View Full Version : Woopee, MM251, now what??
10-31-2002, 07:36 PM
Have just picked up my new Millermatic 251. Gotta start a project over the weekend welding up a square base out of 12"/19 lb Ibeam. the ibeam is nominally a heavy 5/16" to 3/8" thickness mild steel. How much amperage, and what feed speed. Also have 2 150cf 88/12 Argon/CO2 bottles, how much weld time with each bottle(provided I can remember to shut the **** valve off) Thanks, tynwood
11-01-2002, 11:02 AM
I'm not sure what exact type of project you are working on but just from my experience, with what thicknesses you have stated, I wouldn't think about hardwire MIG welding that. Your project seems quite "structural". I would check into a dual-shield wire that will coincide with what shielding gas you have. You can get fairly large diameter wire in a fairly good selection of wires that will suit your application. The reason I wouldn't use just mig, is that you are more than likely going to need to do multiple passes, and depending on your experience and skill, you take a risk of cold lapping your welds. If you go with dual shield, or even just a good inner shield wire, the welding characteristics can be quite similar to that of just Spray-Arc. I would suggest spray arc, but you would have to go buy another bottle of shielding gas that I believe, not certain, has a certain amount of O2 in it, around 2%??.... Also spray arc limits your welding position ability, a very important aspect often overlooked for out of position welding projects when considering spray arc. There are all position wires available in dual shielded wires. I just go with a dual shield wire because I can switch back and forth from hard wire to flux cored dual shielded wire and not have to worry about multiple bottles of shielding gas. Ask your supplier as to the type of wire to go with if you don't know which to chose for your application. Tensile strength and elongation in wire selections also play a big factor into project design and choice of materails, another aspect often overlooked.
However, the choice is ultimately yours. As Rock always says, "be safe". That should be considered foremost in all projects. Know your limitations.
Hobart Expert Rock
11-01-2002, 11:24 AM
TYNEWOOD...........START WITH THE SETTING ON THE DOOR. THESE WILL GET YOU INTO THE BALL PARK....... NEXT PRACTICE ON SOME SCRAP FIRST TO GET THE FEEL OF THE MACHINE. THEN ADJUST TO YOUR SPEED AND COMFORT LEVEL.........
NOW YOUR READY TO START ON YOUR PROJECT......TRY 20 TO 30 PSI ON THE GAUGE............ADJUST TO THE SETTING BY WATCHING THE WELD......NEED LESS TURN IT DOWN I DOUBT YOU GET BELOW 15 PSI BUT YOU MIGHT. DEPENDS ON YOUR SKILL LEVEL.
NOW SET BACK AND SEE WHAT EVERYONE ELSE HAS TO SAY. YOUR ABOUT TO HAVE SOME FUN...........ENJOY.....WHAT IS YOUR FIRST PROJECT ANYWAY...............BE SAFE..................ROCK