MM 180 and aluminum settings

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Below is a query I posted on the Miller forum, but I think it is appropriate here as well. I am looking for a few basic starting settings for  welding aluminum on a very occasional basis. I am building a folding work cart to carry on-site for my job (I 'm actually into glass!) so I can handle not too pretty, but sturdy is an asset. Any beginner hints are much appreciated!   Hi all - a rank newbie here with a new MM180 to play with. A short course at local college hooked me, mostly for fun and to work on my '68 Fargo van. My first project though involves 1"x1"x1/8" aluminum tubing, and no I won't be doing much aluminum so I won't be purchasing the spoolgun and controller. A search on these threads suggests it can be done with some difficulty. I have clean metal, argon, it feeds fine thru the new steel liner, but finding the right volt/wire speed settings is a crap shoot. The dials don't relate to actual volts or inches per minute, and 50 (out of 100) can't mean 90 amps (out of a max. of 180) since it has a minimum of 30 amps. I'm getting lots of metal transfer but poor adhesion when tested. Any starting suggestions? I'm starting high (80) for spray transfer but something isn't right. Also, with 25 cfm argon should it still come out looking black and sooty before brushing off? More gas ? Can't wait to get into steel again! Thanks for any replies.
Reply:I think you need more gas. Try 35 cfh.  Spraying aluminum makes a lot of heat.   I think you will burn right through if you try to spray that tubing.  Forehand right? (gun angled slightly towards finish line)Only my opinionDavid Weldaholic
Reply:Welding AL with a Mig you'll want to start by doubling the wire speed verses what you would have it for steel.  Pure argon at 15-20 CFH and push the gun don't pull keeping the tip about 3/4" away from the material. Fine tune from there.
Reply:Thanks for the hints David. I'll try more gas, but can you give too much and cause air to be sucked into the work? As for spray,  my limited understanding is thats whats needed for Alu.?
Reply:Hey tmercer,I do a lot of aluminum MIG in the .080-.250" thickness ranges. Since your welder is incremented in 10's(0-100), and also your wire speed, for the thickness you are trying to do, set your heat at 60 and wire feed at 80 to start. Always set up your machine with scrap....plenty of scrap. Your argon CFH should be in the 23-28CFH range. You didn't mention the grade or thickness of wire you are using, so suggestions may be futile without specific parameters. The info I am furnishing is for my use of 5356 @ .035dia.. I found more favor with 5356 than 4043 in the applications I do, and also being a little stiffer, feeds much nicer. I do use both grades for the intended material though. One thing that may really help with reducing burnback and birdnesting, is to simply loosen your wire feed tensioner spring so there is just enough pressure to feed the wire and if burnback stops wire feed, the drive roll will just spin on the wire and not cause the birdnesting on the roller. On my MIG welders, setting 60 is about 100A and 80 wire feed is about 550 ipm. I run my welders at settings 60 heat and 83 wire speed for that thickness. Keep your torch angle at approx. 80 degrees, no less, and your wire stickout at 1/2-5/8"...no longer than that. You gotta move fast with alum., and also, don't change your movement speed once your puddle gets the good flow starting. Also, the soot is not a problem as it brushes right off and doesn't affect the weld. The primary importance of any aluminum welding is the cleanliness of the alum.. A good wire brushing with a SS brush and wipe with acetone will render the alum. chemically clean for a good weld. Alum. is very finicky with cleanliness. Gotta be super clean. The thing you will notice when you are getting a good weld will be the sound.... when the settings are peak, the welding sounds like a smooth hummm....not the "bacon" crackle of steel wire. You gotta do some serious practicing though, but once you get the "hang" of it, you will really like doing aluminum. Keep at it...let us know how you progress...Good luck....DennyComplete Welding/Machine/Fab. ShopMobile UnitFinally retired*Moderator*"A man's word is his honor...without honor there is nothing.""Words are like bullets.... Once they leave your muzzle, you cannot get them back."
