Polishing Plastics

[Tin Falcon]

As many of you know I tend to build my engines of unusual materials. Unusual for engines anyway. Several are see through and made of Lucite and several are of Corian. In order to see through Lucite it needs to be glass clear.
A common question I get is "How do you polish it?
Looking at my life I have probably spent more time shaping and finishing materials with sand paper than with machine tools. Sanding can be an art feel , practice and a trained eye can effect the outcome.
Hear are the basic steps to polishing Lucite. Wet sand with 320 grit silicon carbide paper. then go to 400 grit and finally 600. I then polish (Twice) with No7 brand white polishing compound from the auto parts store then finish with a couple rounds of Mothers Brand Plastic Polish.
Hobby shops and auto supplies sell higher grit paper and I there are other product that will give good results but this works for me. Cheap plastic polish from the auto parts store does not work I tried some brown stuff one time, white seems to work better.
Tin

 

[Cedge]

Tin
With the results you get with 600 grit and compound, you'd love the 1200, 1500, 2500 and 4 micron stuff that @M offers. I've not found a source yet, but I'm always looking for a place to get a box of 4000 and 6000 grit.

I found a product a while back that is closest to being a universal metal polish that I've seen. The product is called MAAS and is good enough that the US Navy has approved it to replace Brasso. It has a bit of microscopic grit suspended in a paste, Once you have the metal fine finished with sand paper, it can take it on to mirror level. Ace Hardware and Walmart supermarkets carry it in stock.

I've polished everything from plastic, steel, cast iron, aluminum, stainless, copper, brass and bronze. I like it better than SimiChrome or Flitz. It's a non etching product which means it will never leave you with a drip mark burned into the metal the way Brasso or other acidic polishes can. It also leaves a light proctective coating that helps keep rust and tarnish at bay.

Steve

 

[GeorgeGreek]

Hi Tim,

when making lenses from Lucite, after the 1500 grit, I continued with a brass cleaner (regretfully not available anymore) and finished with toilet paper and toothpaste ( different brands have different "grit" ) and the finish was excellent.

George