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Joining thick and thin with SMAW

First, a report; then a couple of questions ...

I was repairing a cheap day-bed frame yesterday, and discovered the joys of trying to stick weld thicker material with very, very thin material. The piece that I was repairing is the "backrest" or "headboard" of the daybed -- the part that spans the long side to make it more like a couch when pillows are set against it. There are two pieces of thin-wall tubing that run across the width, and they are joined together vertically with solid rods of about 5/16" diameter. After repeated stress produced by young children playing on the bed, the rods had all pulled out of the tubing; to be more exact, the places where the rods were tacked onto the tubing had ripped out, leaving a hole in the tubing. (Only one small tack per rod; looked like it had been done with MIG.)

I wanted to weld it all back together, and oh how I would have liked to have a TIG machine to do it ... but all I have is an old AC stick machine. I gave it a whirl, using 3/32" 6011 at 45 amps, and eventually wound up more or less successful; after I finish grinding, it probably won't look half bad . But as you can guess, I blew more than one hole in that thin tubing. (Basically, if I even thought about putting the arc on the tubing for more than a few milliseconds, it was gone!) Obviously, it would have been nice to run at lower amps, and theoretically my machine goes down to 20 amps ... but I've never been able to strike and hold an arc with any consistency below 45 amps.

I don't know exactly how thin the tubing is, but you may be able to get some idea from the pictures I took of one of the holes that I blew in it. (I ground off the mess; a couple of pictures include a 3/32"

6011 rod to provide perspective.) It definitely is a good bit thinner than .062," which had been the thinnest stuff I've ever even thought about stick welding up to now. Here are links to the pictures:

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I finally began to have the most success when I would strike and hold the arc on the solid rod, and then just flick it down for a fraction of a second onto the tube, and right back onto the rod ... another quick flick and back ... until a fillet joined together. In some ways, I think I was mostly melting the end of the solid rod down onto and into the thin metal, more than actually melting the two metals together in the way that I usually think of when welding. I was able to fill a couple of small holes that I blew into the tubing right next to the solid rods in a similar fashion, except basically keeping the arc on the solid rod the whole time (except at the very, very end). When I tried to flick over near the hole, even for a fraction of a second, I got a bigger hole (hence the pictures above!), but if I let the arc melt and "wash" the solid rod down over the hole, then I could flick over briefly with the arc to try to make sure it all joined together.

It took awhile, but I did eventually succeed also in filling in the two bigger holes that I made (including the one pictured above). At first, I attempted to lay on a patch of some .062 (or maybe a little thinner) sheet metal and weld it on ... bad idea, or at least it just resulted in more hole than before. What finally worked was to cut a piece of 1/4" solid rod and lay it across the hole, then strike and hold the arc on the middle of this rod until it began to melt into the hole; then I could work out towards the ends. But I had to be careful, because at some point the whole piece of 1/4" rod would start to sag down rather quickly. I don't know how well joined it all is, but the holes are covered, and it appears to be continous metal after I grind out the lumps.

Now, some questions:

1) Would there have been a better way to do this, given the equipment I had at hand? (Yes, I know -- TIG would have been so much better, and maybe even MIG ... but all I have is the AC stick machine.) Who has done this kind of welding (thick and thin, using SMAW), and how did you do it?

2) Is it generally possible to strike and hold an arc at less than 45 amps -- is this just my lack of technique, experience, etc., or shortcomings in my machine?

3) Would I have been happier with a different rod? I don't think I can get 6011 any smaller than 3/32, but I know I could get 6013 in a 1/16" rod. I've actually got some 7014 in 1/16" ... but I've never had much luck using it. It is no easier to strike an arc below 45 amps with it, and it tends to bend far too easily ... and I can't freeze the puddle like I can with 6011. I knew there was no way to run any sort of stringer on this repair, and I am quite sure I would have done nothing but melt holes if I had tried ... so I didn't even try to use the 1/16" 7014 on this job. But I keep reading that "6013 is for sheet metal" -- so would I have had better or easier results if I'd bought some 1/16" 6013? If so, what sort of technique would I need to use?

