Questions on spray mode

[Louie1961]

I'm not familiar with spray transfer, is there a reason that .030 wire isn't listed?

Just a guess, but I bet 030 wire can't carry enough current to achieve spray mode.

[Jack Ryan]

Just a guess, but I bet 030 wire can't carry enough current to achieve spray mode.

Yes, and in addition, spray transfer is usually a hot, high deposition rate and deeply penetrating process which would require a much high wire speed for small diameter wires.

Something with a lower average current (cooler) like pulse spray can use smaller wire.

Jack

[Jack Ryan]

Oh ok. In that case the correct chart would be

Inches	mm	Gas	Current	Current Density
0.035	0.9	98% Ar, 2% O2	165	259 A/mm²
0.045	1.1	98% Ar, 2% O2	220	216 A/mm²
0.035	0.9	95% Ar, 5% O2	155	244 A/mm²
0.045	1.1	95% Ar, 5% O2	200	196 A/mm²
0.035	0.9	92% Ar, 8% O2	175	275 A/mm²
0.045	1.1	92% Ar, 8% O2	225	220 A/mm²

correct?

Yes, approximately that - I used inches converted to mm.

Sorry about that, I should check for typos in spreadsheets as well as forum responses. The assertion remains valid though.

Thanks
Jack

[Oscar]

Yes, approximately that - I used inches converted to mm.

Sorry about that, I should check for typos in spreadsheets as well as forum responses. The assertion remains valid though.

Thanks
Jack

No prob, just wanted to be sure we were thinking the same thing. Good to see another number cruncher here.

[Munkul]

Just a guess, but I bet 030 wire can't carry enough current to achieve spray mode.

Incorrect. You can spray with it, as said earlier in the thread its more about the current density through the wire cross section, not the current itself.

You just wouldn't choose to, as the deposition rate is way too low, so you'd waste heat and make a mess. I'm sure it works in some applications though.

You generally would use bigger wires with pulse spray, because you can control the pinch droplet formation more easily, and you generally want a good deposition rate.

[vwguy3]

When I test drove the Multimatic 220 AC/DC I was curious if it would spray so while I had .030 70S6 in it with argon/CO2/oxygen tri mix I cranked it up and it sprayed just fine. Now it's going to be VERY limited but it did it and that was all I wanted to know.

[Welder Dave]

How much spray Mig do you want to do? I wouldn't even consider an older Millermatic 200 or a newer Multimatic 220 for spray transfer unless you want to burn it up in a hurry. Short welds maybe but you need to match the machine to the welding process the same as you wouldn't want to gouge with a 200 amp stick welder. With the multitude of flux-core wires I'm thinking spray arc is loosing some of it's appeal, like needing more expensive mixed gas. Several flux-core wires run best on straight CO2. In self-shielded flux-core you can get nozzle extensions up to 3 3/4" long for .120" wire. It allows the wire to preheat for extremely fast deposition rates up to 39.5lbs./hr. at 600 amps! That's got to create a lot of heat.

https://www.lincolnelectric.com/asse...3M/c320002.pdf

[metalmagpie]

Two questions:

Is it true that to run spray mode you need a much heavier built MIG gun? A welding school I used to be associated with taught that (for example) you can't run spray mode with a Miller M25 gun for long as it will simply burn up.

In the video above he used 27.5 volts and 600 wire speed when welding 1/8" steel with 90/10 gas, wire thickness not specified but appears to be .035". On all of his experiments he welded 1/8" steel. What would change if he were welding e.g. 3/8" steel? I see how to get into spray mode all the time but nobody talks about how to adjust the spray mode parameters for thicker or thinner steel. Does the thickness even matter?

metalmagpie

[Oscar]

Spray mode is REALLY hot. You'll smoke your MIG gloves if you hold the gun too close to the neck! A lot of MIG guns have thick-walled nozzles, beefier tips, and longer necks. The M25 gun is a 250A gun, but for spray or pulsed-spray you typically have to de-rate the rating to stay on the safe side. 200A or less will help preserve the life of the consumables. Spray transfer has it's own range of permissible WFS/V combinations, depending on what the wire (diameter) can handle. Just like short circuit, you have to "match" the WFS and the V so that it sprays correctly;

https://www.esabna.com/euweb/mig_handbook/592mig3_2.htm

So yes, the base material thicknesses do matter. Thicker steel, then you need more WFS, and a proper corresponding voltage so that you don't get spatter, but not so high that you undercut the whole bead/joint.

[metalmagpie]

I don't use my M25 gun for spray mode. I have a 450A Tregaskiss Toughgun for that.

Thanks for the chart from ESAB. Unfortunately, I don't know the relationship between wire speed on the MM252 and amperage. Is that a simple number to get at?

metalmagpie

Spray mode is REALLY hot. You'll smoke your MIG gloves if you hold the gun too close to the neck! A lot of MIG guns have thick-walled nozzles, beefier tips, and longer necks. The M25 gun is a 250A gun, but for spray or pulsed-spray you typically have to de-rate the rating to stay on the safe side. 200A or less will help preserve the life of the consumables. Spray transfer has it's own range of permissible WFS/V combinations, depending on what the wire (diameter) can handle. Just like short circuit, you have to "match" the WFS and the V so that it sprays correctly;

https://www.esabna.com/euweb/mig_handbook/592mig3_2.htm

So yes, the base material thicknesses do matter. Thicker steel, then you need more WFS, and a proper corresponding voltage so that you don't get spatter, but not so high that you undercut the whole bead/joint.

