Self taught welder needs some advice on a technique

Booster · Dec 11, 2010

Helo, Let me first say i have bought a lincoln arc welder about 3 years ago and just started welding and learning by doing. I've read up on welding to some degree also.

I have a couple of particular geometries i am welding together and i have become so frustrated with myself that i cannot get a good weld.

My camera is broken so i cannot yet get a photo of this so allow me to form a picture for you.

All is mild steel and about 12 gauge.

I have a small cylinder i am welding to a large cylinder. Imagine a 12" dia can sitting upright. Made from 12 ga rolled into a tube. I am welding to it another cylinder shape, and it is also oriented upright. It is 4" long 3/4" dia and also about 12 ga thickness. Where the two objects meet, i am trying to form a beed on both sides.

I was told to weld these when upright and use about 30 deg up. Also using 6013 rod 3/32" size. It seems that when the rod melts down into it, it is so unpredictable and sort of pulls into various directions. It globs and forms gaps. I recently tried laying a piece of welding rod against where the to curved edges come together in hopes that this would aid in filling it in.

I have a garbage wire feed welder from harbor frieght that i never use and i realize that wire is probably gonna be easier, but i would prefer to master the arc welding on this first.

Any tips on this?

If i left out some details, let me know. I think i covered it and hopefully you can understand the parts i am welding together.

Booster · Dec 11, 2010

Also, i am using about 75 to 90 amps on this. Too high?

Kingbob · Dec 11, 2010

are the tubes side by side like beer cans in the fridge or end to end like when you buy two beers at the same time and hold them in one hand?

Booster · Dec 11, 2010

Yes exactly, Side by side like beer cans. Its where they meet that seems to take a weld unpredictably no mater how i angle it, swirl, stitch.. etc.

El Mustachio · Dec 11, 2010

just a thought

With 12 ga mild steel I much prefer an Oxy Acetylene weld over smaw (stick) or gmaw (mig/wire). I've found it's much easier to control the size and shape of the weld bead this way. Again, just a thought, I'm not a certified welder but have enough experience to know when I want to change techniqes.

Clive603 · Dec 11, 2010

I guess your Lincoln is the normal AC buzz-box type of arc welder. If so it might be worth trying a DC output converter.

I have a modern Fronius brand inverter welder with DC output which will produce decent welds in similar geometry by "simply" drawing the rod along the joint. Simply is more a statement of appearance than fact as you need to get rod size, current, draw speed and angle just so. The guy who showed me made it look effortless. I've tried similar things a time or two with the usual "don't really know what's what" hit and miss results. But the hits are really good so I've no doubts that if need were sufficient I could master the art. My demonstrator said it was the DC bit which makes most of the difference.

Perhaps someone here knows more.

Clive

S_W_Bausch · Dec 11, 2010

I own a welder, that is waaay beyond my abilities, so I can't blame it.

You aren't getting adequate heat, where you need it. And while you think you have a tight fit, in terms of not seeing through that area, keep in mind you are actually trying to fill a deep fillet.

Nothing wrong with 6013, though that's not chiseled in stone, here, since you have so much metal soaking up the heat.

6011, 6010, if you have them, try them, I won't say buy them.

I am afraid to say this, but I would get a larger rod, and perhaps shim those pieces out a bit, so you can see daylight.

Now you can stick that heat where it needs to be, on that tangent, and a thicker rod to fill it in.

I would do it flat, and start with tack welds every inch or so.

See how that goes, I have no opinion on amps, at this point.

macona · Dec 11, 2010

By welding them like this it is not really a proper joint. You need to add in a piece of filler strip and weld both pieces to that. Something like a piece 1/4 to 3/8" rod on each side would do.

gbent · Dec 11, 2010

You designed a booger of a joint to weld. I would go one step further than macona and cut a piece of 12 gage material about 1" wide. Put it across the joint the wide way. Now you are welding two pieces of 12 gage together, one joint will be close to a fillet, the other more like a lap.

dsharp · Dec 11, 2010

Are you starting at the bottom and trying to weld up or at the top going down? Start at the top and use your rod to control the puddle. Sounds like your letting the rod get too far away from the puddle. If you could get someone to show you I think you would pick it up pretty quick.

Booster · Dec 11, 2010

dsharp, yes i've tried every angle, position. I'd try weldin it buck nekkid if i thought it'd help. I think you guys hit on it though. I may try a spacer now. I didnt realize this was considered hard one by experts also. I shoulda posted this awhile ago. I'll try this next im at the shop. Thanks guys.

S_W_Bausch · Dec 11, 2010

Good Luck,

I am thinking you need a larger rod, and the ability to get that heat closer to the tangent of the cylinders, hence the gap.

Once the heat is there, you will most likely need to weave from one side to the other.

If you have ever stuck caulk in a 1/2 - 3/4 inch gap, you know the drill. Stick the caulk to one side of the gap, work the nozzle to the other side and stick the caulk to that side, then repeat.

