Welding sheet metal to square tube?

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Hello everyone,I've built a door for a security storeroom from two-inch square, .083 steel, and I need to perimeter-weld a 16-gauge steel skin to it. I've been doing okay welding similar thickness metals together, but I'm still unclear on how to achieve a proper bead when different thicknesses are involved. How do I ensure adequate penetration on the .083 tube without burning through the sheet steel? I'm using a Miller 180 with .030 flux-core wire.Thanks for any advice!Jonathan
Reply:Set up welder to the thickest metal (your tube), bias concentrate bead mostly on the tube and only weave a little on the sheet. 0.023 solid core with 75/25 gas is less agressive but dont forget to change the polarity. Go to the smallest dia flux core wire if thats your only option. Short stiches will help to reduce heat input and therefore the warpage on the sheet.Hypertherm45, SP100 on gas, 175 AC/DC Sq Wave, 225/125 AC/DC, 7" x 12" Band, Central 16" - 16 speed Drill, 3HP 20Gal Air, Dayton 9" disk - 6 x 48 Belt, Sears 8" Pedistal, Victor O/A Torch, 150amp service to the 40x64 Pole Barn- Priceless
Reply:Can you switch your machine over to short arc?   Solid wire and 75/25  Flux tends to run too hot for thin metal.   It can be done but if your not familiar with the technique then you'll be patching holes.  On the seams your talking about you could tack it all along the edge turn the piece vertical and run downhand once you got your machine set.From my experience.  I started off welding heavy 2" steel with dual shield and spray arc.  Then went to working in a shop that only did sheet metal up to 3/8"  it took a little practice but i got really good at short arc and the welds look soo much nicer.“I'm going to do the thing that God put Galen Beasley on this Earth to do:Have Salon quality hair and weld.Nothing like a good cup of coffee and the smell of 6010 burning in the morning. 971-204-3444 cell API ASME Structural NDT and Repair
Reply:I forgot on the downhand weld on sheetmetal you'll want to point your gun up as you drag down the seam  The reason is you can travel much faster and reduce the heat preventing burn through.“I'm going to do the thing that God put Galen Beasley on this Earth to do:Have Salon quality hair and weld.Nothing like a good cup of coffee and the smell of 6010 burning in the morning. 971-204-3444 cell API ASME Structural NDT and Repair
Reply:The material thicknesses are close enough that I doubt you will see any issue, I would just weld as normal.Have we all gone mad?
Reply:Thank you, all. I don't have a gas bottle yet, so must use flux-core. But the advice here definitely makes sense. I have a scrap piece to try first, so I'll report back  . . .
Reply:Originally Posted by sn0border88The material thicknesses are close enough that I doubt you will see any issue, I would just weld as normal.
Reply:Finished. I didn't seem to have too much trouble once I got the voltage and wire speed dialed in. With a little grinding it looks more than fine for a storeroom door.Thanks very much for the advice.
Reply:nice looks good   did you skin both sides or just the outside?“I'm going to do the thing that God put Galen Beasley on this Earth to do:Have Salon quality hair and weld.Nothing like a good cup of coffee and the smell of 6010 burning in the morning. 971-204-3444 cell API ASME Structural NDT and Repair
Reply:Just the outside to start, and to get it weatherproof. I'll probably use 18-gauge on the inside.