MM251 limitations

[10secBu]

I remember Andy once mentioning that certain MM251 settings verged on globular instead of short circuit transfer (I assume globular is bad?).

What would be the machines limitations for short circuit using .035 solid wire and 75/25 gas mix?

What are the recommended parameters/settings for welding 3/8" to 1/2" plate steel for single pass? Is short circuit possible, or is there a different recommended setup?

I read below that "Dan" claimed he would never try and weld a trailer hitch using short circuit which got me to thinking why he would say that? I know spray is a deeper penetrating/more fluid method, but it's my understanding it isn't for all position welding (overhead, etc). I've also never welded Mig in any other setting other than short circuit.

So, please give me the rundown on recommended setup for welding 1/4" and thicker materials, single pass using the MM251.

I've already welded 1/4" single pass with .035" solid wire (75/25 gas mix) with good results, but just in case I need to work on some thicker stuff...

thanks
Todd

[Danny]

Todd

globular transfer isn t necessaryly bad. If the machine is set properly globular transfer will produce weld penetration similar to or better then spray transfer. The problem with globular transfer is that there will alway be some level of spatter left on your material. If you use an .035 E70s-6 and C-25 with spray transfer settings you end up with a fairly stable globular transfer that borders on spray transfer if the voltage is set high enough. Weld penetration is excellent too because of the CO2 content in the shielding gas. No matter what there will still be some spatter though.

I too do weld 1/4" material in the short circuit transfer mode. However due to the potential lack of fusion issues that exist in the short circuit transfer mode I never short arc any project on 1/4" and thicker that could potentially cause the death of a person or animal due to the failure of my weld. So, because of the lack of fusion problem that can occur on 1/4" and thicker in short circuit transfer I would use globular transfer, spray transfer, or a fluxcore wire on a trailer hitch. A trailer hitch is a small enough item that I can rotate into the proper welding position for spray transfer. So, spray transfer would be my first choice on such a small project.

Since you have the C-25 gas the best choice for 1/4" and thicker in all positions with your MM251 would be an .035 all position (E71T-1)gas shielded fluxcore wire. This wire will give you penetration similar to spray transfer with the capability of welding out of position. The deposited weld metal should be almost spatter free too. An all position (E71T-11) self shielded fluxcore would be a good choice for tight areas, because you can remove the nozzle from the gun.

[cope]

Todd, I tried to spray with my PowCon using C-25. I got globular transfer instead. On a test weld 3" long, there were maybe three little beads of splatter. After seeing the prep on your trailer, there's no need to tell you about clean metal. Mill scale adds greatly to the spatter in globular mode. I bought a cylinder of 90%Ar/10%CO2 for spray. I only ran a couple of short beads with it, but it makes pretty, spatter free welds with good penetration on 3/8" material. How's the trailer tool box coming along?

[10secBu]

Thanks for the reply fellas. I'd still hope Andy would add his .02 on the subject.

Cope,

Nope, haven't touched the trailer tool cabinet/box. We just had our second child born 5 weeks ago and Mom is having a tough time with the recovery (c-section). I plan to get back to the work on the box this fall and get it done finally. I basically need to make the hinges, doors, aluminum floors, and skin the outside. I also need to find a source for the latch style I want to use.

I did use the trailer once since completing it and it towed like a dream. It was well balanced and pulled very smoothly most in part due to the torsion axles.

Eventully I'll need to make time to wire the truck for power to the back for the winch hookup.

