I have had this problem for quite a while. I tried hand polishing but the foggy look always seemed to return. Then I recently tried 3M™ Headlight Lens Restoration System for automobile headlights, #39008,
It is a four step process that restores the clarity of yellowed, hazed, or dull car headlight lenses. Kit contains sanding discs and polishing pad with compound. For use with a drill.
WOW...crystal clear! I don't know if it will last, but it sure is nice to be able to see out of the cabin.
I'm interested to hear if it lasts. I used standard car cleaner (brand: Commandant) and a slow turning polishing machine to do my deck hatches. They become smooth and transparent again after 20 minutes of polishing, but after a few months, the old dull matte finish returns.
Michel Capel, Freedom 44 #4 1981 'Alabama Queen', NED8188, cat ketch with wishbones, home port Enkhuizen, the Netherlands, 52*42.238'N 005*18.154'E.
The process Mark used was actually grinding away some of the detiorated plastic (four steps with ever-finer grit to eliminate the scratches caused by the larger grit in the previous step).
Michel was, most likely, "filling" the scratches with the cleaner which "buffed out" to seem to be smooth & transparent, but which reverted pretty much to their original state as the "filler" deteriorated.
If you want to "poor boy" this project, try starting with automotive rubbing compound and a slow foam buffer & ending with baking soda. You can put on some 303 (or anything else you like) after you're done, but what you "see" after the baking soda is "what you get" when the scratches aren't "filled", so you're not "done" until it looks good enough BEFORE the protectant is added.
I never looked at it that way, but you must be right in saying that I probably just filled the scratches. But the compound I used is quite coarse; if you use it on a red car, your cloth gets red right away. Next time I'm going to try Brasso brass polish. I had good and lasting results with clearing up the polycarbonate bowl of a Plastimo pedestal compass.
Michel Capel, Freedom 44 #4 1981 'Alabama Queen', NED8188, cat ketch with wishbones, home port Enkhuizen, the Netherlands, 52*42.238'N 005*18.154'E.
Products designed to make painted surfaces look better aren't designed to "cut", since the paint layers are very thin. The objective is to remove the oxidized layer of "already dead" paint (which your cleaner apparently does) and little or nothing more and to make what's left below "look good" to the eye...at least temporarily.
Rubbing compound isn't designed for "regular use" in cleaning up your car...doing so would leave you with a primer coat showing in short order. It's actually mean for buffing out the final finish, and has mostly fallen by the wayside since enamels have ceased to be the "last coat". It has more "grit" and does cut better.
Gelcoat wears away the same way...and that's why you don't break out the Ajax and scrub the gelcoat every time you clean the boat. "Fantastik" has no grit, but does remove oxidized gelcoat.
Brasso is even less of an abrasive than rubbing compound (and probably less than baking soda). You'll eventually wear through a plated surface by cleaning with Brasso, but it takes awhile. Plating is even thinner than paint, and most definitely thinner than the layer of deteriorated plastic on the surface of your hatches (that's causing the fogging).
You can grind away a LONG time before you run the risk of substantially weakening a plastic hatch. Use whatever it takes, and finish "as fine as you can"...anything less is going to lead to immense frustration.
I have used Brasso polish on my opening portlights for years. Learned about it on the initial Freedom website. Use it once or twice a season. Seems to work well. Hatch covers have crazing or tiny superficial cracks. Am thinking about replacing them.
I bought a product called Scratch Off (Great Lakes Aero Products) which advertises that it is used by small airplanes for their windshields. I have to do it at the beginning of every sailing season (May) and they dullness creeps back in at the end of the sailing season - October. This year I put car wax on the portlights and it has stayed relatively tranparent.
