Thin Aluminum questions
Tue, 31 Aug 2021 14:23:27 GMT
I was asked to do a project which requires butt welding small panels of 1100 aluminum (.050"). I have 1/16" rods (also 1100 Al) and am using a Lincoln precision Tig 225 with argon. I played around with the amperage from 80 up to 130. First, even with a zero gap butt, trying to tack the edges is very difficult - they just want to pull away from each other regardless if I hit it with a short burst of higher amps or slowly with lower amps. Second, is there any way to minimize the weld through? I'm thinking not just due to the thickness of the sheet and the rod diameter I'm working with but if anyone has suggestions, I'd love to hear them
Reply:Forgot - 2% thoriated tungsten, tried 3/32 and 1/16, both started with pointed tips... Balled up after use. Balance was on auto, biased towards cleaning provided a little better results.. Maybe
Reply:From what you are explainining, I would choose the 3/32" tungsten. Red is what I use on my 200 and it works fine. I would take it off of auto balance and run it at 75%. You have to dance between melting the tungsten or the puddle. I would also choose 3/32" filler to chill the puddle and run the weld cold.As far as the edges melting when tacking, I feel your pain. I personally would lay the rod on the seam and strike an arc on the rod. I will melt to a little ball that will then wet the seam together. The project sounds like a pain. Good Luck.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:Are you cleaning the oxides off your material before you begin welding? If not, give that a try, should help your edges from pulling away from each other
Reply:Sometimes with a job like that, I'll strike an arc on the table and approach the ends of the joint gently (low amps) then I'll lay the rod on the spot where I want the tack to be, as shovelon suggests. When I get to that spot with the torch, I'll increase the amperage until the rod melts . Then, decay out...For the intermediate tacks, I'll pretty much do the same thing, except that I don't sneak up on them. I'll lay the rod on the spot, then gently strike an arc on that spot, then increase the amps until a small droplet of filler is left behind, then watch it melt in.Clamping that whole joint down on each side is important. That thin stuff likes to warp!I also agree with 3/32" 2% red tungsten, and 3/32" filler rod.As far as minimizing melt through, that's just a finesse thing...lowering the amps as you go due to the base metal getting hot. I think that increasing the filler rod dia. to 3/32" will help with that, also.Rich
Reply:My pt 225 welds pop cans. .050 is easy. 1/16 tungsten maybe 3/32 probably too big and 1/16 rod. I leave my balance pretty high usually around 80% or more I think. It will eat up tungstens if you go much below that. And what I do is just light up really soft so it won't even puddle, then just ease on the peddle and aim the tungsten right in the middle of the joint and get on it harder and puddle it even on both sides no Dicken around and start moving. 1/16 tungsten can handle about 90 to 100 amps on ACLast edited by motolife313; 11-14-2015 at 10:21 AM.
Reply:I sincerely appreciate all the input! I ended up,doing pretty much what everyone else said: turned the balance up, let the arc slowly warm up the area and then move fast. Once I got the base melting, the biggest thing for me seemed to be balancing the torch angle and the filler rod. Still nothing I could do about the melt through - to me, just getting the base metal hot enough to accept the filler caused the weld to sag. I would think an even thicker filler rod would only make it worse? Thanks again
Reply:To keep the edges from running away from each other, bring your tacks in from corners, I start in the center and work out, but never all the way to corner. I use high amps, quick dab. To avoid weld through, I would try pulse, or super fast travel speed. You could also try backing the joint with aluminum or copper.Constant Current Weldor.
Reply:+1 on using copper backing. If you can get it to fit tight to the parts it will suck out the excess heat. Speed is still going to help avoid melt through. I find a pointy 3/32" tung to be more precise than 1/16" with a bigger ball on the end. Low speed pulse: ~1hz might help, but I'd just use the pedal.SqWave 200Millermatic 190Airco 200 ACHypertherm PM45Boice-Crane Band SawVictor O/A
Reply:Originally Posted by shovelonFrom what you are explainining, I would choose the 3/32" tungsten. Red is what I use on my 200 and it works fine. I would take it off of auto balance and run it at 75%. You have to dance between melting the tungsten or the puddle. I would also choose 3/32" filler to chill the puddle and run the weld cold.As far as the edges melting when tacking, I feel your pain. I personally would lay the rod on the seam and strike an arc on the rod. I will melt to a little ball that will then wet the seam together. The project sounds like a pain. Good Luck.
Reply:Originally Posted by soutthpawMelting a ball and washing it in is what I've been trying to do on that thin stainless...
Reply:Originally Posted by soutthpawMelting a ball and washing it in is what I've been trying to do on that thin stainless...
Reply:So you melt the filler before the material "shines"?
Reply:Steffan, hope this weld worked out for you eventually? My take on seeing the first beads was the weld seems out of, or proportionally large for the parent metal? The techniques listed by the replies all apply but concentrating on a smaller overall bead seems (IMO) most important as the first step in view of the pictures shown?The sag/penetration/print through all seem to come from a too large bead? If the bead were about 1.2 to 1.4 times the parent metal thickness that weld would have much less power/wattage/heat and not involve such a wide foot print so the weld would be a small fraction as large as shown. I think the sag is from the weld heat being too much greater than the thin parent metal can conduct away (chill) from the weld zone- solution? make the weld smaller in total volume so it can be welded with less heat input. [Note I TIG weld with a wire feed TIG gun so the filler in my case is 0.023", 0.030" or 0.035" not hand fed larger diameter wire.]One technique (I think I learned it in the 1970's? ) is to take (about) 3" of small copper or SS tubing and grind a cup/cut/recess into one side, clean that cupped opening's edges (about 1"- 1-1/2" long about 1/2 through). Put MIG wire 0.045" wire in the tube and feed with the side of thumb sliding in the cupped opening. This allows feeding tiny filler so the puddle heat is not totally chilled by huge diameter wire. This 'poor-man's' TIG pencil feeder comes in different flavors but allows MIG wire sized filler to be used in hand fed TIG to do smaller welds. The TIG welder that showed me used to cut 2 or 3' pieces of MIG wire and hold one end in the vise and jerk on the other end with vise-grips, seemed to "straighten" or take most of the wire spool's coil out of the wire and the tip end of the feed tube can be crushed nearly closed with pliers to leave a small opening so the filler wire will 'go where you aim it' instead of wandering around to plunge into the tungsten.Just a few more cents of opinion on welding thin aluminum.Cheers,Kevin MorinKenai AK
Reply:Thanks Kevin, I tend to agree: The 1/16" fill rod was/ is overload for the .050" base metal. I got the job done and although it wasn't aesthetically pleasing as I would have liked, the customer was happy. If more of these projects come around I'll break down and get some Al MIG wire - it's the same thing I do for some of the small SS projects I do.
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