Keeping It Square

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I need to weld 3" square tubing in the shape of a "T".  How do I keep it straight and square when I weld it? Usually it wants to pull when welded. I am using a wire feed process "Millermatic 175".
Reply:If you have access to a steel table with some kind of a backstop, no prob. You can preload/clamp to backstop, tack it to table, weld one side, and then let it cool all the way (grabbable) before undoing it from table and doing the same to the other side.Or you can tack a piece of scrap as a brace or a kicker on each side of the 't', weld, then let cool and remove kickers. Have fun!
Reply:I have a welding table that I can tack some kickers onto.  Thanks
Reply:Originally Posted by jcaro10894I have a welding table that I can tack some kickers onto.  Thanks
Reply:Would it be better to clamp it against a kicker and tack it onto the table?
Reply:If you preload the 't' or break its back by inserting a shim @ the center of the 't' before you clamp it to the backstop you can pretty much kill the pull. How much shim to use varies with the job and material but usually an 1/8 inch rod stub or something like that will work
Reply:Originally Posted by TEKIf you preload the 't' or break its back by inserting a shim @ the center of the 't' before you clamp it to the backstop you can pretty much kill the pull. How much shim to use varies with the job and material but usually an 1/8 inch rod stub or something like that will work
Reply:Originally Posted by TEKIf you preload the 't' or break its back by inserting a shim @ the center of the 't' before you clamp it to the backstop you can pretty much kill the pull. How much shim to use varies with the job and material but usually an 1/8 inch rod stub or something like that will work
Reply:Spider, if you weld 3'' tubing in a 't' shape ,and don't restrain it in some way, then the ends of the 't' will droop, or arch. To counter this you can pre-bend it the oppisite direction, or "up", by breaking it's back before you weld. That way, when you un-clamp it,it'll be straight.If the piece is laying flat on the table with the top of the 't' up against the backstop you can put a shim of just 'bout anything in the center of the 't'before you clamp the ends of the top to the backstop.It will be hard to clamp because you will be bending the 't' opposite the direction that the weld will want to pull it..  Sometimes I cant explain things very well, but I hope this helps
Reply:Keep in mind what's happening.  When you heat (weld) the metal it expands.  Then when it cools it contracts.  Your distortion comes from the contraction process.You can correct the distortion by mirroring what's happened on the opposite side of the weld.  Take your torch and heat the tubing opposite of the weld.  Let it cool.  Your weld distortion will be minimized.If you don't have a torch you can do the same thing by welding and then grinding.  But it's a lot more trouble and harder to do accurately.The secret is to duplicate the heat application as best you can.life is good
Reply:thanks guys
Reply:Originally Posted by wroughtn_harvKeep in mind what's happening.  When you heat (weld) the metal it expands.  Then when it cools it contracts.  Your distortion comes from the contraction process.You can correct the distortion by mirroring what's happened on the opposite side of the weld.  Take your torch and heat the tubing opposite of the weld.  Let it cool.  Your weld distortion will be minimized.If you don't have a torch you can do the same thing by welding and then grinding.  But it's a lot more trouble and harder to do accurately.The secret is to duplicate the heat application as best you can.
Reply:Originally Posted by KELLYBut what if the meterial was bismuth? your weld would contract instead of expand when heated (A LITTLE HUMOR)