Rod basics;
6011 is an all purpose rod designed to run on AC.
It is part of the fast freeze group. If you could ever own only one rod size and type, it should be 1/8" 6011.
6011 is appropriate for rusty/dirty/painted metal, filling large gaps if needed and out of position welds
and is far more forgiving and easy to learn than 7018
Run 1/8"6011 at 90 amps on your Lincoln AC buzz box or 80/85 if you have a newer model.
If you are welding thin metal, you can lower the amperage a lot, once you gain some rod controll (at lower heat, it is harder to keep the rod from sticking to the work.
For your machine, you would need 7018 AC, since 7018 is a DC rod. Most profesional welders use 1/8" 7018 for most structural steel work.
7018 is part of the fast fill group. Welding with 7018 requires clean metal and close fitup. Gaps are difficult to fill with 7018, and while it is possible to do so with much technique and practice, it is still not recomended, for metalurgical reasons. (most of the welding instructors I have ever met simply say that gaps cannot be filled with 7018.
As mentioned before, 7018 is a medium carbon, low hydrogen rod with iron powder in the flux for faster higher buildup. Low hydrogen properties will be ENTIRELY lost when 7018 rods are wet or even damp. In fact, 7018 should be stored in a heated rod oven if one expects low hydrogen properties.
7018 is also an all position rod, meaning it can weld flat, horizontal, vertical and overhead. 7018 prefers to weld uphill. Down hill weld with 7018 are absolutely forbidden for anything other than cosmetic work.
For certain metals, 7018 is appropriate, whereas 6011 is not. These are medium carbon metals, such as grader blades, certain cast irons, etc.
It is important to know that welders have and need a code of ethics similar to structural engineers, and undergo much practice and training to safely carry out their art. People can die or be severely injured if weldments fail. At a minimum, you should buy a good book on welding from a reputable publisher. I have read many very poor books on welding and can recommend only two sources though doubtless there are others; Hobart and Lincoln. Both run large schools and teach industry standards which are constantly being revised and reviewed by welding engineers. (I actually have friends in the welding feild who hold doctorates).
I personally have no use for 6013, it is a new metal fab rod, designed for high speed low penetration welding of sheetmetal. It has essentially been made obsolete by MIG welding. If you don' t have a mig welder, it may be an appropriate rod, however it does nothing 6011 will not do a little slower and is subject to slag inclusions, when applied incorrectly.
7014 is similar to 7018 and can be replaced entirely by 7018, with the exception that 7014 can and will run downhill successfully. I see no need to inventory any rods other than 6011, 7018 , stainless steel and a very special and expensive repair rod I use for certain tasks. I commonly stock rods in 3/32 and 1/8 diameters.
Ocasionally I will find a use for 5/32, but usually when I need to put down that much deposit, I am rigging up a MIG or FLUXCORE first.
The very best thing you can do if you really want to weld is to take a class at your local comunity college or vocational high school, though self teaching is possible.
Feel free to PM me with specific questions if you wish, as you get started. Your machine needs a dedicated 50 amp 220 volt circuit breaker. Your cord size will need to be determined by the length. Any competent licensed electrician can tell you what the CODE requires. Good luck, be safe, and don't use less than a shade 10 lens for arc welding or a shade 5 lens for oxy-fuel work, including cutting.