Welding 3/4 in mild Steel

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HelloI have a some bar stock that is 3/4 inch thick by 5 inches wide I would like to  take two 10 long pieces and but weld them together.  I have a BetaMig 250 and have welded plenty of 3/8 thick steel but nothing 3/4. What are your suggestions to weld them. I also have an older Miller AC/DC ThunderBolt  Arc welder, but I have a lot more experience with Mig welding. I am going to use the joined steel to make a push plate for my new logsplitter.
Reply:woodtick007,Generally, you want to bevel the edges that are going to be welded. Depending on how they are going to be installed in the log splitter, you might need 100% penetration. If not, then bevel them about a 1/4" deep on both bars on both sides. If you are getting good fusion & penetration on your 3/8" plates, then you should be able to weld 3/4" too. To keep them flat, clamp them to a table, weld one side and then flip over to weld other side. Good luck.Weldtek
Reply:Just for a push plate and only 3/4 inch I'd give both pieces about a 30º bevel for 1/2 the thickness on one side, little gap of course, run a root pass down that side (tack the heck out of the ends to hold the gap), flip it over and gouge a U groove ( actually a double J) on the other side. The narrower groove will help cut back on the filler and passes.  Watch and correct for bowing tho. You'll be flipping this over a lot and using some healthy clamps, maybe a thin wedge underneath."The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:I would double bevel, with a slight gap. Attached ImagesDon’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:Would it be possible with the Hobart Beta-Mig 250 to spray arc transfer weld that in one pass or each side?  I currently have 75-25 and 95-5 gas bottles..... Would I just set the power at tap 9 on high? How would I adjust the wirefeed settings to spray arch transfer?  I also have a Millermatic 250 but to be honest I feel the Hobart has a smoother arc with better arc starts and no burnback problems.Last edited by woodtick007; 10-17-2010 at 03:55 PM.
Reply:Originally Posted by CEPI would double bevel, with a slight gap.
Reply:If you want to do spray, use your 95/5 gas.  You're going to have to experiment a bit with the settings, since your machine probly doesn't have adjustment graduations noted in volts and ipm.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:Originally Posted by CEPI would double bevel, with a slight gap.
Reply:Like mentioned bevel out both sides and when welding alternate between sides.I just welded up some 1" cast. The bevel on each side was about 1" wide at the surface.
Reply:counter the bow ,in the opposite direction .. practice on some scrap before you start.. the picture of the double bevel is the best option , also the use of a couple of good clamps are strongly advised ... good luck ... let us know how it turned out ..
Reply:Originally Posted by woodtick007I have been a little slow on this project......lol but I sold my old splitter and revisited this project today.  I am very concerned that even clamped that after mig welding my root pass on the first side that I will get bowing as the weld cools.   Can anyone please lend a little insight to keeping the final product straight/without a bow?  Also its mentioned to gouge a Double J groove..... I have some 5/32 6010 rod  and a 250amp dc welder, but I am a little confused as to how to exactly complete the double J. As always thanks for your help with this