Wool pads cut faster and generate less heat than foam cutting pads. IMO they tend to be easier to use too. They are great for when you have a car with extreme cob-webbing, holograms and RIDS, or when wet-sanding. The down side is that they also leave behind deeper swirls than foam pads, and usually need 2-3 more following buffing steps to finish off.
Of course you always want to use the least aggressive method for the job, but wool pads should be in every detailer’s arsenal.
rops:
Really well said.
Think of your buffing pads as tools in a tool chest. Sometimes you'll want and need a very specific pad
or tool for a specific job.
Let me use the mechanics tool chest for an analogy. If you're trying to remove a head off a big block chevy, you're going to want to use a 6 point socket, not a 12 point socket to remove the head bolts. A 12 point might work but you don't want to risk stripping the head of the bolt so a 6 point socket will provide maximum grip.
If you're removing sanding marks out of paint, a foam pad will work but like Rasky said, you'll tend to generate more heat; this doesn't mean you can't remove the sanding marks but you don't want to make a mistake by overheating the paint so a wool pad will not only cut faster, but they will tend to enable you to buff a section without generating as much heat.
The heat differences is caused by the contact surface area of the pad. Generally speaking you hold a foam cutting pad flat to the surface so the entire surface area of the face of the pad is creating friction.
With a wool pad, you can still hold it flat to the surface but not everyone does as it's a natural tendency to buff using just a side of the pad, less full contact buffing taking place. Don't get me wrong, you can overheat paint just as easy with a wool pad as you can a foam cutting pad but generally speaking, if you're cutting with a wool pad you'll generate less heat than if you're buffing with a foam cutting pad.
There's some more dynamics involved concerning individual fibers versus a uniform even continuous one-piece material but I think you get the point.
If I had to sand and cut a finish, for my first cut I would use the most aggressive wool pad money could buy.