[Meltedmetal]

https://www.weldingtipsandtricks.com...-basics-3.html

[Louie1961]

I have the newer MDX gun, and I don't do spray as much as pulsed spray. I think the MDX gun can take the pulsed spray for as long as the power supply can keep up. But my gloves are not up to the task. I may have to get one of those back of the hand heat shields.

Thanks for the chart from ESAB. Unfortunately, I don't know the relationship between wire speed on the MM252 and amperage. Is that a simple number to get at?

Use the Miller calculator. It will give you parameters for WFS and voltage for both short circuit and spray transfer: https://www.millerwelds.com/resource...ing-calculator

[Munkul]

Once you're into spray mode, you get enough penetration that overall amps don't matter as much - similar to stick welding. You can travel faster or slower and make a smaller or bigger bead - within reason, you still have to get the weld toes right and avoid cold laps. You can also multi-run to give the weld size you need, which is very common on 3/4" and thicker.

I would use a spray arc around 250-300 amps for most structural steel work. 1mm wire has a practical amperage ceiling of 280-300 amps - you can get it higher, but the wire speeds are crazy. 1.2mm wire will top 400 amps if you need it to, but it's very comfortable around 300 amps.
Once you have the amps up there, you just adjust the voltage to give an arc length is short enough to crackle a bit, but not so short that it spatters. Good rule of thumb IMO, because this usually gives enough voltage to wet the toes out properly as well.

there's no "right" answer as mild carbon steels are quite forgiving this way and a few different approaches can make it work, but stronger steels, thicker and more restrained workpieces need a lot more thought about how to weld, rather than just squirting away. Usually involving pre heat and/or post heat treatment.

[vwguy3]

I don't use my M25 gun for spray mode. I have a 450A Tregaskiss Toughgun for that.

Thanks for the chart from ESAB. Unfortunately, I don't know the relationship between wire speed on the MM252 and amperage. Is that a simple number to get at?

metalmagpie

When I am using argon/CO2/oxygen and.035 S6 wire I set my 252 at 27 volts and 450 inches per minute. If I use 95/5 argon/oxygen it will spray at about 26/26-1/2 volts.

[metalmagpie]

https://www.weldingtipsandtricks.com...-basics-3.html

Interesting link, but only applicable to short circuit mode and here we're discussing spray mode.

[Meltedmetal]

Interesting link, but only applicable to short circuit mode and here we're discussing spray mode.

"I don't know the relationship between wire speed on the MM252 and amperage. Is that a simple number to get at?"

I beg to differ. The relationship doesn't change for a given wire size. Miller thinks it is a factor of 2 for .035 wire Jody thinks it is 1.6. If you look at the calculator Louis1961 linked you will find that the recommendations for short circuit and spray conform to the same ratio for a given wire size. Yes spray is higher current achieved by higher wire feed speed. In .035 wire the current is 2X the wire speed inn inches. Obviously the voltage and gas type are also factors.

[MinnesotaDave]

Oh ok. In that case the correct chart would be

Inches	mm	Gas	Current	Current Density
0.035	0.9	98% Ar, 2% O2	165	259 A/mm²
0.045	1.1	98% Ar, 2% O2	220	216 A/mm²
0.035	0.9	95% Ar, 5% O2	155	244 A/mm²
0.045	1.1	95% Ar, 5% O2	200	196 A/mm²
0.035	0.9	92% Ar, 8% O2	175	275 A/mm²
0.045	1.1	92% Ar, 8% O2	225	220 A/mm²

correct?

For your 0.9mm wire I got the same answers.
I did not for your 1.1mm wire. I think you used 1.14mm instead of 1.1mm?

[ttoks]

Just a guess, but I bet 030 wire can't carry enough current to achieve spray mode.

Yes, and in addition, spray transfer is usually a hot, high deposition rate and deeply penetrating process which would require a much high wire speed for small diameter wires.

Something with a lower average current (cooler) like pulse spray can use smaller wire.

Jack

If that's the case this sprayer transfer weld I did with .030 with 93% Ar 5% Co2 2% O2 gas done with a EWM Picomig 180 at 600 IPM and 28 volts shouldn't be possible.



I am one of those the suggests that sprayer transfer is indeed possible with C25 gas, it requires way higher currant and voltage to get it to work, but it does work

[Oscar]

For your 0.9mm wire I got the same answers.
I did not for your 1.1mm wire. I think you used 1.14mm instead of 1.1mm?

Correct, I converted 0.045" to 1.14mm. Some places list it as 1.2mm but if we are to believe the 0.045" number, it works out to 1.14mm.

[And256]

Or at least a variation on a theme.

It is not so much the current that (helps) promote the transition to spray transfer, but the current density. Flux core wire has a smaller cross sectional area than the same diameter solid wire so it gets keen to transfer to spray earlier - so to speak. High argon shielding gases reduce the current density at the transition to spray transfer.

In addition, the filler often contains materials that will promote spray transfer. I think a large proportion of flux cored wires is designed for spray transfer.

I have no practical experience welding with straight CO2.

Jack

From what I know the dual-shielded wires use the globular mode since it's almost impossible to go into spray mode with C25 not to mention 100% CO2.
It's the flux material that reduces the excessive spatter of globular mode and gives fine results.

[And256]

If that's the case this sprayer transfer weld I did with .030 with 93% Ar 5% Co2 2% O2 gas done with a EWM Picomig 180 at 600 IPM and 28 volts shouldn't be possible.



I am one of those the suggests that sprayer transfer is indeed possible with C25 gas, it requires way higher currant and voltage to get it to work, but it does work

I recall reading that it's technically possible to achieve spray mode with C25 if you weld with at least 350A, but I don't remember the wire diameter. Still, the arc will be unstable without the fine results of a healthy spray mode.