A roll of flux core 309l wire should be arriving in today's mail . I'll soon know if it will be the solution to my project . I hope it is , I'm a much better MIG welder than TIG . I've been practicing on scrap exhaust pipe , mild steel and a little SS , and it looks better . But nobody would actually pay for welds that look like mine ... ah well , pretty is secondary , strength and corrosion resistance are my primary concerns .
That sounds interesting.
Will you switch the polarity like regular gasless flux core steel wire?
Or... Will you run dual shield?
I was running gasless flux core one day and the welds were going like shit. I had specifically said I was running gasless, and one of the morons I was helping turned on the gas when I wasn't looking. The gas was blowing away the flux smoke. I spent a stupid amount of time grinding and re-welding.
I only noticed it later because I have a habit of checking the gas bottles when I walk by. I gave it a light twist, and it moved.
A roll of flux core 309l wire should be arriving in today's mail . I'll soon know if it will be the solution to my project . I hope it is , I'm a much better MIG welder than TIG . I've been practicing on scrap exhaust pipe , mild steel and a little SS , and it looks better . But nobody would actually pay for welds that look like mine ... ah well , pretty is secondary , strength and corrosion resistance are my primary concerns .
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I still don't know why my MIG sheet metal welds suddenly changed from a mess of blobs to a smooth even flow with the right penetration. I stopped practicing and did the fender repairs before losing it.
Possibly the change was from using up the more oxidized wire on the outer layer of the large spool.
That is a possibility . I put a strip of scotchbrite pad - folded so the wire has to run thru several layers - on the MIG wire before it goes into the drive wheel assembly . Cleans the wire some I guess . Bob , I'm going to try it both polarities . I'll start with the electrode negative like I do with flux core mild steel , if it looks good I won't try 'trode positive . If not ... I was going to try it out this afternoon . After listening to my wife cuss out her sewing machine (65 yrs old , from her granny) several times this morning I told her it was time for a new one . A 120+ mile round trip and 400 bucks later ... but that was OK . I needed to resupply the likker cabinet , and I patronize a store in that same town . Cheaper than the one just across the county line , enough it pays for my gas !
Just what everyone needs; "helpful" people!
Never used gasless - however read about.
It says, and makes complete sense to me as a metallurgist / scientist...
Never use shielding gas with gasless.
The system works because the composition of the atmosphere is known and just the right amount of deoxidisers and denitriders are in the wire.
As the atmosphere has the same composition across the world, the result is, when otherwise used right, end up with the right weld metal.
Surround gasless wire with a shielding gas and you do not get the right weld metal.
Never use shielding gas with gasless.
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I bought a used Powermate Tote-Mig that was permanently wired electrode-negative, similar to this:
It was OK with flux-core but not with bare wire and CO2 for auto body, so I added terminal bolts to swap polarity, then I got some good welds from it and the night school instructor got great ones in up to 3/16" steel. Since he had proven that it worked and I'd paid for the supplies I did the rest of my practicing on the school's Miller.
Why would an older MIG have a gas solenoid but flux-core polarity?
Never use shielding gas with gasless.
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Why would an older MIG have a gas solenoid but flux-core polarity?
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This appears to be the answer:
The Miller 212 (my best machine arguably) is easily switched with lugs by the wire feed inside the cabinet. Nothing else changes when you swap the cables. Always fires the associated solenoid when you pull the trigger on one of the guns. I expect they figured most folks would only run GMAW, and never FCAW with it, but the capability is there.
I ran FCAW for years because GMAW just didn't work on my steel stinger. Since I'm not a real welder or even a real fabricator it took me years before I discovered the problem. The gas diffuser in the stinger had no holes. (It came that way directly from Miller.) I did have a gas bottle sitting there, but it went many years without even cracking the valve.
P.S. I find (maybe its due to grater experience with it) that FCAW is much easier for out of position welding. Even overhead.
P.P.S. When I posted pictures of the gasless gas diffuser on Miller's web forums they sent me a whole box of consumables including a couple proper gas diffusers WITH HOLES.
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