Flux Cored Welding is not a "new" process, being dated back to the 1920's. Instead of having the protective/stabilizing flux on the outside of the wire, as in "stick" rods, it is at the core of the wire. This flux does the same job as do the gases used Gas MIG Welding.
At Weyerhaeuser Timber Company, we periodically built rail-car "car sills". These are the heavy metal frames upon which the railroad boxcar sits. We would use a "pantograph" machine for semi-automatically cutting out parts for the sill. Then we'd weld many of the parts with "jet rod" (7024 type), which is super easy to run on flat welds. The welds looked VERY nice.
For most other welding, we used heavy duty MIG welders. We'd fiddle with "gas" settings & wire speeds till it was just right. Then we'd just go & go till we got to the end of the pieces. We never had to worry about "duty cycle", we just kept going. We could get a LOT done with those MIGS. If you are going to do a LOT of welding, you may want to start with a wire feed welder.
I prefer a flux cored welder because there's no "gas" bottles nor pressure adjusting, nor are there issues with welding outside in the wind. It's a personal decision; gas or flux cored. I would use the recommended setting ranges, running on the "hotter" side just to get the feel and coordination of running beads. An in-expensive, occasional use flux cored machine for the little jobs is fine. For my bigger jobs I go to my stick welder.
More tips and ideas for flux cored welding:
* If you go through eBay to but one, you may want to first go to welding supply shops & see them in person.
* Flux cored welders are mainly for the thinner materials. If you're going to work on cars & the like, you would probably prefer wire feed over stick.
* I've done a lot of sheet-metal work with stick rods, but I needed to use really small rods, plus do a lot of "touch & go" welding, rather then continuous welds.
* One of your first accessories should be a pair of "MIG pliers". They are great for helping you keep your equipment clean & to be able to easily convert to other wire sizes.
* When you install your 1st wire spool, don't mess with bending it around much, or it may break. Re-threading & pulling out any that's already in the guide tube can be a pain.
* Again, use recommended settings, then make adjustments as needed. Some machines are really limited for adjustments, so you may have to experiment with your gun positioning & arc length.
* I'd bet that there are as many variations for adjustments as there are different manufacturers & models. Be patient & keep trying.
Machine Selection:
* This is primarily dependent on your budget, then on exactly what type of welding you'll be doing. If you feel that you might go beyond just doing your own thing, then get the best you can afford.
* The cheaper units are all pretty much the same: for light duty at home projects. The mid-priced ones can get you started in your business, but you'll likely be up-grading as soon as you can afford to.
Flux Cored Troubleshooting:
* Don't let go of the wire end when you're loading a new spool! It may not feed right even if you can get it all un-raveled & fed through.
* If you feel the wire pushing against the bottom of the puddle, turn the speed down or the heat up (or both).
* Try not to keep the nozzle end too close to the puddle. That can make more splatter get into the tip piece.
* When you first start the weld, stay put momentarily to allow the puddle to form & fill the initial crater.
* Uneven feeding? Make sure the wire guide isn't twisted or kinked.
* Can't see an actual puddle? Clean you helmet lens & get closer. If all you're seeing is a bunch of sparks, you're not really seeing what's going on. And again, you need to go at a speed that gives enough time for a puddle to form.
