Welding in a Tunnel - Problems

[crash325]

What I thought was a simple change to the wood stoves that I build, sure created a problem. To go from just a heat stove to more of a cook stove a 7 to 8" section of the tank was removed, so that the top plate gets direct heat.

Welding 18" inside a 14" tube turned out to be a real pain. Plan was to tack it down in several places then come back & weld solid. #1 Problem was this tank was thinner than most of the other tanks that I have used. Under 1/8", about .0100. #2 The 18" cuts were not perfect, very close but some small gaps. Using 1/8" #6011 I started a 100 amps. Way to hot so I worked my way down all the way to 40 amps. A little hard to light & maintain an arc. But it was a lot better and less burn through on the water tank. Used some 3/32 rod, no real gain and less fill. Using "splash & dance" ( weld on top plate up close to tank, quickly dance onto the tank.) Managed to get most of the burn through filled. Even with welding a little here and there the top plate warped real bad.

Most of the problems are probably the welder, but I can't replace him.:laughing:
I think 1 answer to the problem would be a wire feed welder, but at this point that is not an option. I had a 50"# box of Murex 1/8" 6011 and really liked it. Had get some new rod, picked up a little box of 6011 at HF. Turned out to be great rod, it would run at 40 amps with almost no slag. Picked up a 5# box of Lincoln Weld, thinking how much better it would be than the HF rod. Wrong, wouldn't run at 75, or 90. At 110 it would barely run. To get any kind of a decent bead I'm up to 145 amps, lots & lots of slag.

Had some Lincoln Weld 3/32 6013. It welds pretty good at 40 amps, much better at 60 or 75. Does not burn through like the 6011. Will use it on the next stove.

Suggestions Please. Other than "replace the welder" and a wire feed welder.

 

[k0ua]

Take this for what it is worth, because I aint a real welder, nor do I play one on TV, BUT, I think you have already answered your own question. the 6013 is a low penetration rod, and of course you need smaller rod, 3/32 or maybe even go down to 1/16 6013, which is available at you "box store" Lowes. who knows what the real amp setting of your welder is, they all vary, you just have to keep adjusting until you get it right, but 6011 is a deep penetration rod and 1/8 is big for 1/8 inch material. I would probably try 3/32 7018 first if it was me, at about 60-65 amps, just because I really like 7018, but the 6013 can work well, just get some small rod, keep turning down the welder until you get good results. There 2 cents from a guy that wouldn't make a pimple on a good welders.....

James K0UA

 

[Shield Arc]

I'm not real good with thin material my self. A MIG welder would be my first choice. But here are a couple suggestions. Make a lot more small tacks, maybe only 1 inch or 1 1/2 inches apart. Weld from one tack to the other, but back step! And move around a lot, make one short weld in one area then move to the opposite side.
Another trick, knock off the flux of one rod and use it like filler rod when Tig welding or O/A welding.

 

[IslandTractor]

I'd pick up a cheap 110v wire feeder and use 0.030 fluxcore. Even a Harbor Fright fluxcore welder at about $125 on sale would do that job. Better would be a true MIG with 0.030 or 0.024 but even a used setup with gas would likely run $500.

 

[crash325]

Welding inside a 14" tube does not give much room, not enough for 2 hands and any vision at at all. What I call splash & dance is a quick pass, about like a tack weld. I was moving from place to place to avoid heat build up in one spot.

2 things that may have made a difference is the humidity & temp. its down around 10%. Last summer welding with 7018 5/32 or 3/16" humidity around 30%, very warm days, it ran well at 180 amps. This winter, low humidity, cold days & metal it would barely run at 225.

But the real big difference is in the rod. Murex 1/8 has been used on 3 previous stoves. Very few problems, in all weather conditions. Harbor Freight 1/8 worked well down to 40 or 60 amps. Lincoln 1/8 a real pain. All were 6011. 6013 3/32 by Lincoln ran real well. :confused2:

 

[crash325]

I'd pick up a cheap 110v wire feeder and use 0.030 fluxcore. Even a Harbor Fright fluxcore welder at about $125 on sale would do that job. Better would be a true MIG with 0.030 or 0.024 but even a used setup with gas would likely run $500.

As I said up front. A MIG or TIG was not an option at this point. A $125 machine would be so limited that it would be almost useless for most projects.

Just a side Note: Once welding outside the tunnel & off the edge, most of the welding went pretty well. No blow through anywhere.

 

[sandman2234]

Interesting, as my welder requires a minimum of 75 (hard to get started at that setting) and usually 90 amps, but I can stretch it to 105 for short periods if I need extra heat, but the rod typically starts overheating. No way could I run 1/8 6011 at 40 amps, just not good enough!
David from jax

 

[travis potter]

I weld a lot but am not a welder, don't claim to be but I weld nearley every day and most of it is 16 and 20 ga. I use 6013 3/32 Lincoln with a 90 amp inverter set at about 3/4 of the dial depending on the length of the elect cord. You might try welding blind if you can see the back side of the weld justlook at the back side and have the rod on the inside strike the arc and follow the weld by looking at the red metal with practice you can get a very good weld this way.

 

[crash325]

I found some problems with the welding machine. Ground clamp was dirty & rusty. Cable to clamp connection was bad & cable was heating up. Got all that fixed. Rod would wiggle around in the clamp. Filed out the "V" and cured that problem. Things got a little better, but not real good.
Last weld in the tunnel is complete, baffle is welded in. Went pretty well, one small blow hole.

Went to 3 stores got some 1/8 7014 rod. No 1 had 3/32 or 1/16Th. New welds on outside of stove got a little better. Still have the problem of a shaky welder that don't see so well.

7014 Welds pretty good, but does lack penetration. OK for a job like this one. Will run it hotter on something that needs strength and more penetration.

Tank material is only about .085 thick. But think it has other problems as well. Crappy Metal? Sort of like fence "T" posts, just run away from a weld. Tank coating or minerals inside it?? Edge welding a real pain, quick welds on the outside away from a edge goes pretty well.

Damper is welded in. Split cut in "C" iron to flatten top of stove is welded up. Some early crappy welds were ground out and re-welded.

 

[Iplayfarmer]

I see you have some of your problem fixed. I too have had issues welding on thinner stuff, but I found the answer in 1/16th 6013 rod. I run it on the lowest amps that will still start an arc and keep the arc really short (i.e. keep the rod close to the puddle).

I know that 6013 is lower penetration, but that's the point isn't it? If you're blowing through, you have too much penetration. I'm a poor welder, but I can do pretty thin stuff now that I have that tiny rod.

Another trick that I have heard, but haven't tried is to switch your welder to AC to get less penetration. You might also try electrode negative.

I got my 1/16th rod from the fastenal guy that delivers at work. I'd think you could find it at an Airgas, Norco, or other welding supply store.