Need advice / lesson on welding thin steel

woodlandfarms · May 9, 2012

I have a lincoln tombstone AC/DC and am self taught for the most part. Classes are not an option, neighbors look at my work and say its nice but don't seem to offer up much more education.

So, I need to weld thin steel. I did it once before with a nice miller mig.

What I learned from the mig was not to try and push a puddle but to just draw a straight line. But I am really messing up with Stick.

I am talking 1/8" square tubing for the moment.

So, can someone talk me through the basics or point me to a video that shows it being done? I figure a small rod, low amps, pull straight and practice, but so far I am either punching holes or not getting any glueing action.

Carl

ultrarunner · May 9, 2012

We did all the thin material welding with a tig setup... the heat is controlled by the foot pedal.

Some of my home project were with Oxy-Acetylene and came out very nice.

The shop also did a lot of mig on thicker material... built a dump trailer there years ago and having the mig with the overhead crane to use was sweet.

As with most welding... it helps to stitch or tack weld so all the heat is not concentrated just in one area.

Gary Fowler · May 9, 2012

If by 1/8" square tubing you mean that is the thickness then it shouldnt be a problem to weld. IF you position it so it is slightly down hill by maybe 15-20 degrees and use 3/32 6011 or even 7018 rods you should be able to weld it a bit at a time. You wont be able to just keep welding. Try running about a half inch and allow it to cool. Then flip it and weld the opposite side same amount and let it cool till it is no longer red hot. Keep switching sides and welding a bit at a time until you get it all welded. This works for me with DC machine. Just watch the metal till it starts to glow orange (just before you blow a hole in it and stop) A little practice and observation will tell you when to stop and let it cool. 7018 ran slightly downhill will give you a smooth weld and not burn so many holes. Point the rod uphill at about 45 degree angle when the slag startst to try to pass your rod it is about time to stop and let it cool. Chip the slag before you start welding in that spot again
With that thin metal you need a 0 gap so keep it tight. When tacking it together, tack opposite side after first tack, you will have to hammer it a bit to get it back square due to the tack shrinkage. Get 3 tacks and then start your weld on the 4th side.
I build a trailer hitch for the receiver on my Kubota RTV out of 1" x 1/16" tubing using this method and 3/32" 7018. I can pull all the Kubota has traction for in 4 WD and it holds good. I think actually it has a double wall tube within a tube that was 1/16 thick. I made it from the fold up legs from a road sign. I got a 2 truckloads of wood chips and the trucks dumped it out in a pile. Later when I was spreading it out, I found the mangled sign holder frame. I took it apart and was enough to make 2 hitch inserts and parts left over. After putting them all together, I had 1"x 1"x1/8" thick bar that just fit in the receiver hitch for my Kubota. I had a solid bar stock one that I bought and salvaged enough steel and tubes to make one for me and one for my brother in law. Now I have one front and back so no more swapping around. I like to push my boat in using the front but if I am pulling trees, I hook to the back usually.

Anyway try my suggestion and let us know. By the way what are you building

LD1 · May 9, 2012

For starters, what rod are you using?? And how many amps?

1/8" should be no problem with a stick welder like you have.

I'd forget the 6011. And (in my experience only) 7018 EVEN 7018AC dont weld well with a tombstone.

For the 1/8" on THAT machine, I'd get some 6013 or 7014 and run about 90-100A.:thumbsup:

flusher · May 9, 2012

6011 is a deep penetration rod--don't want to use that on thin steel.
3/32" 7014 or 7024, DC positive, low amps (80-100), move the puddle fast
to prevent burnthrough but slow enough to get good tie in at the edges of the puddle. Practice on some scrap before tackling the good stuff.

Good luck.

lostcause · May 9, 2012

i've done 1/8" thick with good results even using 1/8" e6011. set somewhere in the 65a-75a range, and the trick is not to stay in one place too long. to avoid starting and stopping, what i do is to make a very exaggerated c-shaped weave. you will have the puddle behind you at the seam and as you weave back and forth, so make sure to pull ahead and out from the puddle more than usual. you will see the puddle start to cool slightly, and as this happens, weave back through the puddle. rather than keeping a molten hot puddle constantly you will have it cool slightly as you pull ahead of it and then heat back up as you come through. this should help keep the heat low enough so you don't constantly melt through. it does take a little practice, but it's not hard to do.

woodlandfarms · May 9, 2012

I had 1/8 6011 at 90 a dc+. Going to have to go up up Longview for something more than 6011 or 7018

Would you guys suggest 1/8 or 3/32. I am inclined to get the smallest but.....

Carl

Soundguy · May 9, 2012

i have an ac buzzbox.. a hobart 235xl. when i weld thinwalled tube like that 1/8 you have, I use a 3/32 6013 rod.. test out the amps.. but you find something between 70 and 90

remove any paint or rust.. that 6013 won't blow it off like a 6011 will.. but does make a nicer finish.. I've had less accitental blow thru ont he 6013 than 6011.

for thiner stuff, I have a 30/70a CH stick welder that i use 1/16 and 5/64 rods with.. but that's for like sheet metal.. etc...

soundguy

soundguy

cowski · May 9, 2012

i think it would be easier with 6013.i would get 3/32.set it on dc at about 60 amps.

LD1 · May 9, 2012

Soundguy said:
i have an ac buzzbox.. a hobart 235xl. when i weld thinwalled tube like that 1/8 you have, I use a 3/32 6013 rod.. test out the amps.. but you find something between 70 and 90

remove any paint or rust.. that 6013 won't blow it off like a 6011 will.. but does make a nicer finish.. I've had less accitental blow thru ont he 6013 than 6011.

for thiner stuff, I have a 30/70a CH stick welder that i use 1/16 and 5/64 rods with.. but that's for like sheet metal.. etc...

soundguy

soundguy

Yep, 6013 is much better for thin stuff than 6011. And 1/8" thick tubing should be easy with 6013. Its not exactally sheet metal.

Soundguy, have you gave any 7014 a try. I honestly cant tell a difference in how it runs compaired to 6013. But it is a 70 series rod so its a tad stronger.