Cleaning up polycarbonate on my new-to-me hatch

[Tony]

Hey y'all,
I just picked up a used Bomar hatch at a local consignment place for 25 bucks. It's got some scratches in the polycarb, looks like from a deck-brush. It's usable as-is, but I was wondering if there's a good way to polish these out? Is there some whiz-bang technique or am I just looking at a bazillion passes with ever-finer paper?

Thanks!

[Hirilondë]

Depending on the scratch depth you may have to begin and cycle through the sand papers. Even using wet sanding helps towards the finer end of the process. But I like to use Novus Polish at the end.

http://freckleface.com/shopsite_sc/stor ... olish.html

I have taken freshly cut polycarbonate, routed over the edge, sanded from 80 to 1,000 grit wet, then used Novus and the result was a mirror finish round over. It was for a Hinckley hatch. We use it for exactly the reason you are looking into as well.

The stuff works great, but it isn't necessarily a speedy job, you may have to invest some time.

[Quetzalsailor]

I would add to the 'cycle through the sandpapers' that you start with an abrasive whose scratches are is finer than the scratches that you're trying to remove. Starting too fine means that you'll simply be at it longer. Starting too rough means that you'll be fixing what you've made worse, and you'll be at it much longer.

Depending upon your tool collection and your degree of sloth, you could use jewellers rouge and a buffing wheel on the plastic. Here's a site with a nice table of uses and grits: http://www.hobbytool.com/jewelers-rouge.htm

I've been doing a bit of brass polishing lately, a antique gasolier and two old chandeliers. After removing the remains of the lacquer with lacquer thinner, I used 'Barkeepers Friend'. It works quite well but the acid in it is tough on skin. Between these two substances, my hands took two weeks to heal. The Barkeepers Friend is good at tarnish but does not remove much substance. I cleaned up the 'micro-pitted' surfaces with white rouge on the buffing wheel.

[Ceasar Choppy]

Of course if you get lazy, you can always go over it with a coarse grit and leave it. It will look like frosted glass and will give you some privacy. :)

[CharlieJ]

lol- or sandblast it. Our self built front door has a sail set into it using plexiglass. Laura wanted to have it have a frosted look, so I sand blasted it lightly. The plexiglass sun peeping out behind the sail isn't blasted, so it makes a nice contrast.

[Tony]

Gee....uh, thanks, Charlie (I think...) :-)

[Tony]

On a semi-related note, is there any way to tell if the poly is lexan or plexy? I thought I might pick up a scrap piece and practice on it first.

[Hirilondë]

On a semi-related note, is there any way to tell if the poly is lexan or plexy? I thought I might pick up a scrap piece and practice on it first.

Telling them apart is easy. Simply smack the piece with a hammer. If it is polycarbonate it will merely scratch, if it is acrylic it will break.

[Tony]

It's incredible how, uh, HELPFUL y'all are being... :-)

[Hirilondë]

I don't know of any way to tell them apart aside from the test mentioned in my previous post. Both materials cut, sand, polish etc., virtually identically. I was told by our plastics supplier that only acrylic can be polished to a transparent gloss. So I then went out and re-glazed the Hinckley hatch with polycarbonate and polished the rounded over edges of it. So I proved to myself at least that he was wrong. I can see using acrylic for fixed and operable ports if they aren't over large and are shielded some by the opening or frame. But I would hope your hatch is polycarbonate. But if you can't get info on this from the manufacturer, and you are skeptical, then I suggest reglazing it.

[Quetzalsailor]

You can tell these plastics apart by smell, both at a fresh cut and by burning. You'd start at your local plastic shop for samples (to practice on) and continue by nibbling a smidge off your subject material.

Or you could just fugeddiboudit and assume the original manufacturer had it right. A disadvantage of fuggedding is that most of us cannot tell a sundamaged piece of acrylic from a serviceable one. Your local plastic shop technician can tell by the sound it makes when you rap on it.

[Figment]

It's incredible how, uh, HELPFUL y'all are being... :-)

Yep, this place is worth every nickel of the subscription! :D