I can't speak for all parts of the country, but around here unless you can round up some companies or oil field work to carry you along you're most likely going to have a tuff go of it fixing farm equipment as anything but a hobby. And that usually means insurance, high insurance.
I got completely away from welding altogther after my back messed up, but in the 30yrs I did fabrication, both in what I did for myself or for shops that I worked or contracted for, a lot of work of this nature was considered secondary and done more for good will then anything else.
Equipment, rods, gas, grinders, abrasive wheels, tools and materials get expensive quick and things need to be constantly replaced. it also really takes a pretty good stock pile of angle, flatbar, pipe and plate lying around or at least a good source. Warning: Some Wives tend to frown on these items strowed about in the front yard too. Usually when something breaks on farm equipment it's worn down, stress cracked or fractured and bent to heck and the section needs to replaced and strengthend. If you have mills that material can be found at cheap that would be a big plus. Company auctions are also a good place to look for equipment along, it would help to have some idea what is being sold before hand so you don't end up with stuff you cant use or 3 phase in a home shop. Machine work is also a frequent requirement so knowing a machinest with a little free time could be in your favor.
Here most people with equipment that can afford to fix it at your realistic costs and show a profit probably have a welding machine, know someone with one or carry it to a machine/ fab shop or dealer to have it repaired. Any more premanufactured implements are often hard to compete with unless specialized or a good source of steel is available. Some casts and alloy applications also require different methods to repair and it isn't impossible to make matters worse if not done correctly. Take a guess who will be expected to eat that and that's also when the price rate usually soars. So some good knowledge is needed on metals and it's good to have a good reference source availiable. Getting a good buisness going will depend on several factors worth checking into before jumping into it head first.
