires welding in all positions as well as all thicknesses of steel… all the way from thin sheet metal thickness, up the 1/2″ thick and even thicker.
A good tip for you:
If you want to utilize spray transfer in your shop but don’t want a separate gas mixture, get a cylinder of 85/15 argon/co2. This mixture works well for both so if you have a mig welding machine big enough to handle the high welding currents used with spray mig, all you will need to do is adjust the voltage and wire speed and you will be spraying like a champ.
6 things to remember when learning how to mig with spray transfer:
- push the puddle
- only weld flat and horizontal
- stick out will be longer than with a short circuit
- .045″ wire is probably better than.035″ for most spray applications
- you need a heavy-duty mig machine with high duty cycle to spray mig in production
- use an argon mix with at least 85 % argon
