Tips for 11 ga square tube to 1/2" plate

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Hi folks,Having trouble welding mild steel 11 ga / 1/8" square tubing to 1/2" plate.  Butting the tubing end against the flat plate for a welding table.  Using stick on an Idealarc 250.  Of course, as a mere Bed Frame Welder (TM) I can't "handle the heat" -  blowing holes in the tubing and the opposite problme of sufficient fusion with the plate. Positions - flat, horizontal and vertical (I tried them all)Joints - most are filet but on one side of the tubing, it's flush against the 1/2" thick edge of the plate, so it's more like an outside corner.Electrodes  - 1/8" 6011 DC+ at mid to low amperage ranges (110 to 80 amps) and 3/32" 6013 DC+ at mid to low amps (90-70) - I figured higher amps was just going to make things worse.I'm keeping the electrode a lot more on the plate, but still finding the tubing melting back unless I really hurry.  I tried aiming on the plate so much that I get a pile of weld metal on the plate and a gap with the tubing.  I'm then concerned I'm not getting any penetration on the plate.  Tried slight weaving quickly back and forth with a slight pause on the plate, drag, little circles, all with most of the heat pointed at the plate of course, and also very little time on the tubing. Searched for tips in the bible and New Lessons but most of what I see is same thickness materal welded to same thickness.Any tips, maybe welding downhill or maybe overhead filets with the plate on top and the tubing lower? Preheat the plate?  Would one position be easier than another?  Admit defeat, keep my day job and hire a pro? Thanks for any advice
Reply:I would like to know that what others say, I cant say I have tried to stick such different thicknesses together ever , and havent stick welded in a year or so. Mig would be no problem but with stick, ehhh...
Reply:I will be watching this too. I am getting ready to do the same thing this weekend on my welding table I am building.Did you build a frame for the plate to sit on or you welding legs on to  the 1/2" plate?Syncrowave 250MM130
Reply:Hey RodJ, long time no speakee!    It sounds like you generally have the right ideas.  I just read my post below, and realized it's pretty long.  So here's the summary of what I've said, and then you can read the details below if you want:1. Turn down your amperage.2. Try electrode negative if necessary.3. Don't long-arc, if you are.4. Don't make your bead too big.11 gauge is basically 1/8" wall thickness, so each of your fillet welds except the one where the edge of the tube is flush with the edge of the plate shouldn't be too bad even with the 1/8" 6011.  For that last weld, it would solve a lot for a BFW like yourself if you could redesign it and move the tube further out onto the plate.  Even if you could move it the width of the fillet, that would help a lot.  Basically you want to use the plate as a heat-sink for your weld, which includes aiming the rod mostly at the plate, and spending most of your time on the plate as well, which you're already doing.  It IS possible to weld it exactly as you have it designed, just a little more difficult for a beginner.Have you tried switching your polarity to electrode negative?  That will help reduce the rod's penetration.  Also, if you're burning through, turn your heat down and/or speed up to slow deposition in any one area.  I haven't used an Idealarc before, but if I were running one of my machines I'd have that 1/8" 6011 at 85A tops, certainly nowhere close to 110A.  Remember that each machine is an island to itself, and just because the dial says 80A doesn't mean that's what you're getting.  Try turning it down a little more and looking at the results.  Test it destructively if there's any question.  I also don't weld sheet-metal, and can count the number of 6013 rods I've run on the fingers of one hand.  However, you don't need 6013 for this -- 1/8" 6011 is entirely capable of doing what you need.  Remember that 6011 needs to be run differently than 7018.  With 6011, you'll need a forward-step, back-step motion to let the puddle slightly solidify and then get your rod back into it.  Remember that the 1/8" wall tubing can only take so much heat, which means your weld bead will be smaller and your travel speed faster.  Trying to make a big fat bead will introduce more heat than the material can stand and it'll break down on you.  Generally a fillet weld only needs to be as big as the cross-section of the smaller piece, so a 1/8" to 3/16" fillet is all you need.  1/2" is way too big, for example.Also remember that if you hold the rod end too far from the puddle, you're slightly increasing the amperage.  If you get too far away, the rod will snuff out, but you don't want to be long-arcing at all in your situation.  Hold a fairly tight arc when dealing with thinner material - it keeps the heat down.Finally, post pictures if you dare.  Tough crowd around here, you know.
