I looked for some tips on overhead welding. Some say the contact tip should extend a little beyond the nozzle either by cutting the nozzle down or getting a longer tip. Does anyone do this? Seems like it might help to keep globs building up in the nozzle?
I'd stick with nozzle and tip flush. Tho T here's not much information in your post to give advice. Like material thickness gap weave or stringers. But what i would say is if its a weave you may find ir runs best if you're on an off the trigger as in a pulse. three seconds left and three right with a one second delay in the middle.
Get some flux core wire try that. Or as one weld tester told me year ago set it the same as down hand and you be fine, this hardly ever fail me.
Practice
Toms got it
and lots of it!!!
Keep the nozzle cleaned out and use Nozzle Spray. As others have stated, time will teach you how to do it without making a big mess with the nozzle, but you will still get some stuff in there, keep it cleaned out.
12ga to 1/2". Mild steel to grade 80. 100% CO2, flux core. Usually Excel Arc 71, Just trying out Radnor McKay speed alloy 71A. I can weld a fairly decent bead but what bugs me is globs of weld in the nozzle. The tip has always been about 3/16ths below the nozzle since I "inherited" it. Maybe I should change that? Practice? Hell, every single bead is practice, learn something every time.
Rob, if you're getting big gobs in the nozzle, a number of things can cause that. Just to name a few, heat too high, moving too slow, nozzle/wire pointed/angled toward weld being laid down. Angle the nozzle/wire slightly away from the weld, in the direction your welding. And move, don't get the weld so hot that it falls down in balls.
Wait, what? 100% CO2, that's part of your problem. 100% CO2 makes a hotter weld, for deeper penetration, but a drawback in overhead. IMHO, you'd be better off with Argon mix.
Thanks Willie, that's good to know.
And the more molten metal up there the untidier it will be.Start off with small diameter wire and as your skill increases you can start pumping it up.
If you're running flux core wire there's no need for any gas at all. Depending on what welder you've got, if you're not running gas, they make tip covers that almost touch the tip, that would help keep stuff off of it.
There are a few types of flux cored MIG wire. Some are self shielding and don't need gas. These are used wire to Negative on the welder. The other is outer shield which does need gas. Its run wire positive as is solid wire.
Both Exel Arc 71 and McKay Speed Speed Alloy 71A are gas shield flux core wires, they use shield gas along with the flux core. But try the 75/25 Argon mix, I think you'll see a big difference.
Well, I do learn something new everyday. But, I can't figure why you'd want to buy a flux core that needs a shielding gas. If you're going to go that route why not just run solid? I've only ever used the innershield flux, never needed gas, makes life so much easier when working outside.
That's the thing about welding materials 95, all sorts of product for all sorts of applications, one just needs to fit the proper product to the proper application. The local welding supplier should be able to fit the need with the proper material.
As to why flux and gas both: the flux has refractory and other ingredients pertaining to the weld quality and is not able to achieve that without also adding the gas; it takes both items to accomplish the weld. I have been told not to only consider the flux for 'shielding from the atmosphere' as it does other functions as well.
Try it just once on an appropriate weldment, and you will understand. Don't remember the specific wire we used, but provided a beautiful weld-smooth bead, great profile in most positions, little slag to chip as most just rolled off, superb penetration. Hot, smooth, quiet, strong.
I used to do a lot of spray arc with bare wire, it's only good for flat or nearly so welding... dual shield, gas with flux cored wire, is like spray arc for all positions, assuming you're using an all position wire of course. First time I ever ran big Miller with dual shield I wanted to marry it.....
Which is understandable...big blue don't nag like the other marrying partner.
My tip was down 3/16 from the nozzle. Shortened the nozzle so there was only 1/16. Appears to have worked, not getting globs anymore.