[ROCK]

OK.......FOR ANDY.......... HIS .02 CENTS WON'T BE AROUND FOR A WEEK OR SO I SEEN SOMETHING CROSS MY DESK SAYING HE WAS ON VACATION....... WELL THAT WAS BEFORE I WENT ON VACATION SO I MIGHT BE LOOSEING IT.... WHEN YOU COME BACK FROM VACATION YOU ALWAYS HAVE THE LEARNING CURVE THING.............. BE SAFE GUYS.....................ROCK
[email protected]

[ASKANDY]

All great answers and you are correct in saying that the spray mode is NOT good for all positions. I like the E71T-1 and it never hurts to "V" groove the weld joint to assure of proper penetration. Even with short arc, good penetration can be achieved up to 3/8 material. There may be a bit more spatter though. An example setting would be .035 wire, 400-500ipm, 22.5-24V 75/25gas or 24-25V CO2. An .045 wire would be a better choice at 210-260ipm.

A-

[HAWK]

Out Of Position Spray

Originally posted by ASKANDY
All great answers and you are correct in saying that the spray mode is NOT good for all positions. I like the E71T-1 and it never hurts to "V" groove the weld joint to assure of proper penetration. Even with short arc, good penetration can be achieved up to 3/8 material. There may be a bit more spatter though. An example setting would be .035 wire, 400-500ipm, 22.5-24V 75/25gas or 24-25V CO2. An .045 wire would be a better choice at 210-260ipm.

A-

Heh Andy,

What about pulsed spray? I used to do a lot of shop fabriation on 1/8 and 1/4" A36 tube and plate. Pulsed spray ran great verticals and horizontals. Even ran a few overheads for test and found good results. I don't remember all the settings. Machine was an XMT 304
with Optima pulser. Gas was a tri mix including He. FOR THE HEAVEY STUFF E71T-1 IS STILL MY CHOICE.

[ASKANDY]

Pulse is great too. The MM251 will not do pulse but if you hold on to your shorts, there might be one coming

A-

[HAWK]

Originally posted by ASKANDY
Pulse is great too. The MM251 will not do pulse but if you hold on to your shorts, there might be one coming

A-

That's one way to put it. Thanks for the sneak preview.

[ROCK]

Well if you look on page 19 of the full line catalogue 2003 it lists a millermatic pulser stock number 903857 and 907074is 30-200 amp range.......... So I'm bak to useing both hands, not holding onto anything...............
Rock........ [email protected]

[dseman]

I heard back in march that miller was working on a competitor to the powermig 300 and that it was to be released this summer. My experience with this info. is that it is usually 2-3 months beyond what the expected date is. So, I'm thinking around the sept/october time frame. Miller already has great multiprocess inverters, so wrapping some blue sheetmetal around a wire feeder and inverter combo. shouldn't be that difficult.

my 2 cents anyway,
-dseman

[HAWK]

Pulsed Spay

Good info and great machines.

IT WILL BE HARD TO BEAT THE PULSTAR 450 IN MY BOOK. A WORKHOUSE OF A MACHINE!

[myhemi]

I don't think that a person should have to worry about what type of transfer he is going to be welding with, as long as you have two other things going for you. 1- metal prep, this is the key to any quality weld. 2- fit up, unless you are working with tolerances and have to worry about distortion, then just make a good clean fit up. the tighter the fit up the stronger the joint.
i passed a cert test with short circuit (vertical 1") ER70S-6 75/25 shield , with proper pre-heat and metal prep this is a strong wire. if you want less spatter than switch to ER70S-4.

[HAWK]

Originally posted by myhemi
I don't think that a person should have to worry about what type of transfer he is going to be welding with, as long as you have two other things going for you. 1- metal prep, this is the key to any quality weld. 2- fit up, unless you are working with tolerances and have to worry about distortion, then just make a good clean fit up. the tighter the fit up the stronger the joint.
i passed a cert test with short circuit (vertical 1") ER70S-6 75/25 shield , with proper pre-heat and metal prep this is a strong wire. if you want less spatter than switch to ER70S-4.

Prep and fit up are definite factors in the weld outcome. I guess worry is not what I was going for-just an awareness of the transfer process and what you are trying to accomplish. Most of my recent certs are 6G position with the 6010 electrode and methane piping. I'm always after 100% penetration no matter what the process or method of transfer. Sorry for any confusion.