new to mig welding aluminum!

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Hello! im new to this forum as well as mig welding aluminum! i have no idea what im doing wrong and i have gone through almost everything.  My welds are penetrating but they are messy and really dirty.   any help would be appreciated! Attached Images
Reply:Hey Kevin,The forum members cannot provide you any help unless you post all the relevant data necessary.1) What is the make/model/output power of you MIG?2) What type/size of wire are you using?3) That looks to be a casting....is it?4) How did you prep the repair? Do a pre-heat?5) What is your experience level MIG welding?6) Did you do any practice on aluminum of the same thickness/type?The pic indicates your MIG either doesn't have enough power; if it does, you didn't have it turned up enough; & the metal looks quite dirty. Aluminum is quite finicky regarding cleanliness.....if it's not chemically clean, it's not gonna weld good. A MIG welder with sufficient power can do superb repairs. I have repaired many aluminum castings with my MIG units without any failures simply because I did the necessary prep & preheat.Ok... your turn. Fill in the blanks & we'll see if your repair can be accomplished without too much re-work. I would offer that your attempts will have to be completely ground out with a carbide cutter/burr, some beveling, & a good scrub with a SS brush & acetone, & a preheat to about 250-300*. It's not hard if you don't make it hard.....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:thankyou for the quick reply!! it looks like i didnt do any of the right things! i did manage to scrub it with a ss brush and clean with acetone. i have a lincoln electric pro mig 140 hd  lincoln .30 wireit is cast getting welded too sheetthe only prep i did was scrub and acetonei have been mig welding for about 3 years now but never attemped aluminum till yesterday. this is my practice/ trial run hah
Reply:The only way I know to weld aluminum with a mig is a spool gun. Doesn't look like you have one?Torchmate 2x2 CNC with Flashcut CNC controlsHypertherm Powermax45 Esab ET220i Razorweld 195 MigRazorweld 200ac/dc TigTormach 770, Tormach xstechRazorweld, Vipercut/Vipermig, SSC Foot Pedal Dealer
Reply:i do not have a spool gun but i got the welder setup perfectly and feeds the wire through quite smooth
Reply:Hey Kevin,Ok....you indicate that your MIG unit feeds the filler wire fine. Now, fill in answers I posted on my first response.....we need information.To Gamble:  Since you indicate "The only way I know to weld aluminum with a mig is with a spoolgun", I would suggest you do some homework. Standard MIG gun/cable assemblies have been used successfully for many years. I have (2) spoolgun/welders(shop/mobile) & an individual MIG unit with a standard cable/gun assembly that I use in the shop for all alum. production welding <.187". Many units(w/10' cable) will not feed the softer 4043 as compared to the stiffer 5356, although wire grade must be considered if the temps of the repaired item will be in excess of 150*. In that instance, 4043 must be used. My individual unit has a nice, short 6' cable & will feed either grade effortlessly. I know several weldors who picked up a spare cable assembly for their MIG units & had the cable shortened specifically for alum. welding.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:you just have to keep the gun as straight as possible with the aluminum rollers and teflon liner.   that said I don't think the OP has a powerful enough welder to weld the stuff in the pic.   remember Aluminum is a giant heat sink and requires at least 25% more current for the same thinckness as steel.  also Aluminum requires 100% Argon shielding gas. if you have a 75/25 argon co2 or any other mix that is used for steel it will NOT work.   so make sure u have the right gas.  a quick check of the Miller calculator has the MIG settings for short circuit 1/4 Al at 140-150,  180-210 for spray transfer with 3/64 wire at 350-375IPM.  it doesn't even list a wire speed for short circuit above 1/8" material . Doing multiple passes ain't going to cut it either because you are just not getting the base metal hot enough to fuse properly.    preheat may help. this may be one of those examples where Rick V's verbose stick welding aluminum threads would apply and work well for a OP who appears to be doing this as a hobby on a limited budget.   If its an intake or exaust manifold which it looks to be it is going to leak unless u get a sound solid weld.  Ricks thread would be a good read for the OP to see at least how current and preheat can drastically effect outcome of Al weldingTiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:Originally Posted by yorkiepapHey Kevin,Ok....you indicate that your MIG unit feeds the filler wire fine. Now, fill in answers I posted on my first response.....we need information.To Gamble:  Since you indicate "The only way I know to weld aluminum with a mig is with a spoolgun", I would suggest you do some homework. Standard MIG gun/cable assemblies have been used successfully for many years. I have (2) spoolgun/welders(shop/mobile) & an individual MIG unit with a standard cable/gun assembly that I use in the shop for all alum. production welding <.187". Many units(w/10' cable) will not feed the softer 4043 as compared to the stiffer 5356, although wire grade must be considered if the temps of the repaired item will be in excess of 150*. In that instance, 4043 must be used. My individual unit has a nice, short 6' cable & will feed either grade effortlessly. I know several weldors who picked up a spare cable assembly for their MIG units & had the cable shortened specifically for alum. welding.Denny
Reply:Might as well stick a needle in your eyeCast AL to Sheet AL with a Lincoln 140Ed Conleyhttp://www.screamingbroccoli.com/MM252MM211 (Sold)Passport Plus & Spool gunLincoln SP135 Plus- (Gone to a good home)Klutch 120v Plasma cutterSO 2020 benderBeer in the fridge
Reply:Originally Posted by broccoli1might as well stick a needle in your eyecast al to sheet al with a lincoln 140
Reply:Originally Posted by Broccoli1Might as well stick a needle in your eyeCast AL to Sheet AL with a Lincoln 140
Reply:Originally Posted by soutthpaw also Aluminum requires 100% Argon shielding gas. if you have a 75/25 argon co2 or any other mix that is used for steel it will NOT work. . g
Reply:Originally Posted by LawsonWeldingLLCNot quite true. You can use any variation of helium and argon for mig welding AL, a helium mix is alot better than pure argon... Helium introduces more heat into your weld and gives the Hydrogen a better chance of escaping. Kaiser Aluminum Welding - the book shows alot of pretty good information on this subject.
Reply:Originally Posted by soutthpawYeah I know about Helium,  which will increase the heat transfer but I was trying to keep it simple.   thats the comeback for guys who say you can only tig Al on AC...Bet he has 75/25 heh.   Either way he is going to need a bigger machine and a lot more practice
Reply:As I am also new to Aluminum welding, I tried to search for threads using mig on Aluminum. The search engine didn't work. just FYI.There are no problems. There are only solutions. It's your duty to determine the right one.Hobart Handler 210Airco 225 Amp MSM Stinger
Reply:http://www.alcotec.com/us/en/solutio...um-Welding.cfmI forgot how to change this.