Griot's Garage 6", Speed 4.5, primed pad, enough pressure to keep the pad down flat without it stopping rotation. I was using one of the safe bug scrub sponges in between passes to clean the pads.
That all sounds good. There are lots of ways to make things work. Since you said the scratches didn't all come out, and
based upon what you've told us... you may be:
1. Working on hard paint (not as big an issue as most guys make it out to be).
2. Moving the machine too fast.
3. Using too high of a speed.
4. Doing everything right to this point.
Add this to your process:
After you've primed the pad and applied product, polish the area (18" x 36", or whatever size iswithin arms reach). Move the machine about an inch per second. If the backing plate is spinning really fast, drop the speed a little. Apply a decent amount of pressure, and maybe adjust pressure and speed so you see 2-4 turns per second of the backing plate.
Once it looks as though the polish is starting to dry, or the surface is relatively free of compound, mist the area you've just polished with a spritz of water, and re-polish. No need to add more product. You'll probably get about 30% more cut, and you should be able to polish 2-3 times longer without adding more product by spritzing one or two more times.
The water loosens the particles and redistributes them.
The water also keeps the microfiber strings from packing tightly against each other.
Watch the speed, adjust your pressure, and use a water spritz.
Let us know what you come up with.
Oh!- If you've got some time, start reading this:
KBM - Pad Priming and Supplemental Wetting Agents
Look at the info on page 30, titled:
Water Spritzing... the Nitrous of Paint Polishing?