Re: Rub rail trim?
In your case, you are probably not going to be removing much of anything...it would be best to mask off the rubber insert, if you plan to leave it in there, with at least 3-4 layers of masking tape or 2 layers of duct tape...and do the same to the hull above and below...
If anything you can work on a section at a time...in other words just mask the area you plan to do...
Also, being that you are working on the boat, it would be best to do it all by hand...unless you have a lot of practice using a D/A, I would advise against it, because you could slip and cause damage to the hull...or the rubber insert...
If you have any deep scratches, you might have to start with something as coarse as 40-60 grit paper and work your way up to 800-1200 grit until you get rid of the previous grits scratches...
Once you get to the final grit...you can apply some Mother's and buff it out...if it still won't shine the way you want, go to a finer grit...by the time you get to 1200-1500 grit, you should be almost polishing the rail...
Be sure to use wet paper for the finer grits, 600 and up and add some dish detergent to your water and rinse often...
You can get a High Polish if you take your time and you should be able to avoid spending the big bucks for new rail by using some of that free elbow grease...
Have fun and post up some close up pics of your project as you work through it...
GT1M
PS- here is a slightly better video of the process I used to polish my rub rail using a D/A and Mother's...
https://www.youtube.com/watch?v=b81XyMwfqq4