Help with aluminum outside corner...

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I'm working on a battery box for my latest motorcycle project using 1/16th aluminum. I'm using a miller diversion 180 with 1/16 tungsten and argon set at 15. I've been using 3/32 aluminum filler rod, but I think I need to go get some 1/16 rod. I'm prepping the aluminum with a ss brush and acetone. The workpieces are clamped with no gap and edges together as to form a "v" to the outside corner.  My main problem is with tacking and starting the weld. I'm struggling to get the two sections to melt together. When I bring the arc from one side to the other the puddles will not cometogether. Each section just melts away forming a bigger and bigger gap. I've managed to complete a few outside corners, but with little consistency starting and tacking. Any advise?Thanks in advance.
Reply:What amperage? What size cup? How much stickout do you have from the cup? That 3/32" filler is going to be a bit harder to use than 1/16" on thin aluminum. For outside corners a short stickout is usually best because the corner splits the shielding gas.Airco Ac/Dc 300 HeliwelderMillerMatic 200 (stolen)Miller Maxstar 150STLMiller AEAD200LE (welding and generating power) Hobart MIG
Reply:Get rid of the sharp corners and file them back to expose 1/16 on each side, and give it a go again. You may wanna drop down to a 1/16 filler as well. I hate being bi-polar it's awsomeMy Heroes Have Always Been Cowboys
Reply:Thanks for the advise guys. I'm using a #7 cup with about 1/8" stick out. I had a feeling the filler was too big, I'll pick up some 1/16 tomorrow.   I'll try filing back the edges, it makes sense. I never thought of that...
Reply:I cannot speak to the TIG part of it, since I mainly use OA welding, but when you have problems with attaching Aluminum...- Which alloy is your box?  Which alloy is your filler material?  It make a difference.  If your local place is selling you a 50xx sheet and you are using 1100 filler, that probably isn't going to work.  (IN the AO world, if you were using 50xx alloy, you would want to use an acid flux, to overcome the anti-corrosive materials in the alloy.  I have no idea what that means to you in the TIG world).- With aluminum, your parts have to TOUCH, or you will just blow a hole in it.  Whether you get the pieces touching by tacking on one corner and pushing them together as you go, or heating areas with the torch to make the edges touch before tacking, the aluminum edges MUST touch in butt welding.- Not flowing together can be a flux issue (I don't know if you use flux while TIGging, but we do with OA and it helps keep the metals super clean and ready to bond to each other.)- For OA, I'd be using a tip a little thinner than the material, using about a 2-3X the material cone (a LOT of heat), with a feather of about 1/2 cone.  I'd be using a filler 1/2 to 1X the thickness of the material.- you COULD consider another joint design on that battery box (make it a flange weld, instead of a butt weld), then you don't have to worry about which filler to use, since the flange becomes the filler.) This technique is a bit easier to master, over butt welding.- Once you get your weld puddle, you have to BOOGIE...there is a much narrower temperature range between 'hot enough to melt' and 'blowing through' in aluminum than steel...not to mention you don't have that beautiful, orange puddle to say, "I'm ready!."  Once you see the surface change and drop a little, you gotta move it.- Another note...consider switching to 91% Isopropyl Alcohol for cleaning metal before welding.  It is just as effective as acetone, not harmful to you, environmentally friendly, and dirt cheap at your local pharmacy.- Don't feel too bad...butt welding very thin aluminum is just about one of the hardest techniques for welding.  Consider changing your joint design to make it a little easier on you.  You can flange weld (with a flange on the ouside) or butt weld a flanged joint.  I have even been experimenting with flange welding with the flange on the INSIDE of the corner.  Once I get done building my big Christmas present, I can get back to those experiments.KevLast edited by Machine_Punk; 12-08-2013 at 09:27 PM.Kevin / Machine_Punk from The Aerodrome Studio - Lincoln PowerMIG 210 MP - Meco N Midget w/custom welding station - Vintage Victor 100Current Projects: The Aerodrome Studio
Reply:As Kev said, your edges must touch. And if you are autogenously tacking you have to hit it hard and tight before it melts away. Get your tungsten right against the metal without touching it. Then jam hard on the pedal.If you have any mig wire, you can cut off a piece and to a layrod tack. Tuck the rod under the tungsten and pop the arc hard and presto tacko.3/32 diameter filler. You are a braver man than I.Weld like a "WELDOR", not a wel-"DERR" MillerDynasty700DX,Dynasty350DX4ea,Dynasty200DX,Li  ncolnSW200-2ea.,MillerMatic350P,MillerMatic200w/spoolgun,MKCobraMig260,Lincoln SP-170T,PlasmaCam/Hypertherm1250,HFProTig2ea,MigMax1ea.
Reply:Try a high current blast of power, and a 1/4" movement of the torch along the seam if it doesn't fuse right away. Edges must be touching. If not you can try blasting on the tip of the filler which you have setting across the gap. It's counter intuitive, but you can get yourself into more problems tacking aluminum when you don't manhandle it. If it doesn't fuse in the first second, it's not going to.Welding/Fab Pics: www.UtahWeld.com
Reply:I did a storage box out of 1/16" without a foot control. I had the inside corners touching leaving the nice open v to fill.I clamped a 1"x1" 1/8" steel angle iron as a backer and welded it out that way (cheating )Since I had no foot control, tacks were at full amps. Maybe you are trying to tack with too low of amps?It was not a fun way to do it, but it worked fine. Many tacks are needed along the edge to keep it from warping.Thank goodness I have a foot control now Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Thanks to everyone who posted. I picked up some 1/16 rods, and had a few minutes today to experiment. I found that for tacking the quick pulse at 130+ amps worked really well so long at there is zero gap. I also tried the quick high heat pulse on the tip of the filler rod worked well for tacking when there is a slight gap.   As far a running a bead the 1/16 rods work much better. I'll have some weld pics up tomorrow. Thanks!
Reply:Hello ncoloqerojr, one other little tidbit for your consideration. Try using a piece of stainless steel angle iron or square/rectangular bar stock as a backing to the weld joint. This will allow for a greater degree of control of the weld pool and provide support for the weld joint to help with the prevention of fall-out of the weld bead. Good luck on your project. Best regards, Allanaevald
Reply:Thanks again!
Reply:Do you have a foot control?When I wasn't using one, I wasn't applying enough heat at the start.With no foot control you either start well, and get too hot (or travel crazy fast), or too cool, and all the aluminum melts at once because it all heats up and falls away. I found this very frustrating.Other materials I had welded (stainless etc) are very forgiving in this regard. Not aluminum.Chay
Reply:Corners are fun once you get the hang of it... Real easy, sounds like you just needed to get some rod in there sooner to get the puddle going.HTP Invertig 201Lincoln Idealarc SP250Miller 180 AC StickBy farmall:They should have held the seagull closer to the work, squeezing evenly for best deposition.
Reply:For tiny stuff I like to start with a sharp tungsten (what ever type for tacking anything will work)  The inverter can be set to do just about any joint so using a transformer takes a bit more concentration. The sharp tungsten will hold the heat to a small area and help get your tacks.....As mentioned hitting it hard at first is the way to go but that takes practice unless you plan on sanding the corners.......If you  want to keep everything tight and not sand the corners you can sneak up on the tack with low amps and small filler.  Using thin material with aluminum for boxes can be challenging so practice on some scrap first.......  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock