Picked up a nice acrylic tank and it has one decent scratch I'd like to buff out and of course some smaller ones that should be buffed before filling. I'm worried I'll butcher the tank. What have you done with moderate success?
I've been using the Novus 1, 2, 3 hand polishing system with decent success on my 8 gallon nano reef. If it is a very deep scratch, you'll will need some fine grade sanding paper first to get rid of the scratch. There are a bunch of Youtube videos available on using Novus which I found extremely helpful. Hope that helps!
Scratches you can feel with a finger nail need to be sanded out, you'll want to use micro mesh sandpaper starting with 1500 grit and working your way up to 12000 grit. Go slow and light pressure, letting the sandpaper do the work. Sand an area a few inches in each direction so you don't get a divot. When you're finished the acrylic will still have a slight haze to it, don't panic as the next step will polish the acrylic to almost new clarity.
Once finished and for minor surface scratches use Novus polish from 3 to 1, use an acrylic cloth or polishing wheel as anything else may leave surface scratches. Since the tank is empty polish the entire tank with all 3 Novus polishes, once done you'll be hard pressed to tell the tanks used.