Did you know bent tubing can be adjusted? Sounds a little wierd, but let's say you're ready to weld on that new Stinger or Winch Hoop, and even though it will work ok as it is, it would be perfect if it had a little less bend in it. The good news is, because metal has "memory", you can take a little of that bend out. The easiest way is to put one end in the receiver hitch of your truck (or your neighbor's truck if your's doesn't have a hitch) and give the other end a good tug. That's usually good for relieving 1-5 degrees of bend, depending on the size of tubing, and degree of bend you're working on as well as how much of a "tug" you give it.

Grinders are a welders best friend.  We like to use 4.5" or 5" angle grinders for most of our fabrication work.  These grinders are cheap enough at Harbor Freight Tools (sometmes less than $10) that we usually have 2 of them set up, one with a grinding disk and one with a flexible sanding pad and an 80 grit sanding disk.  We will do the majority of our grinding with the grinding disk and then finish off with the sanding disk so as to avoid taking off too much material.