How Would You Weld This? .019 aluminum corners

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How would you weld up these corners?  Doesn't have to be real pretty or watertight or anything, but a little strength and few holes would be nice   Inside or outside, doesn't matter to me.    Material is .019 aluminum, not sure what alloy.  None of the calculators I have, or can find online, go anywhere near this thin.  I have .040 ceriated, 1/16 ceriated, and 1/16 lanthanated tungstens.  I have 1/16, 3/32 and 1/8 4043 filler.  I have various standard cups #5 and up.  Oh yeah, I have a Sync 180 that'll go down to 10 amps.  I have a 90* clamp to tighten-up the gap, as well.   Full disclosure:  I realize I'm not good enough to pull this off yet, but I do have a stack of scrap to practice on.  Maybe enough to get to the point where I can stick these corners together, if I don't waste too much wandering in the woods.   Thanks in advance.__David Hillman
Reply:I'm sure several folks may explain how you might tig it.Me, I'd braze it:a) High temp: propylene torch, 4047 rod and aluminum flux (Harris Al-Braze 1070 or ESAB-Allstate BRAZO 31) or you could go much faster and with less risk of melting any of the parent metal withb) Low temp braze: propane torch and zinc-based brazing rod such as Hobart Aluminum Brazing Rod - available at TSC stores.Rick V 1 Airco Heliwelder 3A/DDR3 CTC 70/90 amp Stick/Tig Inverters in Parallel1 Lincoln MIG PAK 151 Oxy-Acet
Reply:It looks thicker than .019.
Reply:Originally Posted by jsmarineIt looks thicker than .019.
Reply:Originally Posted by David HillmanMust be an optical illusion.  It's .019" to my caliper.
Reply:Zero your calipers and measure again.But anyway cut a length of angle iron(steel) the height of the lip, and 2 steel plates same length and clamp to restrain the corner. Once fit up and straight, tack and weld your heart out. The inside will take the shape of the angle corner. You could grind a slight radius on the angle iron so the penetration will achieve that profile if you want. Have fun.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:Boy, you guys are a tough crowd.  I expected a lot of "Go practice on thick steel coupons for a few miles and come back when they're perfect" comments, but not this.    Okay, I replaced the battery in my calipers just for kicks, and then zeroed them out.  The sheet is still .019".  I also checked the calipers against my sheet metal gauge, and they seem pretty close.   I hope that suffices.  If not, let's say "Hypothetically, if I had a sheet of .019 aluminum bent into a box, how would you weld the corners?"    Brazing is an interesting idea.  Never tried it, but I do also have a couple torches ( propane, butane, no O/A ).__David Hillman
Reply:shovelon called it on the procedure.  That's a good way if you don't have the experience to just weld it un backed. I'd use the 3/32 filler to help chill the puddle but you could do it with 1/16 if you can keep the amps low enough.Two turn tables and a microphone.
Reply:Originally Posted by David Hillman... Brazing is an interesting idea.  Never tried it, but I do also have a couple torches ( propane, butane, no O/A ).
Reply:I use this stuff ALL the time! works great.ALL-STATE 55 RUBBON (by ESAB)Solder for joining and build-up of aluminum at low temperatures without flux. (No. 53 flux will improve flow) Also for pot metal and zinc dye casts. At the right temperature, forcefully rub Rubbon 55 into the base metal or joint. Deposits that have high strength and long service without galvanic action between base metal Working Temperature 705-720 °F This alloy is especially used by aluminum window manufacturers to solder mitered joints without the use of flux. Ideal for sealing holes in aluminum boats, leaders, gutters, siding, and castings such as outboard motor/chainsaw/motorcycle castings. Unexcelled for high strength and long service without the problem of galvanic action between base metal and solder.ProcedureAluminum surfaces to be soldered must be clean and free of all dirt, grease, and oxides. Sections heavier than 1/8" (3.2mm) should be beveled 75 to 90 degrees. Jigs and clamps will keep parts in alignment. Use a carburizing flame to heat base metal sufficiently to melt the rod when rubbed on the surface. The rubbing action is required to give a good bond. Do not apply flame to the alloy but allow the heat from the base metal to melt the solder. All-State No. 55 Rubbon is made stiff enough to break through the normal oxides found on clean aluminum. Tinning action may be improved by wire brushing through the molten solder.Syncrowave 350 LX TIGRunnerThermal Arc Power Wave 185 TSWXMT 304/12VSESAB Powercut 1500MultiMaster 260MM 200
Reply:+1 on the clamp a piece of angle to the inside of the corner (Copper would be better if you've got any to hand)If you've not got much experience welding Ally, start from the outside (top) edge and weld towards the base so as not to blow an ugly chunk out of it when you get to the end of your weld.Also, try to position the tray so that you are welding straight down onto the corner joint (like this ^), it'll be easier and you'll get a neater job.