Of course, with the welding, the gap is more like 1/16 - 1/8 inch.

metalmagpie · Dec 12, 2010

Crummy joint design. But if I had to do that, I'd punch (or drill) a series of 5/16" holes vertically in the larger diameter cylinder, so they run right up the line where the cylinders join. Then clamp in place, turn the whole setup horizontal, and plug weld through the holes.

I consider 11 gauge to be the thinnest stock that most guys can stick weld. So doing *any* stick welding on 12 gauge is dicey at best. This is a job for MIG.

If you do manage to get two hot seams up the sides of your joint, it will very likely warp your cylindrical shapes way out of round.

Lots of times when I have to do something like this, I'd cut out a couple pieces of plate steel so each has a circular indent on two sides, to fit your two cylinder ODs. Then weld one pair to your smaller cylinder, then put it against the larger cylinder and weld the plates. Don't weld the cylinders to each other; rather, weld both to a pair of plates which then hold them rigidly in position. They won't be tangent that way, though.

metalmagpie

courtiron · Dec 12, 2010

tube welds

While I am not much of a 6013 fanboy, It should work. I would use 6010 cause I'm an old fart who was raised on it.

I know the range for 6013 lists out at 40 to 90 amps, but I would definitely stick to the low side, possibly 45 to 55 max. Unless I missed it some where you don't say if you are using AC or DC. If you have a DC machine try DC electrode positive ( reverse polarity ) and see if that helps.

While the joint design will cause a lot of shrinkage and therefore warpage because of the relatively large weld fillet, you might try welding the ends of the small tube to hold everything in place and then use a couple of 1" passes on each side opposite each other to minimize the warpage.

I am not an engineer, but I don't think that you would need to weld both sides of that joint full length to be as strong as the 12 gage metal.

kgize · Dec 12, 2010

As other have mentioned - You have setup one of the hardest joints to weld…although I too find myself often wanting to weld a cylinder to cylinder parallel to each other (pipe to pipe parallel). The problem is the narrowing gap where the cylinders meet at line – this gap continuing far back beyond where the arc will go and hence an air space behind the weld. The advise to first fill the gap is key – if you fill the gap with a rod, although better than no fill at all, you still sort of have the same issue in that you are welding a cylinder to cylinder. If you can fill the gap with a triangular piece that fits the gap well and so the gap has a flat ‘bottom’ – works well for me. In lieu of filling the gap, assuming you are not burning through, here’s what works for me but most will tell is ‘wrong’…. I find using the thinnest rod I have – the thinner the better - and jamming it hard into gap - not caring that the rod is touching both sides of the cylinder ( against ‘good’ welding practice) - just trying to get weld as deep in there as possible - will get the best root weld – although still not pretty . Then you have to tediously clean the heck out of that (usually slag encapsulating) root weld – then passes on top of that with whatever rod is appropriate will go more ‘normal’ . I am just an amateur – go-fot-it-weld-what-I have-on-the-ranch…but that’s what works for me from trial and error in many attempts welding a cylinder to cylinder - e.g pipe to pipe parallell

Chris Foley · Dec 16, 2010

I agree with the other posters that your cylinders will warp from this sort of weld.
Also, DCRP will allow better penetration and control than AC. A general rule of thumb when stick welding - use the highest heat that allows you to maintain control of the puddle. I'd try 90 amps first. Even though the metal isn't that thick, there is a lot of it around the weld joint to suck heat away.

I don't think that this is a difficult weld joint for SMAW. The 3/4' dia tube is small enough that the root isn't very deep.

Welding flat is a whole lot easier than vertical. Can you tack the pieces, then lay the assembly horizontal to run your beads? You should do two short welds on one side, weld the other side fully, then go back and finish the first side.

Booster · Dec 17, 2010

Thanks everyone for your input. One of these suggestions will solve this problem im sure. I'll head out today and try. Macona, i was leaning to that solution too. Was wondering if i can just use nails due to abundance and sizes.

bruto · Dec 19, 2010

As a fairly lousy welder myself, but with years of lousy welding behind me, I agree with Macona. If you use a couple of pieces of something like 1/4 inch rod, you will avoid having to weld deep into the crease, and you can then control your penetration much better. You'll also end with the cylinders essentially joined by two separate weldments, less likely to tear apart if there's any bending stress between the two cylinders.

mm58 · Dec 22, 2010

Booster... unless 12ga is too thick, this sounds like a perfect job for a spot welder.

Just a thought...

Mike

Self taught welder needs some advice on a technique

Cast Iron

Cast Iron

Stainless

Cast Iron

Hot Rolled

Titanium

Diamond

Diamond

Diamond

Aluminum

Cast Iron

Diamond

Titanium

Aluminum

Cast Iron

Aluminum

Cast Iron

Stainless

Hot Rolled

Similar threads