Butt Welding Sheet Metal

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Hi everyone, I decided to do some modifications to my motorcycle so I thought I'd learn to weld 20 gauge sheet metal.  I have a clark 130E using 75/25 0.023 wire at power level 1-max with wire speed 2.5 (as per mfg).  On some scrap 20 gauge, I've been able to make some really good beads with good penetration (i still blow some holes but not too often).  My issue is that when I go to butt weld I can tack the sheet metal together (no real penetration but joined on the top) but when I start to put down a bead the sheet metal just melts away from each edge....  Any help you can give is much appreciated.Zonker
Reply:Try a piece of flatten copper pipe fitting for a backer, to soak up some of the extra heat...and your weld doesn't stick to it. (I put spatter dip on mine when I use it)"Good Enough Never Is"MIller AC/DC  ThunderboltHobart HH180, 125EZRiland Cut 40 Plasma oxy/act  outfitTons of "stuff", all treasures to me!
Reply:thx for the idea... here are some examples of what i'm talking about. upper left, good bead with good penetration... but the butt weld looks really bad.. Attached Images
Reply:You can try to turn down the voltage a little.  The copper backing is a BIG help.  Something else you can do is weld the piece in a series of tacks or small welds placed along the joint until it is welded completely.
Reply:You can try changing the position so you're welding it vertical down instead of flat.   Vert down puts less heat into the metal and the weld falls onto itself instead of trying to burn through.Also you can change the joint to a lap joint instead of a butt.  Laps are easier to weld without burning through.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:Yup  thin stuff is about the worst lots of grinding after  tac tac tac  let it cool so you don't warp it ..... and if that is not a fire brick it may explode when heated    good luckLincoln 225 Tombstone,Miller Big 20,Hobart 180,150' Argon,A/D hobart hood 22 Ton Log splitter,79 F350 dump eats 4.75 TONS and still turns cutters,grinders,And a  Hypertherm POWERMAX 30
Reply:Can you turn the heat down any?  Your just running to hot.  What does power level 1-max mean?Have we all gone mad?
Reply:the clark 130 has 4 heat settings and then a min/max.. so the order goes 1-min, 1-max, 2-min, 2-max... etc...  the 1-max is the second power setting.  i have tried 1-min but i don't seem to get any penetration.  from everything i've read on here, it seems that when you can run a good bead down the metal with good penetration that is the level you should use.  is that incorrect?  i'll try turning down the power.thx for all the help.Zonker
Reply:Like Weldrwomn and Tony D said, you don't get to run beads. When edge welding 20 ga, it's bzzzt.....bzzzt....bzzzt....bzzzt. And don't run them in a row. Jump around the perimeter of the panel with each tack. As said, a backing is helpful.9-11-2001......We Will Never ForgetRetired desk jockey. Hobby weldor with a little training. Craftsman O/A---Flat, Vert, Ovhd, Horz. Miller Syncrowave 250
Reply:1-min & slow wire speed. Let the puddle form, then move with it.  Thin stuff is a biotch to glue together.  Or most auto body welders use the tac - tac - tac - tac method.  Keep your tac's 6 inches apart at least & alternate the ends of the panel, tacking between the tack welds.MarkI haven't always been a nurse........Craftsman 12"x36" LatheEnco G-30B MillHobart Handler 175Lincoln WeldandPower 225 AC/DC G-7 CV/CCAdd a Foot Pedal to a Harbor Freight Chicago Electric 165A DC TIG PapaLion's Gate Build