I use one professionally on car paint - for compounding after flatting back following repainting.
Mine is heavy, not random orbit & corded - a battery powered one would be of no use for my purposes.
You MUST keep it moving & follow the instructions on the polish/compound you are using. Water is often used as a lubricant & a hand spray of the B&Q bottle type for misting plants works well.
If you stay too long in one spot heat build-up due to friction is rapid & a lot of damage can happen very quickly - guess how I found that one out.
Bear in mind that compounds and most polishes are abrasive - compounds are available in several grades of cut - so each time you use it you are removing material & the firmer the mop the more it will remove.
Compounding & polishing mops are most commonly available in 150mm (6") diameter & I prefer those that come with a plastic backer glued on. Thread size M14.
To do the hull of my boat I use Farecla G10 on a medium mop for cleaning & a wax polish for final shine by hand with microfibre cloths
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