Reply:In the future you might also think a bit in advance about joint design. It probably wouldn't have been too hard to have bent the sides over 90 so you had the one side lap the 2nd. then you could have uad 2x the thickness for doing lap welds or soldered easier. Super thin edge joints don't braze well unless you get a decent fillet laid up. My biggest concern with brazing and that thin material will be warpage since alum conducts heat so well. Keeping everything flat may be a PITA.You could always reinforce the corners with some angle and just weld or braze it in place permanently. 1/2" x 1/2" would work. Then just wash the bead from the heavy material corner over onto the sheet..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:How would I do that?I would get a piece of FLAT and TRUE stainless angle and clamp it inside the corners and just do it.40 amps max and footpedal in use..It's not so difficult....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:I was thinking the same thing.  Back it up with some copper or use flux to slow the heat down.  I may have designed that joint differently though.  By the way, I have that same caliper and I really like the fractional measurements.
Reply:Originally Posted by zapsterHow would I do that?I would get a piece of FLAT and TRUE stainless angle and clamp it inside the corners and just do it.40 amps max and footpedal in use..It's not so difficult....zap!
Reply:I agree with DSW, I have made a lot of .019 welds with aluminum (also called coil stock and thick roof flashing for people who don't know) and I always put a 90* bend on it. That way you have a nice joint and a place to clamp to.Edit: you can always make some 1/2" x 1/2" x length angle out of the .019 and weld it up. it won't be as pretty but it will do the job.
Reply:Originally Posted by Baila La Pinza+1 on the clamp a piece of angle to the inside of the corner (Copper would be better if you've got any to hand)
Reply:Originally Posted by DSWIn the future you might also think a bit in advance about joint design. It probably wouldn't have been too hard to have bent the sides over 90 so you had the one side lap the 2nd. then you could have uad 2x the thickness for doing lap welds or soldered easier. Super thin edge joints don't braze well unless you get a decent fillet laid up. My biggest concern with brazing and that thin material will be warpage since alum conducts heat so well. Keeping everything flat may be a PITA.You could always reinforce the corners with some angle and just weld or braze it in place permanently. 1/2" x 1/2" would work. Then just wash the bead from the heavy material corner over onto the sheet.
Reply:Take it for what its worth since I'm a stick welder and not a tigger. I was practicing on some may 20 ga ss since a friend got me a side job repairing a sink at a restaurant and couldn't turn away the money. I could tack it together my practice pieces but when welding the edge would burn away, until I lowered my gas down between 5 and 10 cfh.
Reply:Decided to make my fireworks in the garage, instead of going to watch them tonight.   Tried brazing with my blue wrench, first on this scrap piece.   That wasn't very hard, even though I ignored a lot of the advice above   I just threw it on my table, with a 90* clamp, and went at it from the outside.  I didn't realize how big that blob on the bottom was until after I stopped.   Emboldened by that, I tried the same thing on the real piece.  That didn't work as well, although I think it could've with a more experienced operator.  It's solidly-joined, but I got a lot of blobs.  Definitely not pretty.   So then I got semi-serious.  I set up the following mess...Last edited by David Hillman; 07-04-2011 at 10:17 PM.__David Hillman
Reply:That's a piece of heavy angle, supported by a couple 45* magnets, with the piece resting it in, held still by two more magnets inside.  There's my 90* clamp on the corner, plus a small piece of aluminum angle clamped on the outside, to keep the gap minimal.   And this time, I went at it from the inside.  This would've worked great, I think, but the little piece of brazing rod I was down to got too hot to handle, so I kind of rushed the actual brazing.  By this time, my little non-welding 90* clamp was also getting too hot, so I called it a night.   I may yet try tigging another corner as suggested, if for no other reason than I can certainly use the practice.__David Hillman
Reply:Oh yeah, money shot...   ( Good thing I don't hope to get paid for this  )__David Hillman