How to spray with 350P?

TORQUIN · Jun 14, 2016

I have been reading several threads here regarding the 350P because I want to learn to use mine better. I'm OK with it. Never had a weld break, steel or aluminum, but would like to become better at it wherever possible. I use MIG almost exclusively because I do not understand the advantage to Pulse despite all I have read about it.
On the included charts with the 350P I see that in some places, for thicker steel it says "USE SPRAY" but the manual does not tell me how to set up the machine to "spray". Is this Pulse?

How is spray different from short-circuit? Seems like in all cases that filler wire is gonna have to touch the work to start the arc and then the arc will melt away the filler wire before it can touch the work again, so it's doing what in this scenario, spraying?

I am always open to Pulse, if someone can help me understand why it will be better.

Thanks,
Chris
Millermatic 350P
Synchrowave 351

Shield Arc · Jun 14, 2016

Here is a good read on spray arc welding.
Spray Arc

Stimw · Jun 14, 2016

I don't think my Miller 210 is supposed to spray but it will do something similar.
When I crank it up the wire transfers to the material in a melted form, spraying.
The big difference is in the sound. It goes quiet from the egg-frying sound to the electrical hum sound just like a TIG torch welding.
When it does this it lays a beautiful bead. (like TIG)
The MIG torch and nose cone get very hot too!
It puts out a lot more UV light so if you try it make sure you cover up exposed skin.

Arc weld · Jun 17, 2016

Spray and pulse are 2 different things. For true spray you need a higher concentration of argon/Co2 like 90% or better and you have to have the volts up around 26 or more. If you don't have the higher argon gas and just use C-25 you won't get spray but will get globular transfer. Spray is like it says, it sprays out the contact tip. The wire doesn't hit the puddle/base metal first like short circuit transfer.

TORQUIN · Jun 17, 2016

OK, but I guess my question is how is it set up? I just find it strange that the setup cards included in the welder give suggested setups for Pulse and most short, but in some places just say "Use Spray", which implies that I need to switch a setting someplace to "Spray". It gives no other info about spray usage/setup. This is the main reason I've never used it.
I have a small tank I could get the 90/10 mix in, but I don't know if I want to do that yet, as I'm not sure how to set it up. I have also read that it runs so hot that you can melt the tip of the gun. :hot: Just a little worried about that too.

Thanks,
Chris

Shield Arc · Jun 17, 2016

When I played with spray, I had to switch to my 400-amp Mig gun.
With spray you need really clean metal. At least 90/10 gas. And real high voltage.
This weld was done with .035" Lincoln L-56 Mig wire, and 90/10 gas. See how many volts?

Mark @ Everlast · Jun 17, 2016

Most of the technical information I find says 80/20 Ar/CO2 mix minimum. I personally use a mix from Air Gas that is their proprietary blend which they call C-18. It's 82/18. Works well for me. For heavy spray, I have used my ESAB MIG master 250 for 15 years this way. Can spray at the medium high setting with 60% wire feed speed...whatever that is. .035" wire.

BukitCase · Jun 17, 2016

Even though I don't have a 350P I got curious and downloaded the manual - even THAT doesn't say anything else about spray transfer, so I checked out miller's online mig calculator

MIG Solid-Core Welding Calculator - MillerWelds

For 1/8" and up, it lists both short circuit AND spray parameters...

After seeing/using the gun my mm252 came with, I wouldn't be surprised if that "oversight" is aimed toward NOT having to explain to customers why their mig gun melted

...Steve

Arc weld · Jun 17, 2016

Miller lists 98/2 for spray. I had a guy tell me that less than that you don't get a true spray transfer but a modified spray/globular transfer.

xryan · Jun 17, 2016

To use pulse mode in spray transfer you need 90/10 (ish) blend of gas, personally I usually use an 88/12 blend. DO NOT use 80/20 or 82/18 as stated above by Everlast and Airgas, pretty much all you need to know there...:thumbdown: For Spray transfer you need a higher percentage of argon and typically higher voltage then you would normally use in short circuit. Voltage is to electricity as pressure is to water, the voltage is what is pushing the puddle down into the base metal.

If you have only been using short circuit transfer with your 350P then honestly you have seriously overpaid and are not even beginning to use the full potential of the machine. Once you go pulse you'll never go back, seriously! Penetration almost like stick, smooth spatter free welds, what more could you ask for!

The "MIG" mode chart is telling you to use spray transfer for the thicker materials because spray has more penetration. As is often the case with unskilled weldors, they can lay down a "pretty" bead that is doing nothing more than sticking to the surface of the base metal and can easily be broken off. It's actually quite shocking to them when you show how poor their "weld" is when you hit it with a hammer and peel off their bead.