Reply:Fillet wels according to AWS D1.1:Penitration to the root but not beyond (paraphrased)You don't need a gob of wels and penetration beyond the root for a fillet is nearly pointless.
Reply:I never weld the top plate because it will warp. I bolt the top to the frame.Miller diversion 165Miller mig 211Hypertherm pm 30Milwaukee 6230 14 inch chop sawMd 45 mag drill (RIP; fell on its head)New MD 45! Thanks to the esposa!Finally got an O/A setup
Reply:Thanks, Tbone, but I'd rather post pictures of myself naked than post pictures of the snail trails and boogers holding my table legs together   I appreciate all the suggestions and the details - seeing as I have 4 table legs with four sides each, I'm going to grind them out one by one as punishment for not having tried this on scrap first.  Hmm, maybe I should get some scrap pieces of plate and tubing and practice a bunch before I jump back in?  Ya think??? Fat B - agreed - helpful reminder cuz I lost sight of that at first.Bolting.  Yup, there's always one guy that pops up and says, "you know, instead of welding it.... " JUST AFTER you've already jumped off the cliff.   If I had the tools to drill and tap, that would have been my first choice.  I really gotta make friends with a machine shop.
Reply:Originally Posted by RodJ If I had the tools to drill and tap, that would have been my first choice.  I really gotta make friends with a machine shop.
Reply:how is your fitup?  having a great fitup makes that situation much easier to weld.XMT 350 MPa, w/D52-DTA 185 TSWHarris of
Reply:One thing you can always do is set the heat for the thickness of the tube and weld around the end of the tube for the first pass, not worrying about the plate.  This gives the material a little more beef so on the next pass you can turn the heat up some to get some fusion into the thick plate. Just make sure to do a reasonable job of cleaning off the slag after the first pass.
Reply:11ga material would not need more than a 3/16" fillet. Single pass with 1/8" 7018 and all is good.Remember chains are only as strong as the weakest link. your weak link is.....11ga.
Reply:I was going to suggest to build a frame out of tubing and just placing the plate on top of it. And as they just told you, drilling and tapping ain't rocket science. And you don't need much precision either. I would just build the frame the best I can (make one leg adjustable so you don't have to worry about making it perfect), put the plate on the floor, the frame over it (upside down) and drill straight through the tubes and the plate with a pilot drill. Remove frame. Drill and tap the plate as square as you can. You will be right on top, so you can do it whitout much effort (bodyweight, you know). Then go to the tube frame and drill oversize. Like 10mm for an M8 bolt. That will give you room to adjust for a not-so-square tapped hole on the plate. Place the frame over the plate and bolt it down. Do the very same thing on the oposite corner. Then, with everything bolted down, you can go ahead and pilot drill in as many places as you want. Your plate won't move arround risking misaligment between holes in the tubes and the plate. Once finished, you can always shim the plate in various places to compensate for a rocking frame, bent plate or whatever.On my first table (not a designated welding table at first) I did exactly what you are doing now and I still don't know how it can stay together after all these years. I bet there isn't more than 5" of good weld bead on the whole thing. Total welding noob at tht time. I didn't leave any overhang for clamping and the top is warped to hell. The bottom shelf is not recesed, so I bump my shins the whole time. I made the bottoms shelf from the same material as the top, which is overkill and plain stupid since I should have gotten a twice as thick top and an expanded metal shelf (or even a piece of plywood). Lots of mistakes.What I mean is that if I had known better, I could have done it propertly. You have the chance now to do it right the first time with all the advice everyone is giving you. True, it may cost you a few dollars more (for the drill bit, tap, tap wrenche, some bolts, etc. ) but you won't regret it in the long run.The summary goes as follows: build the best frame you can, get some basic tooling and bolt the plate to said frame.Good luck!MikelPD: I am making another table right now using and old rusty piece of plate as the top. I just finished painting the top. It may give you a few ideas. I am using thinner stock than you (40x40mm square tubing 2mm thick). I can lift the whole frame myself without much effort. Here: http://weldingweb.com/vbb/showthread.php?t=97611
