As said above 7018 is an all position rod with high strength, 6010 and 6011 are a high penetration fast freeze rod they are usually used for root passes on pipe. Cover and cap on pipe use 7018. 7024 Jet rod is primarily used for flat joints , it can be used for horizontal but a little harder to do.7024 is very easy to use ,hold it on the work piece and just drag no need to try and maintain an arc gap as the flux burns off it creates a concave to the electrode thus creating the arc gap. You can literally drag it and close you eyes all you have to do is keep feeding it.1/8" 7018 usually preforms good at 117-120 amps depending on how accurate you machine is, the same 1/8" 7024 requires more amperage 118-125, (more flux on the 7024) Since 7018 and 7024 are low hydrogen rods they must be kept in a warming oven at around 140 -150 F. Thats if the welds are going to be x rayed. for the average hobbyist don't bother. just keep the humidity off of them. A cabinet with a 60 watt light bulb will do the trick in most cases. There are hundreds of welding electrodes on the market, one for every situation and material. Some are electrode positive and some are electrode negative do some research. some materials require post heat while others per-heat, the list goes on and on. for a beginner get some 7018, 7024 ( for flat ), and 6010 or 6011, and you'll be able to stick most things together.Remember 7018, 6010,6011,7024 are electrode positive, work negative. Loads of things to learn about welding, good luck.