Decoding Welding Rods

General Information
Amps = Heat Smaller Diameter Rods Burn "Hotter"
Volts = Force (penetration) Larger Diameter Rods Burn "Cooler"

General Welding, DC Current
6011Burns through crud1st. Choice For Field Emergency Repair
(commonly refered to as a 'Farmers' rod)
6013Burns WellOverhead2nd. Choice For Field Emergency Repair
5-P or 6010Direct Current OnlySuitable for use with On Board Welder Projects
Let's start by decoding the short one.
If you have digits left over, it's a long number, read on.

"E 6011" This can be decoded fairly easily.

"E" stands for "Electrode"

The first two digits (or first 3 if it's a 5-digit number) are an abbreviation of the weld's strength.
To figure out the strength of the weld, take the 2 digits, in this case 60, and multiply by 1000 to get the weld strength in PSI. (60,000 PSI)
In this case, 'E 6011' is 'Electrode', '60xx' is 60,000 PSI weld strength.

So if you had welded two plates together, with the weld covering one square inch (or even 1/4" x 4" : that's still one square inch) that weld could take 60,000 pounts of pulling force.
Typical vales are 60, 70, 80, 90, 100, 110.
(Example: 'E 10011' would be, 'E= Electrode, 100xx= 100,000 PSI weld strength)

The 3rd digit (or fouth on five digit numbers) tells you what position the rod is recommended for.

xx1x: Flat, Horizontal, Vertical, Overhead.
xx2x: Flat and Horizontal only.
xx3x: Flat, Horizontal, Vertical Down, Overhead.

(Example: 'E 6011', 'E'= Electrode, '60xx'= 60,000 PSI weld strength, 'xx1x'= recommended for flat, horizontal, vertical, overhead)

The last digit tells you about welding current and the coating.

xxx1 : DC:ROD+ cellulose sodium
xxx2 : AC or DC:ROD+ or DC:ROD- cellulose potassium
xxx3 : AC or DC:ROD- titania sodium
xxx4 : AC or DC:ROD- or DC:ROD+ iron powder titania
xxx5 : DC:ROD+ low hydrogen sodium
xxx6 : AC or DC:ROD+ low hydrogen potassium
xxx7 : AC or DC:ROD+ or DC:ROD- iron powder iron oxide
xxx8 : AC or DC:ROD+ iron powder low hydrogen

You probably don't need to worry much about the coating.
I have in my notes, but don't remeber where I read it, that having the rod + will give deeper penetration, and the rod - will give faster deposition.

If there is a letter and number combination next, it relates to the chemical composition of the weld deposit.

B10.50%Cr  0.5%Mo
D10.25-0.45%Mo  1.25-2%Mn
G*0.5%Ni>0.3%Cr>0.2%Mo >0.1%V  
* (G only needs one of the elements listed)

Next part is a H#. This relates to the maximum amount of hydrogen that will be diffused from the rod. A trailing R means that the rod is moisture resistant.