4) Would it have been possible or helpful to add some filler to the arc? I wondered if I could have fed in some filler rod to help cool the puddle ... but on the other hand, I don't know that that would have helped any when it came to blowing holes in that thin tubing. There wouldn't have been time to feed in filler before blowing out a hole. Bottom line: I need a TIG!!!

Your comments and suggestions requested!

TIA,

Andy

Reply to
Andy Wakefield
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Your last question is the answer to the problem. It takes a bit of practice but you can weld thin stuff with the electrode plus another electrode with the flux knocked off in your opposite hand. You end up welding with the arc half on your inserted wire and half on the parent metal. Your tactic of keeping the arc on the thicker piece is correct. When you next purchase E 6011 look to see if you can get E 6011 P the suffix indicates extra potassium to make the arc more stable. It should make your 45 amp setting doable. Randy

Reply to
Randy Zimmerman

Randy, many thanks for the response. I'll have to try out the technique of feeding in a "filler" rod. Meanwhile, it sounds like the technique I stumbled on, after trial and much error, was basically on the right track?

I will look for some E6011P (I did not know about this!!) -- you said it would make the 45 amp setting doable, but would it allow a lower amperage? Say 35, or even 25? In general, what is the lowest practical amperage at which one can strike and hold an arc, and with which electrode(s)?

Again, many thanks!

Andy

Reply to
Andy Wakefield

I am sure there is a power supply somewhere that would allow you to run ten amps. The arc characteristics of the transformer has a good deal to do with it. The potassium addition helps in maintaining the arc under marginal conditions. . The first time I heard of the second rod was from a lady welder who used the technique to join up ventilator ducting when working for Motor Coach Industries in Winnepeg. That was 25 years ago. In those days wire feed machines using light gauge wire were rare. Randy

Reply to
Randy Zimmerman

Reply to
Roy J

6011?? - yer kidding! 6011 rod is WAY too agressive for this thin stuff in my opinion - its not rusty, so you don't need it. Get some fresh Lincoln 6013 rod, turn the current down, and have at it. 7014 at low current is also very smooth and stable, but 6013 has much less penetration, and smoother to run on this thin stuff. HomeDepot carries Lincoln 6013 in both, 3/32, and 1/8.
Reply to
Mr Wizzard

The idea of using 6011 is that the flux is minimal. Since it relies on a gas cloud of carbon dioxide for primary shielding you can hold an excessively long arc. As soon as you pull a long arc with '13 you lose shielding and get slag inclusions. 6013 is great on thin material if the fitup is perfect and you move quickly. Randy

Reply to
Randy Zimmerman

Thanks for the input. Have you run 6013 on something this thin, and especially in this situation of joining thicker material to thinner material? Farther down in my message, you'll note that I considered using

6013, as well as 7014, but in the past I've actually had better results with 6011 on thin material than 6013 -- because of the ability to freeze the puddle. (Yes, you do have to move right smartly to keep from blasting through ....)

If you've run 6013 in this situation, what sort of technique did you use -- can't run a stringer, but need more than just a tack because of repairing the places where the previous tacks ripped out.

All >

Reply to
Andrew Hollis Wakefield

Reply to
Andrew Hollis Wakefield

I find E 6013 an ideal rod for welding up chain guards and covers on mill machinery. This is new material ranging from 14 gauge to 10 gauge. the joint is open corner but tight. After tacking together tilt the unit so that the joint is sloping 45 degrees. You turn the amperage up not down. I use 1/8th rod at around 125 amps and starting at the top quickly drag the tip of the rod down along the corner. You must keep ahead of the flux and have the rod pointing upward. If done right it is faster than using MIG. E 6013 is described as a fast follow rod meaning that you can travel faster than other rods and the bead will follow although it does thin out. Randy

Reply to
Randy Zimmerman

Once again, Randy, you have answered a question I didn't even know enough to ask! I had heard the "fast follow" designation, and I had observed that characteristic of 6013 (mostly when trying to teach someone how to weld for the first time, and seeing them move way too quickly for normal purposes!), but I had never put that together. Many thanks!

The technique you describe sounds really cool; I'll have to experiment ... but a couple of questions: What about thinner material (e.g., what I was welding was probably more like 18-20 gauge). Also, is the slag hard to chip when you do this?

Thanks again!

Andy

Reply to
Andrew Hollis Wakefield

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