Spray transfer ??

[gkent]

How can you tell if you're in "spray transfer" mode ?? Is there a physical appearance, different sound, etc?

I have a Miller 252 and normally weld 3/16" mild steel. The recommended settings on the machine for .035 wire are 18.4 volts, 265 amps and these work fine. But is this yielding a "spray transfer" or "short circuit" ?? Oh, gas is 92%/8% which is in the acceptable range for spray transfer.

If I go online, the recommended settings are as follows but aren't even close to the recommended setting on the machine.Volts are much higher but amps much lower.

For "short circuit"
Wire Size & Wire Feed Speed:

.035" (0.9 mm) at 320-340 ipm

.045" (1.1 mm) at 160-175 ipm
Shielding Gas & Voltage Range:

CO₂ 21-22 Volts 75% Argon/25% CO₂: 18-19 Volts
CO₂ gas is economical and has deeper penetration on steel, but may be too hot for thin metal. 75% Argon / 25% CO₂ is better on thin steels, has less spatter and better bead appearance.
Amperage Range:

160-170


For Spray transfer"
Wire Size & Wire Feed Speed:

.035" (0.9 mm) at 360-380 ipm
.045" (1.1 mm) at 185-195 ipm
Shielding Gas & Voltage Range:

98% Argon/2% O₂: 24-25 Volts
Amperage Range:

180-190

[H80N]

Here are some videos that may help

https://www.youtube.com/watch?v=IHkbh0oKv_g

https://www.youtube.com/watch?v=PI3pZxoPRvA

https://www.youtube.com/watch?v=_8RjChhNa1k

[H80N]

The Praxair Shield Gas Manual explains how the different gases affect the weld puddle

http://www.awssection.org/uploads/longisland/files/Praxair_Shielding_Gas_Manual.pdf

[Jerry U]

Spray Transfer with 0.035 solid wire starts at about 175 amps. You're far above that. However a "true" spray has no spatter and at 265 amps the voltage required is probably somewhat higher than 18.4 volts. 92% Argon/8% CO2 is a good Spray Arc mix. However pure Spay Arc with zero spatter sounds good on paper and in a lab! I would watch as those were made and as you got near the end of a plate and/or depending on the fixture you could also get arc blow! The arc might blow back and not only spatter but also make an inferior weld!

I never trusted volt meters since they are often wrong so I would recommend another approach! I called it John Deere crackle spray (because I first observed it at John Deere!) It uses about 1/2 to a volt under a "true spay." There is some fine spatter, in fact a welder may not see it with his dark lens! I used a technique my old boss (who invented plasma cutting/welding) used. When someone is welding I blocked the arc with an 8x10 pad or piece of literature and looked just above it! In fact I use that technique now to look at the quality of weld starts. You can lower the voltage until there is obvious spatter and some shorting then raise it 1/2 to 1 volt!
The arc is very stable and you can hear it crackle, so you can set by sound! It is much less susceptible to arc blow with its shorter arc.
In fact an old lab colleague had a patent on setting Short Arc by sound! Sound can actually be analysed and the machine adjusted accordingly! Today machine manufactures are doing that with microprocessors and electrical signal processing, i.e. volts, amps, current rise time etc..

[gkent]

Well with my current setup as stated in my first post I have VERY LITTLE spatter - what little there is will either fall off with a wire brush or easily scrape off with a piece of metal.

I have no idea how the calculator works but if Miller recommends 24-25 volts for 180-190 amps and I'm running 265 amps then its would seem to me (based on a straight ratio) that I need to crank the volts up to around 35 !!

Currently volts are 7% of amps whereas the Miller calculator above works out to volts being 13%

[gnforge]

I would take H80N advice and watch these videos. They explain a lot and are easy to understand.