Thread: Controlling leg length

One thing I'd suggest trying is running reverse polarity (DCEP) as it puts a bit less heat into the job. Dunno if it'll solve all your problems, but I find it better with thin sections.

Yeah, I usually do use DCEP. I was experimenting on the weekend due to (I think) reading that the RB-26s do particularly well on DCEN.

Originally Posted by Legion

Almost everything I weld is 3mm or less and yet checking my "banana" job, the leg length of the butt joint is ~8mm. Weld speed feels right, penetration looks right, it sounds right to my novice senses.
there's way too much material deposited. .

Fillet leg length is mainly affected by angle of electrode. Gravity is dragging the molten pool and slumping it out in the flat plane .Drop your hand (holding the hand piece) to direct the arc placement back up the vertical edge. try 30 degrees off the horizontal.Arc length may be a player here as well.If the arc is drawn too long,the arc pool becomes too big and runny and gravity pulls it down into the horizontal flat position.

Dealing with the banana shapes :try this ,
Unless the work has to be "sealed" why not opt for intermittent tacking? Less heat input is less heat to bend bananas.

A picture will be nice if you can manage it as its easier to give feedback.

Grahame

I inclined the job about 30° so that it was a bit like a fillet in the flat position. The weld was enough to completely melt the edge of the 3mm flat as well as penetrate the pipe. Arc length felt O.K. My starts are the worst part of my welds, and the ends are better but still not great so I like to fully weld to cover mistakes. Plus I want to learn to continue on from old welds seamlessly. And I still like to lay down as much weld as possible when all the equipment is set up, for learning purposes. Tacks would probably look better than bananas though. I'll take some pictures on the weekend if I remember.

Took a couple of pictures this evening.

bow.jpg

leg.jpg

The banana is bent about ~50mm out in the middle of the 2000mm length.

The weld leg length is about ~8mm wide. On the top is the pipe, on the bottom the flat bar.

I remembered that sometimes I felt the rod touch the flat bar, that's how short the arc was. I tried to keep it about the same ~2.6mm as the diameter of the rods. I'm O.K. these days with welding by senses (some of the time!) and it sounded right, not too hot or cold.

I'd love comments on the weld quality - I've got no teacher and am teaching myself via this forum and other online resources.

Firstly, a 20mm stitch every foot would have been more than strong enough for that job, and would have saved you from contraction problems.

Secondly, a but more travel speed would have given you a thinner weld. As it is, you've allowed the weld pool to fill up the void completely, which is natural, but if you want less material in the join, you have to draw the pool faster while still ensuring it's wetting both edges.

Apart from that, the welds you've done look fine.

Another thing you could try is "touch welding". It's where you strike the arc and let the rod burn, at its own pace along the join line with a slight downward pressure. It's what I use to teach new students welding basics. Also handy for those of us who suffer from "excessive welders weave".
Kryn

Looking at your your welding effort, I am pleased to tell you that there's not a lot wrong with it, perhaps just a fraction too fast.

It is the amount of welding and where it is placed. Are we looking at a fabricated fence panel with 25mm OD with 25 x 3mm flat welded at the 3 or 9 o'clock position on the pipe?

Can I take that the flat bar is being utilized a way of attaching the mesh? If so, a better way would be to attach it at the 6 Oc'k position and tack 20mm every 300mm as suggested, but at alternating opposite sides.

Pretty good effort otherwise.
cheers
Grahame

Originally Posted by Grahame Collins

Are we looking at a fabricated fence panel with 25mm OD with 25 x 3mm flat welded at the 3 or 9 o'clock position on the pipe?

Yep. Except it's a crude "lightweight" roofrack to fit on roof bars to stop smaller stuff than the gap between the bars falling through.

Originally Posted by Grahame Collins

Can I take that the flat bar is being utilized a way of attaching the mesh? If so, a better way would be to attach it at the 6 Oc'k position and tack 20mm every 300mm as suggested, but at alternating opposite sides.

The bar doesn't really do much in this case - it just neatens the appearance. The mesh/pipe welds are tricky - the mesh seems to go from heating up and not melting, heating up, heating up, then bam! completely liquid and burns through. The puddle is either nothing, or the whole wire. So the bar is to make it look neater and also slide onto the roof bars easier without any sharp edges. In other jobs (for fence panels) I do use the bar to weld the mesh to.

Yes, I did think of just wire to pipe at the 6 o'clock position but I wanted the mesh to sit flush on the roof bars.