Reply:Thanks, everyone, but I was past the point of no return to put some of the helpful tips to use.  I had already committed myself too far along.  It's a small table so I'm not out too much $.  Top is just two pieces of 8"x29" 1/2" plates spaced 4" apart so I can clamp from the middle or can fill that space with a 4" wide plate.  My first move was to lay down the top plates and tack a pair of 2" angle iron across them at the ends so they don't move.  Fortunately, I made it so there's an overhang on all sides... until I put a third piece of angle along the back edge.  Why i did that, I don't know because it adds nothing.  Waste of metal, welding rod, time and money. By the time I came for advice I'd already committed two of the four legs (2" square tube 11ga).  I can just cut them off and recut the ends which I might do since it will be 33 1/2" tall, losing a 1/4" won't make too much difference.  I tried some of the ideas when getting the second pair of legs on and it helped, though my position sucked so the welds are in hiding.  On the bright side, I was only off 1/32" on one of the legs, so 20 seconds with a grinder and the thing sits flat as a book.  The adjustable leg idea is brilliant.Now that I have a little table on wheels, I can get a lot more practice laying beads instead of lugging out and setting up the Workmate, heavy vise, clamps, etc.  As my skill improves I will make some mods, adjustable leg, grind / reweld so it doesn't collapse.  Will even replace the welds on the top with bolts (theres only a few inches of weld tacks)All in all, except for the 5" wheels, I only have about $30 in it.  The wheels more than doubled the price but two of them are dual locking casters - no swivel, no roll.I will preserve all these helpful suggestions and info and slowly rehab the poor thing.Thanks VERY MUCH!!
Reply:Mikel, I just looked at your project - very nice, and I could have saved myself some serious money if I'd thought of the wheel barrow approach to make mine mobile.  Another "doh!" moment.
Reply:I really don't understand the problem.  It's really pretty simple.Focus the heat into the heavier steel (the plate), and allow the filler to wash onto the lighter metal (11ga tubing)11ga 2x2 tubing welded to medium weight channel.  135amps 1/8" 7018.  Churn 'n burn 11ga diamond plate, again attached to heavier metal.  135amps 1/8" 7018 The plate should move very little while cooling.  It's mass will more than make up for the tendancy to warp.  Move to different joints while welding to allow cooling.6013 won't do any better job than 7018.  It has less stability in shrinkage, and will burn thru the same as 7018 if you don't weld properly.  "Any day above ground is a good day"http://www.farmersamm.com/
Reply:I liked tbone's suggestions.  I just welded some 10ga to some thick old rail road steel plate things, just for practice.  I used 6013 ("farmer's rod" on both DC+ and -.  The DC- worked better.  I'm thinking for a welding table (unlike a vehicle chassis or trailer etc..) it would work just fine.  As you probably already know, the 6013 rod doesn't penetrate like the 6011 does.  Many seem to absolutely despise 6013, but with some practice, I love the stuff for certain "specific" projects.  It might be worth a try...Then again, I also like what farmersamm said and it looks like from the pics, he knows what he's talking about re: 6013's performance characteristics.  Last edited by SuperArc; 04-28-2012 at 12:06 AM.Lincoln Power Mig 216Lincoln AC/DC-225/125Miller  625 X-Treme PlasmaMiller 211 Forney 95FI-A 301HF 91110Victor Journeyman O/PMilwaukee DaytonMakita  Baileigh NRA Life Member
Reply:Originally Posted by farmersammI really don't understand the problem.  It's really pretty simple.