A few things that I have learned about polishing over the years that I would like to pass on are the following.
A lot of parts, cast and machined can be filled to finish shape. Think of file as the “starting grit” of polishing. I generally finish with #4 then #6 cut files.
Cleanliness, clean up the immediate area and backing blocks when changing to finer grit.
A lot of “polished” work one sees is generally poorly done, not so much for lack of skill but lack of what to look for. One generally sees lots of fine scratches in a highly bright parts...it is easy to miss seeing a 360 grit scratch when working with 400 grit paper. By the time you get to 500 or 600 grit paper you start to see the 360 grit scratches, then, if you want to remove the 360 grit scratch you need to go back to the 400 paper. The way to avoid this is to vary the angle of your polishing strokes. As an example on a lock plate, that is in good shape overall, let’s say you are starting out with 220 grit paper that is backed with a piece of wood shaped at one end so it will not dig into your palm, the other with an angled flat sanded or filed on it. Start diagonally polishing on the plate and vary stroking from 45* +or- one way then 45* +or- the other way. When finished with the 45* polishing, polish fore and aft until all of the 45* marks are removed. Look close for the 45* marks then look closer. Your personal level of OCD will tell you when it’s “good enough “. Then clean up and start with the next finest grit, alternating with 45* strokes until all of the fore and aft marks from the previous grit is gone. Look close! Use this technique of finer and fine grits till you reach the level of polish you desire.
It is false economy to try and save paper by using it to “death” , develop a feel for what the new paper feels like when it starts to cut, when you don’t feel it cutting any longer, cut a new piece or re-position it.
Use thin “rubber” gloves and use some lubricating oil like , diesel fuel, kerosene or a commercial product that companies sell....try Gesswein.
Clean up well when going to finer grits.
For some curved surfaces you can glue a thin hard rubber back to your sanding block. By block I mean any shape that you may want to use to back up your paper. There is a fellow here that admits in the wee dark hours of early morning he uses his fingers as a sanding block. He know the importance of sanding blocks...don’t use them then and you will get seasick from the waves and whoop-de-doos from a “flat” plate.
Then there are polishing stones....
And as Bob Roller said....It’s a learning process so enjoy the ride.
Cheers Richard
