Welding Tips and Tricks

I know this is the oldest topic on welding , but I have have one more question is there a difference in performance between the two ,comparing them equally on shiny beveled plate. if welding in a nice dry shop, welding heavy stuff together would you use bare wire mig, or self shielded flux core. Because if I was welding on nice shiny 3/8 plate I would use 75/25 mig. I'm sure all you guys have all got an opinion , lets here it thanks, John

I'm biased as in the UK all the self shielded flux core I've ever tried was complete crap - I hate the stuff ! but I believe in the US of A they have much better quality wire ( ? ) it's a process I would use only out of desperation - I did some repair patches on the deck of a tug I work on as it was so thin in places stick weld just blew through it - it wanted the whole deck re-plating - but at the time the owner did'nt want to go this far - it worked OK for this - needed extensive clean up of smoke / splatter / slag but left solid metal so it got the job done - if I could get a job inside I would ALWAYS use solid gas shielded wire.

Gas shielded / dual shield core wire is a different animal completely - depending on having appropriate wire feeder & good quality wire this can leave clean great looking welds and when you need large welds it has terrific deposition rates - there are also some very good hard facing wires around.

obviously this is just my experience & others will disagree - but I'd liken it to using 6013 - you guys hate on it yet here it's common place - whereas over here I never heard of using flux core for anything that mattered it's generally considered a joke used by non welding types with horrible freight 90amp class machines.

Bottom line if you got clean 3/8" material indoors use solid C75 ( unless in the UK then it's 80 / 20 )

I will disagree with noddybrian.

Flux core wire is used in structural, multipass, heavy metal welding. It is no more dirty than stick welding and much faster.

Heavy industry and heavy equipment welders use it every day. If you think flux core is a joke, you are mistaken or misinformed.

Personally I would not use it below 1/8" steel do to it's slightly deeper penetration than solid wire - but some do.

Indoors I use solid wire. Because of the cost of flux core, I generally use stick outside since I don't need the higher deposit speeds.

I have no real complaints with 6013 either, it's fine for general use, but it's low ductility needs to be kept in mind.

Well at least we got some response to the original post !

Maybe we're not talking about the same thing here - almost all self shielded wire here is low quality 0.8 or 0.9mm used for hobby stuff - I almost want to send you some to see how bad it is ! - yes some industrial places use a form of flux core on heavy material - but this is not strictly in Mig territory - it's generally 2 or 2.5mm ( sometimes bigger ) wire fed by a dedicated feeder ( fricking huge thing generally with a boom arm to carry the very heavy cable / torch ) and maybe self shielded but often is run with gas - depends on the wire and application - but if you go into any fab shop around here including ones that build bridge structures and heavy beams etc you will find only solid wire - generally 1.2 > 1.6mm diameters - on big production runs of heavily welded pieces submerged arc is quite common - about the only place I've seen much large flux core is shipyards and even that seems to be on the decrease.

I think though there is a great divide across the pond on many aspects of welding -

Here is one to look for that I've used and can recommend from lincoln.
http://www.lincolnelectric.com/assets/g ... 200010.pdf

It's the E71T-11, for general use.

(I fixed the link)

Elsewhere in this forum I have quoted people who claim, by volume of wire sold, the use of flux core wire is increasing, particularly in heavy duty applications, and, more particularly, in ship building.

I have seen ship building in China, and, yes, the machines were the large separate wire feeder units, but I asked and was assured the processes used was flux core, (and they were mightily amused that I should ask: not sure what that was about). The big welders didn't even look like welders, more like farm equipment. (Incidentally, China has built ten of the twenty longest bridges in the world, all in the last ten years: they know a thing or two about this kind of engineering and fabrication. You've got to admire their work.)

In the small shop, apart from the cost of the wire, and the appearance of the weld and surrounding surface (I have a good array of slag scrapers!), why wouldn't you use FCAW-ss? With experience, the weld bead looks OK, (not as good as MIG, and certainly not as good as TIG), and the client doesn't care, particularly on steel that is going to be primed and painted, and covered by mesh, or timber, or sheet steel or plate? But, with an even weave pattern, it looks fine, after you clean off the slag.

And you can weld hot, right down to 1mm steel, even less with care (again, it is not the best here, but the welds don't break).

Having said that, I don't know anyone else who depends on FCAW as I do in my light work context.

AnvilJack wrote: In the small shop, apart from the cost of the wire, and the appearance of the weld and surrounding surface (I have a good array of slag scrapers!), why wouldn't you use FCAW-ss?

I think you answered your own question

i've used self shielded wire on many high rises here in nyc and so far their still standing. it's fast, has great penetration, passes ut inspection and if i say so myself looks great.

The cost difference may not matter, too much, depending on circumstances. Costs always matter, in business, but if you don't have to lease a gas bottle, drive to get it and refill, etc, and you can move your gear quickly (or not, because you also have to take the gas), the costs might be pretty similar for MIG v FCAW.

No-one, client of welder, has commented adversely on the appearance of my FCAW beads. I do have to clean the welds and surrounding metal, but I am sure everyone who gets into light fabrication (as I am) will achieve acceptable weld appearance. And if something goes wrong, grind it off a bit. I've done this once or twice, literally. Of course, if your work is a join in a dynamic surface, you will grind it smooth any way, to avoid the risk of metal fracture alongside the weld. You should expect welds of OK appearance with FCAW.

What I gain from using, almost exclusively, FCAW, is a confident approach to outdoor work in many conditions with portable equipment, and (lately) a "standard" wire size and type that I know will work.

Now, I am sure, other people do the same range of work and use MIG, and are equally happy. (Until it is very breezy, or their gas won't reach the last three steps, etc -- but all of this can be managed, I know.)

My main point is, nothing prohibits a capable person from using FCAW in fabrication, in the shop, or in the field.

AnvilJack wrote: My main point is, nothing prohibits a capable person from using FCAW in fabrication, in the shop, or in the field.

No argument with that.

I just prefer solid wire indoors - and naturally prefer to weld indoors (winter is long here).

I do not have enough make-up heat capacity to ventilate like I do in the summer - so hard wire is great for my uses

i remember seeing dual shield mig for the first time while working on an office tower about 35 years ago. i had never seen this process before but was knowledgeable in solid wire mig and innershield so it was no big deal to get the hang of it. the erection company sent out backing bars for the 100% penetration welds but they were only 1/8" thick and the first pass was blowing right through the back up bar so they had to switch to 1/4". i don't remember the wind giving us many problems with the shielding gas although once or twice i had the apprentice boy hold a small piece of plywood to protect the gas shield. the next job was right on the east river with the usual awful conditions on open steel coming into the winter. on that job we were using straight innershield on the column splices which was a smart choice given the windy conditions.

I personally run flux shield in my welder just because I weld a lot of dirty metal and weld a lot outside too so that is why I still run it. When I got the welder I didn't have enough money to buy the welder and get shielding gas and wire so I got a spoil of flux core. If I had the money now I would hook up shielding gas in the summer cause the shop we have now has no ventilation other than a box fan and the cracks in the wall. As far as weld strength I have done a lot of welding on our old tractor and none of them have broke yet, and trust me my father in law is the hardest person on equipment. Thats just my opinion take it for what its worth.
Matt