mig question

[farmboy weldor]

two questions,

i know mig is not recommended for outdoor use but if or when i weld outside can i just turn up the cfh to protect it or is 25 cfh for 75% argon 25% Co2 the only setting

the second question i have is, i went to the empire farm days and visisted the miller exhibit, the sales men told me when i was about to try the 251 out it was on spray arc so i have to push it, is there a way to change to short arc or is it stuck in spray , because i dont prefer to push the weld gun, i pull it, or does it change by itself???

[DDA52]

Yes, you can turn up the gas flow for outside welding. When it is too windy you'll know it quick, fast and in a hurry! If you aren't sure, just turn off the gas and try to weld....same thing. If you turn up the flow, you'll still be able to shield the weld when the wind is within reason. When it isn't, just switch to flux core.

Yes, the 251 will do short circuit transfer. The spray is a transfer in the upper end of the settings and typically is used with different gasses than short arc. BTW, pushing will usually result in better bead profiles with MIG for most weldors. Just a thought.

[walker]

You can turn up the gas, and it helps to soe degree. The best thing I have found is to shield the weld area, even with just a box/piece of wood/custom made screen panels/stack of bricks/etc.
I am late running out the door, but do a search for spray transfer or globular transfer. There was an excellent post a little while back when I asked for definitions of each process. I got a text book in response, litterally, and a good one too.
Good luck.

[Paul Seaman]

Farmboy:
I pull {AKA backhand} nearly all my mig welding except really thin and Aluminum. The pulling will give better penetration and pushing will reduce distortion and burn through in lighter guage materials. Spray is achieved by running the machine hotter and after the arc is established you pull back to about 3/4" gun seperation and the molten puddle will open up and get the move on or you'll have metal on the floor,
****Also this is not possible for out of position work!!
The mm251 should be able to get into spray with c25gas I think, I can't with my mm210 but I can with 98/2.

Weld well,

[farmboy weldor]

thanx for the info it was really helpful especially pjseamen!

[Paul Seaman]

Always glad when I can be of help.

Peace,

[INTP]

...
The mm251 should be able to get into spray with c25gas I think, I can't with my mm210 but I can with 98/2.
...

Even with the power available from the MM251, for mild steel, you need less than 10% CO2 to get spray transfer. Above that and you're likely to get globular transfer.

[Paul Seaman]

I was speaking off the top of my head and you've got me curious so I went back to the book. It says 98Ar-2O2 with .035 or .045 wire. I do appologize for the error.

The book also gives the transition amps required to transition from short arc to spray on .035 wire as 165 amps and .045 wire as 220 amps.

Peace,

[Danny]

Even with the power available from the MM251, for mild steel, you need less than 10% CO2 to get spray transfer. Above that and you're likely to get globular transfer.

The MM 251 has no problem spray arcing 90/10 Co2 with an .035 wire. Believe it or not, it is also capable of producing a lower level spray transfer (spatter free) using C-25 with an .035. with the C-25, you have to max the voltage out, which is 29.5 volts on my unit. Not a spray transfer approach that i recommend just wanted to test the units potential. 90/10, 98/2, or 95/5 would be my recommendation for spray transfer gases with the MM 251.

[Scott V]

The MM 251 has no problem spray arcing 90/10 Co2 with an .035 wire. Believe it or not, it is also capable of producing a lower level spray transfer (spatter free) using C-25 with an .035. with the C-25, you have to max the voltage out, which is 29.5 volts on my unit. Not a spray transfer approach that i recommend just wanted to test the units potential. 90/10, 98/2, or 95/5 would be my recommendation for spray transfer gases with the MM 251.

Dan,
I never used 95/5 but isn't the puddle a little wet for manual mig welding? They use that gas up here for some machine type spray-arc welding.

[Danny]

Dan,
I never used 95/5 but isn't the puddle a little wet for manual mig welding? They use that gas up here for some machine type spray-arc welding.

Scott personally, I wouldn t use the 95/5 because of the high level of oxygen in the mix. I just figured i better mention it because someone else would probably mention that it was a possible gas mix. So, I guess i should admend my previous statement, and state that my true recommendation would be 90/10co2 and 98/2 oxy. As far as the puddle being wet, you should know that we can control how the weld puddle wets out by regulating the arc length. Also placing the part in a flat position pretty much eliminates any undercutting problem. A tight arc length on horizontal fillets should control under cutting on them too.

[cope]

So, I guess i should admend my previous statement, and state that my true recommendation would be 90/10co2 and 98/2 oxy.

Dan,

You have mentioned recently that you felt the MM 210 could not handle 90/10 for spray. I have not tried it , but I do have a full cylinder and want to at least give it a try. I don't remember what other options the dealer has. Is there another Ar/CO2 blend that would work or do you recommend 98/2 Ar/O2?

[Danny]

Dan,

You have mentioned recently that you felt the MM 210 could not handle 90/10 for spray. I have not tried it , but I do have a full cylinder and want to at least give it a try. I don't remember what other options the dealer has. Is there another Ar/CO2 blend that would work or do you recommend 98/2 Ar/O2?

Alan,

Your 210 should spray arc an .030 with the 90/10. I got mine to spray arc an .035 with 90/10, but not to the same arc intensity level that I can with 98/2. I don t know how much your 225 volt input is going to rob from you in the area of out put voltage on tap#7. My input voltage is 240 volts +, and at around 200 to 210 amps my machine outputs around 25 volts on tap #7. So, since my unit might potential output a higher voltage then yours on tap#7 you might not have the same success as me with the .035 and 90/10. However, since an .030 transitions over to spray at a lower level then the .035 I think you 'll be fine with the .030. Just set the machine to tap #7 and around 80 on the wire speed (.030 wire) to start and adjust the wire from there.


As far as spray gases go, my local supplier only carries 98/2oxy, 95/5oxy, 90/10 co2, and 85/15 co2, so they're the only gas mixes that i m familiar with. For your MM 210, out of these, 98/2 would be my recommendation, it is a very easy gas mix to tune the spray arc in with, and produce spatter free welds.

[cope]

Alan,

Your 210 should spray arc an .030 with the 90/10. I got mine to spray arc an .035 with 90/10, but not to the same arc intensity level that I can with 98/2. I don t know how much your 225 volt input is going to rob from you in the area of out put voltage on tap#7. My input voltage is 240 volts +, and at around 200 to 210 amps my machine outputs around 25 volts on tap #7. So, since my unit might potential output a higher voltage then yours on tap#7 you might not have the same success as me with the .035 and 90/10. However, since an .030 transitions over to spray at a lower level then the .035 I think you 'll be fine with the .030. Just set the machine to tap #7 and around 80 on the wire speed (.030 wire) to start and adjust the wire from there.


As far as spray gases go, my local supplier only carries 98/2oxy, 95/5oxy, 90/10 co2, and 85/15 co2, so thwere the only gases that i m familiar with. For your MM 210 out of these, 98/2 would be my recommendation, it is a very easy gas mix to tune the spray arc in with, and produce spatter free welds.

Dan, Thanks. I ran some beads today on 1/4" stock using .035 and 4/40 and got excellent penetration and good looking beads. My 210 doesn't like you to start a weld w/o clipping the wire; it makes a loud snap then settles in to the arc. I nee to get some more steel and try out spray.

[Danny]

Alan,

Just hook up the bottle of 90/10 to your 210 and try it out on some of the scrap that you've been short arcing on. Doing this, well at least answer your question whether or not the 90/10 will work for you. or not t