Welding Tips and Tricks

I have a miller 252 mig welder, and I've been trying to set it up for spray transfer to weld some 3/8 plate. How should I go about doing this? Right now the 252 has .035 and I believe it is er70s-6, and c-25 gas. Will these work, or should i get some gas with a higher argon percentage? I had also read that the original m25 gun won't hold up to spray transfer, is this true? Other than that, just looking for any instruction, or tips ya'll can give me. Thanks!

Brennan Clark wrote:I have a miller 252 mig welder, and I've been trying to set it up for spray transfer to weld some 3/8 plate. How should I go about doing this? Right now the 252 has .035 and I believe it is er70s-6, and c-25 gas. Will these work, or should i get some gas with a higher argon percentage? I had also read that the original m25 gun won't hold up to spray transfer, is this true? Other than that, just looking for any instruction, or tips ya'll can give me. Thanks!

I use 98%argon/2%oxygen for spray transfer on ours, have used .035" but you have to crank up the amps to high to keep up and get a decent fill. You'll be happier with .045". That welder goes into spray after 24 volts. Do some test pieces to dial your settings in, keep the stickout about 1" and burn it in. We still have the stock m25 gun but I have melted the black plastic gaskets at the nozzle. I weld 3/8" a500 steel to 1/2" a500 with 26v and 330a.

You ll know when its in spray, quiet hissing sound while welding.

I'd reccomend duel-shield fluxcore.

To get into spray arc you need a 85-90 argon gas. A c25 will not put you into a spray arc.

Will pure argon work, or does it need to be an Ar/O2 mix?
Also for a vertical weld with spray transfer is it best to run uphill or downhill? Thanks

Brennan Clark wrote:Will pure argon work, or does it need to be an Ar/O2 mix?
Also for a vertical weld with spray transfer is it best to run uphill or downhill? Thanks

Spray is a very poor choice for vertical welding.
Do your homework and get some .045 duel shield flux core.
You can use your 75/25 with it and weld all all positions unlimited thickness with one size wire and gas type.

I would'nt use & don't think pure argon is ever recommended for steel - for any given wire size as you continue to raise heat input it will go from dip transfer thru globular to spray - the exact point this occurs will vary with wire size & gas mix - you can & will get spray transfer with high(ish) % of CO2 but it will require more voltage - I can't comment on 75 / 25 as it's not used or available as the main suppliers here state there is no gain using over 20% so I assume it's done for cost reasons - over here essentially 95 / 5 is used for sheet metal & very light fabrication & 80 / 20 for normal shop use - ( rounded up as there is a few % of other components added for various reasons we don't really need to know ) not sure what voltage range your machine covers but in theory it should do spray - hopefully others will chime in with more relevant experience of your machine & gas combination - with regards to vertical it is not usually if ever done with conventional spray transfer as it is too hard to control - on more advanced machines spray pulse however can & would work mostly vertical up - only time I've been asked to do it downhill was on an open outside corner joint & that was more to save changing machine settings.

Agreed, you won't do vertical up with spray transfer, I've rolled around corners in a down hill motion but it can drop out real fast.

I use spray welding some structural cross members, reposition the piece so I weld in a flat position if at all possible.

Pure argon will cause under cutting. The reason co2 is added, would be to help with the wetting of the weld. It gets rid of the under cutting. In reverse the argon helps the c02 not spatter etc. The literature we use states a true spray arc needs 90 percent ish argon. The argon gas accepts the electrical charge witch is required for true spray. I remember 30 years ago when gmaw (co2) was starting to be used in the shops around my area they would turn it up and it was actually a buried arc. Very high amperage was used. Now I am just going by the literature. Could someone point me to some literature that states spray arc is possible with75/25. sorry for the type o.

Pure argon can be used but you will have serious LOF issues and in turn no depth of fusion. I did some weld samples using pure argon and the bends didn't get very far at all before the base metal basically pulled away from the weld metal. I cannot recommend it ever be used for mig welding.

To answer the question of spray transfer. I have a 252 and it will spray transfer just fine with a 90% argon/10% CO2 mix. If you go by the AWS definition of spray you in theory csn achieve it with your 75/25 but it is not a "true" spray and it is not practical. You will also, depending on your settings, reduce your efficiency of the amount of wire your actually putting down due to spatter and smoke. As mentioned, generally spray transfer is achieved in the 24-26 volt range, depending on wire diameter. I see no reason to jump to a cored wire but I recommend jumping up to .045 as that will be more efficient than your .035. The cored will not be as efficient as the solid .045 as well.
Jonathan

80% argon is required for spray.
Spray is limited to flat and horizontal fillets.
You can spray with 90/10 and also short circuit with 90/10.
If you need to weld in positions other than flat and horizontal and cannot use short circuit then you need to consider FCAW-gas shielded.
GMAW short circuit for thinner metals- all positions.
FCAW gas shielded for thicker metals- all positions.
One shielding gas 75/25.

Thanks for all of the replies. The reason I'm wondering, is I'm working on getting my aws level one certification, and I'd like to do some practicing at my house. It's been a while since I've seen the test spec sheets, so I can't comment on whether a specific gas mixture, or wire is mandated, however I do believe there is a 3f vertical fillet weld, but I could be mistaken.

Are you referring to a SENSE Level One certification?

Regardless, spray transfer is limited to flat and horizontal fillets.

Heyyyyyyy, what happens if you use or try using all co2 for spray transfer? And why is it limited to those positions?

iwhen i spray arc i run the amps up to about 24.9 to 26 the wire speed is around 290 to 315 with .045. and thats with 75/25. mix gas. every machine runs a bit hotter or colder but those setting will get you really close to what you going after.