Wet buffing technique
Most compounds and polishes should be used so that there is enough product on the surface to maintain a wet film while the product is being worked. The wetness of the product is lubricating the paint as the abrasives abrade the paint and cushion or buffer the abrading action so the abrasives don’t simply scour the finish leaving behind swirls and scratches.
Dry Buffing Technique - Buffing to a dry buff
There are some products on the market where the manufacture recommends buffing the product until it dries. As the product dries you’ll tend to see some dusting as the product residue becomes a powder and the paint will have a hard, dry shine to it.
Although some manufactures recommend this, it’s important to understand what’s taking place at the surface level as you buff to a dry buff. As the product dries, in essence you are losing the lubricating features of the product and as this happens friction and heat will increase. As friction and heat increases, so does the risk of micro-marring the paint or instilling swirls either by the product residue or the pad material and/or a combination of both.
While we trust that the manufacture knows their products best, when we take a close look at what it means to buff on a delicate surface like an automotive clear coat, it doesn’t make sense to run a buffing pad on top of the paint without some kind of wet film to lubricate the paint at the same time. We always recommend that you follow the manufacturer's recommendations and use your own judgment.
Everyone new to buffing wants to be told some easily identifiable sign that they can use to tell when it's time to stop buffing and it's not that simple, so here's an indicator I've always used and taught to others,
Wet film behind your path-of-travel
As you're making a single pass with the polisher, the paint behind the path of travel of the buffer should have a visible wet film on it. If the paint behind the pad is dry and shiny, you've run out of lubrication and you're dry buffing. Turn the polisher off. Wipe the residue off and inspect using a Swirl Finder Light to make sure you didn't dull or mar the paint, you usually won't cause any harm, but pay attention when your running the polisher and don't buff to a dry buff. If you do, you can quickly re-polish that section by cleaning your pad and adding a little fresh product and making a few new section passes.