spray transfer min. current - 1.0mm and 1.2mm steel wire

[Richard Smith]

Hi there

Is the transition to spray transfer at a lower current with a smaller
1.0mm diameter (39thou) wire than with 1.2mm (47thou) wire?

With Ar-15%CO2 I reckon it's
1.2mm dia -> 240A
1.0mm dia -> 220A

What do you reckon?

Reason for asking is, at lower thicknesses, that might be enough
difference to enable spray transfer to be retained, not some other
mode.
It seemed to make a useful difference for box sections, where their
structural efficiency results in wall thicknesses in millimetres (less
than 3/8inch). So dropping spray transition to near 200A makes spray
available for most work with SHS's and RHS's.

I've never thought about it until recently because quite a lot of
air-cooled torches can take 240A spray with 1.2mm dia wire, but
overheat and ****-out with 1.0mm dia wire.
Which can be understood
1/1.2 of contacting electricity pick up surface
1.2^2/1 = 1.44/1 wire feed speed increase

So in general you'd want 1.2mm dia wire when "spraying".

But with a water-cooled torch (gun) on an industrial machine - the
torch can take spray with 1.0mm dia wire, and obtaining spray at a
lower Amps might make that crucial difference enabling clean, smooth,
efficient, fast spray transfer to be used on lower thicknesses.

Do you experience that this small extra domain of spray at the lower
range can be useful??

[Randy333]

On Tue, 23 Nov 2021 07:06:50 +0000, Richard Smith <nu...@void.com>
wrote:

Not sure about currents, but I generally spray with .045" wire
(1.143mm) My machine does not have any meters on it. I have used
.030" and .035" wire and sucessfully used spray transfer and I have an
air cooled gun.

I was told when I bought the welder I had to use gas with a max of 10%
CO2 or I would not be able to get spray transfer to work. My standard
is 92-8 gas.

Randy

[Richard Smith]

> My standard is 92-8 gas.

I wish I could try it.
How is it in dip transfer for thinner sections and positional welding?