Interested in learning how to perform spray transfer migration? You may not even be sure what spray transfer is. Don’t worry. I’m about to explain how to mig with spray using down and plain dirty language.
Spray transfer is the type of mig welding that is done in heavy production environments. Such as for the construction of railway cars, heavy earthmoving equipment, etc.
The reason it’s called “spray transfer” is because that’s how molten metal transfers from the arc to the puddle. Fine droplets of molten metal splash into the puddle and that’s what makes the buzz so distinctive.
Spray transfer mig welding requires a different shielding gas than is normally used for short circuit mig welding (later I will explain short circuit mig) gas mixtures of 90/10 argon/co2, 95/5 argon/co2 and 98/2 Argon/o2 is used for mig spray transfer along with much higher voltage settings.
For 035″ ER70s6 wire (such as Lincoln L56), a typical setting for welding 1/4″ (0.250″ or 6mm) steel would be around 25 volts and 350 ipm or inches per minute wire speed.
So what is meant by short circuit mig welding?
The term “short” means that the wire actually touches the weld puddle. It shorts out as it melts in the puddle and all the while it heats up until it finally blows like a fuse. When that happens, the arc is created which is what produces the heat. This arcing and shorting occurs so many times in just one second that the arcing sounds like bacon sizzling in a frying pan.
Short circuit mig uses a much lower voltage than spray transfer, but is much more versatile for welding thinner metals and for welding in all positions.
Therefore, 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… from thin sheet metal, down to 1/ 2″ thick and even thicker. .
Good advice for you:
If you want to use spray transfer in your shop but don’t want a separate gas mix, get an 85/15 argon/co2 cylinder. This mix works well for both, so if you have a mig welding machine large enough to handle the high welding currents used with spray mig, all you need to do is adjust the voltage and wire speed and you’ll be spraying like a champ.
6 things to remember when learning how to perform spray transfer migration:
- push the puddle
- only flat and horizontal welding
- stickout will be longer than with short circuit
- .045″ wire is probably better than .035″ for most spray applications
- you need a heavy duty mig machine with a high duty cycle to spray mig in production
- use an argon mixture with at least 85% argon