Straighten 1/4" plate... with stick?!?

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New hobby welder here. Working on a welding table using materials that I have. That includes a 48 x 30 x 1/4" plate that I would like to use for the top. It was bowed by about 3/8" at the highest point. Mostly a smooth camber. I managed to get almost 1/8" out of it by raising it up a couple of inches and parking the car on it for a while. Trying to figure out if I can get the rest of it flat enough to use as a welding table.I don't have much gear, just my 110V, 70A inverter stick welder. I was looking at flame straightening and wondering how I might do something like that using the stick welder to supply the heat, since I don't have an oxy setup. I was thinking of cranking the welder to max, using 3/32 6011 or 6013 and running beads, perpendicular to the bow. I'd start with one bead across the center of the sheet, followed by beads further and further away from the center, as needed. Obviously I'd be welding on the convex side.Am I crazy? Any thoughts on how to make this work? Better ideas?
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Originally Posted by Montrealais

New hobby welder here. Working on a welding table using materials that I have. That includes a 48 x 30 x 1/4" plate that I would like to use for the top. It was bowed by about 3/8" at the highest point. Mostly a smooth camber. I managed to get almost 1/8" out of it by raising it up a couple of inches and parking the car on it for a while. Trying to figure out if I can get the rest of it flat enough to use as a welding table.I don't have much gear, just my 110V, 70A inverter stick welder. I was looking at flame straightening and wondering how I might do something like that using the stick welder to supply the heat, since I don't have an oxy setup. I was thinking of cranking the welder to max, using 3/32 6011 or 6013 and running beads, perpendicular to the bow. I'd start with one bead across the center of the sheet, followed by beads further and further away from the center, as needed. Obviously I'd be welding on the convex side.Am I crazy? Any thoughts on how to make this work? Better ideas?
Reply:What popeye suggested is what I did to my 3/8" top. It had a convex bow in the top. I put two 4" channels under welded on each end to the bottom of the table . Then rigged a chain and bottle jack to push the concave down to the channel and welded the top to the channel with stich welds. Not perfect but good enough for who it's for. I don't build nuclear reactors anyway, LOL!!  If yours is concave on top then weld the channel to the center and then pull the top to the channel with C-clamps.Last edited by mla2ofus; 07-25-2021 at 03:53 PM.Ol' Stonebreaker  "Experience is the name everyone gives to their mistakes"Hobart G-213 portableMiller 175 migMiller thunderbolt ac/dc stick Victor O/A setupMakita chop saw
Reply:Just build a stout frame, turn it U up, then clamp it to the frame, shim as needed, and tack to frame.
Reply:When I made my 1/4" thick welding table, I over-welded it on the bottom to the 1.5" x 1.5" tubing frame, which resulted in the top of the table being convex, like an umbrella.  To flatten / straighten it, I used 1/8" 6011 run HOT to weld two big parabolas -- in kind of an "X" arrangement -- across the top of the table. The shrinkage pulled the warp right out of it. Then I ground off the bead with an angle grinder.Last edited by Kelvin; 07-25-2021 at 06:05 PM.
Reply:As mentioned. Make up the frame the top will be tacked to. Clamp top to frame and check for flatness. If it doesn't meet your standards, you can tack say 1/2" nuts to the plate high spot or spots. Then add steel spanning where nuts are with hole add nut locations. Cut 1/2 " all thread rod to go into nuts and extended below added steel. Add washer and nut to rod and tighten down. Leave as is with rods and nuts and add tacks to secure. You could tack steel to underside of top to steel below if you prefer that. Sent from my iPhone using Tapatalk
Reply:This 1/2” is dead flat.  Strong square frame and very careful tacking in strategic locations all the while checking flatness with straight edge.


Reply:Make a frame and it shouldn't be too hard to pull the plate down flat. When putting checker plate on large skids we used to use a bar with piece of 3/8" or 1/2" flat bar on the end. Tack the flat bar on the back corner to the checker plate with the other corner on the flange of the I beam or angle cross member. Have a helper push the bar to suck the checker plate up and tack the checker plate to frame. You could make a couple screw dogs too.https://www.aba-machine.com/pipe-han...s/welding-dogs
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