Reply:Here is a link http://www.millerwelds.com/education...calculator.phpIt has spray settings for 1/8"DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Thank you David, Tsor, and Yorkiepap for your responses and insights. I am sure I will be a bit of a bug for a while until I learn more from the pros. My machine (MM180) has two dials: Volts, 0-10, and Wire speed, 0-100. I understand that wire speed is linked to Amps, and on my machine this 0-100 dial relates somehow to the 30-180 amps/90-700 inches per minute it is rated for. On the Miller welding calculator page (thanks David) it suggests, for .035 wire, an amperage of 110-130, and a wire feed of 350-400 ipm, with a voltage of 21/22v. Since I can't set the amperage directly, if I set the feed dial to 80 as Yorkiepap suggests, will this be in the amp/ipm range I need? And what would you suggest for a volt setting on my 0-10 dial for a voltage of about 22 volts? The machine is rated for up to 31V, but I think it starts at a bit more than 10V. Is there a standard number of amps for a given inches per minute for these smaller 230V machines? So many questions, I hope I'm not too much of a time sink! Thanks again for the replies, tmercer.
Reply:For welding 1/8" AL with .035 wire, try setting your wire speed to 70 and voltage between 6-7I'm basing this on what I set mine at to weld 1/8" al.  I have a DVI which is rated about the same as a MM180.
Reply:Amps are a direct effect of wire speed.  1 amp for .001" of plate.  1/8 is .125 so about 125 amps.  .045 wire is 1 amp per inch per minute.  SO 200 ipm would be 200 amps.  With .036 wire its wire speed times 1.6 = amps.  This is for one pass flat.  The way I  was taught is pick your amps, set that first (wire speed) then adjust volts to get a smooooth arc.  You will be surprised what 1/2 volt can do to your bead profile and penatration.My welders now all have volts and Ipm on the dials.  Makes my life easier.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:David,My DVI is capable of 600ipm! So, with .035 wire it will put out 960amps!!!Am I missing something here?  It's only rated for 175amps. I'm not understanding your amp calcuulations.
Reply:this is for calculating What you need.  Maybe 600 ipm of .023 ?  Lets do it again, 1/8' = .125".  125 amps times the multiplier of 1.6 for .035 wire = 200 ipm of .035 wire.  These calculations are more for steel.   Once you exceed the amp capacity of your machine, it will just stub and the voltage will drop.  This is only a guide.  SO for steel wire, you can go about 280 Ipm.  I have a wirematic 250 and I don't know how high the wire speed goes, but the fastest recomended for .035 is 360 and 20 or 21 volts.  This is for 5/16" plate.  360 ipm divided by 1.5 = 225 (amps).  SO I might be able to bump it up to 400 (250 amps).Real world weldin.  When I grow up I want to be a tig weldor.
Reply:The wire speed on my machine is 50-600ipm and the dial reads from 10-100. No way to tell if the speed adjusts linear or exponential without a meter. Also the voltage is only a 6 tap, also no way to tell the value without a meter. Your calculations seem to make sense, but I guess there's no way to apply it to my machine.Sorry for the hijack!Any progress on the AL welding??
Reply:Thank you all for your replies and information. I will be doing some more this Friday and will keep you posted. On my machine I think I will be going for a wire dial setting of 80 and a voltage dial setting of perhaps 6.5 and hope this translates into 125 amps or so and around 21 volts. I'm using .o35 5356 wire and at least 25 cfm argon. Oh yeah, and clean! Thanks again  Tom    PS - why aren't volts/amps/wire speed noted on the dials?
Reply:Get rid of the steel liner.I changed from steel to synthetic and it made a world of difference. The steel embeds into the aluminum.
Reply:Originally Posted by tmercer    PS - why aren't volts/amps/wire speed noted on the dials?
Reply:The Miller folks replied to this question, use a meter! Seems odd not to have such info not on the dial, when their site suggests specific amps and volts, not numbers on the machine. Oh well. I have managed to get a couple good test welds by increasing the voltage up to 7.5, and the feed up around 80. Really clean is key (I'm using the cleaning acid now too) and not too close or you end up buying tips in bulk at this amperage. Maybe the liner is contaminating too but it is brand new, no steel and just under a pound of Al. wire thru it so far. Feed is OK as long as I don't melt the wire to the tip. Hints on starting a bit ahead and coming back to the beginning to preheat, and filling the puddle at the end all should help, but the 1"X1" tubing I'm using only allows for a short weld anyway. Good and solid is more important for now than good looking but I'm aiming for both.Thank you all for the help, tomorrow is production day with any luck. Happy Easter!tmercer