Having to prep surfaces for welding, bondo repair, fiberglass repair, bonding, stain, primer and paint is not fun. Even more so if the area is tight or small. Air grinders are perfect for small areas that a bigger grinder maybe to big for such as cylinders or tight corners. They come in strait and angle. Air sanders move in random circles instead of back and forth which allows a bigger space to be covered with the same results as a regular sander. They also use an interface pad that forms to shapes that are not perfectly flat. Both can be had at harbor freight for a good deal. So when buying tools to do some prep work on your farm equipment why not buy something that that you can use on your home to?