Mirror Aluminum Finishes

I am building a couple 6" refractors, and I would like some mirror-like parts on them. (See Pic) As I understand it, I could:

(1) chrome them, or
(2) nickel plate them, or
(3) highly polish them and clearcoat, or
(4) highly polish them and not clearcoat, maintaining the shine instead.

Can anyone speak to the practicality of any of these paths? Path 4 seems pretty attractive if the shine can be maintained.

Attached Image:

Mike

What type of metal are you working with?

Dominic DiLeo

If you highly polish them you will always be keeping up the shine. Mothers aluminum polish works very well, but it would be easier to clearcoat.
The problem with chrome is it will peel from aluminum some times and is a costly process.
A brushed finish looks very nice to and needs little maintenance and can also be clearcoated with good results.
Floyd

Back in the '50's & '60's, it was well known that aluminum as a mirror coating oxidized in the presence of air to form an extremly thin, clear, protective AlO coating that didn't alter over time. The use of a hard SiO overcoat merely added further protection against sleaks, but was/is not neccesary to preserve the reflective surface. Dudley Leroy Clausing added berillium to aluminum to give it resistance to sleaks and his Beral mirror coatings were not overcoated (mine has survived decades). All the parts on my 6" reflector, including tube, are of either aluminum or brass, left *natural* with no clear overcoat. I removed the paint on focusers, etc. and buffed. Ocasionally I use Brasso on the brass focuser tubing, but for the most part leave alone. This scope has survived decades of outdoor extremes with no corrosion, and looks as good as the day I made it. Granted, except for the brass, my finish is satin but still you may wish to give your option #4 a try, and can always do further treatment later if not satisfactory.