Re: Polishing Lexan or Plexiglass

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Steve Cook by way of Terry Fritz <teslalist-at-qwest-dot-net>" <steve-at-g8cyerichmond.freeserve.co.uk>

Years ago I used to use a mix of soap and cerium oxide for the final polish
on perspex (plexiglas) museum specimens. You can get cerium oxide from
gemmology stores as jewellers rouge, simply make a paste of shredded soap
(very little) lots of cerium oxide by volume and enough water to make it
like a toothpaste constituency, make sure you use a clean!!!! lint free
cloth for the polishing, it can also be used on a felt wheel polishing disk.
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, April 09, 2003 8:07 PM
Subject: Re: Polishing Lexan or Plexiglass


 > Original poster: "Jim Lux by way of Terry Fritz <teslalist-at-qwest-dot-net>"
<jimlux-at-earthlink-dot-net>
 >
 > Polishing edges to get that glassy clear look:
 >
 > 1) Make sure it's reasonably smooth.. sandpaper on a block or a fine file,
 > or a belt sander
 > 2) scrape the edge with a razor blade.  the sharp edge of the blade should
 > be at right angles to the direction of scrape (along the edge), and the
 > blade should be almost at right angles to the surface being scraped.  When
 > you are done, the edge should have a "frosted" or translucent appearance
 > that is quite uniform. (It's very different from the sanded look).  If you
 > stick your greasy thumb on it, you should clearly see the fingerprint.
 > 3) Carefully! fire polish it with a propane torch .  This takes a bit of
 > practice to get the distance of the torch right and the time of heating
 > right, but if you've got the scraped surface, it takes a second or two for
 > the frosted surface to melt and go perfectly clear.  I've found that you
 > want to keep the flame several inches away, so it's just the hot
combustion
 > gases hitting the plastic.  Keep the torch moving!
 > 4) If you need more polish than that, you can get plastic polish (which is
a
 > very fine abrasive much like jeweler's rouge...) and go to town.  Aircraft
 > supply places carry it to polish aircraft windshields and windows, where
 > you're always trying to get rid of those horrible scratch marks that make
it
 > hard to see when you're flying into the sun.
 >
 > This is definitely something where a few hours of practice is needed.  Hie
 > thee on down to the plastic scrap bin and get scraps of a)the same kind of
 > plastic! and b) the same thickness of slab.  You'll need a whole package
of
 > single edge razor blades too.
 >
 > ----- Original Message -----
 > From: "Tesla list" <tesla-at-pupman-dot-com>
 > To: <tesla-at-pupman-dot-com>
 > Sent: Tuesday, April 08, 2003 7:27 PM
 > Subject: Polishing Lexan or Plexiglass
 >
 >
 >  > Original poster: "Mark Broker by way of Terry Fritz
<teslalist-at-qwest-dot-net>"
 > <mbroker-at-thegeekgroup-dot-org>
 >  >
 >  > After much thinking and internal debate, I decided to make my next TC
 >  > primary base out of 1/2" thick Lexan and the primary winding supports
out
 >  > of 1/4" lexan.  The base will be 18" in diameter, there will be 6
radial
 >  > supports for the primary winding (about 13 turns of 3/16" copper
tubing).
 >  > (3.5"x 18" secondary with 28AWG, 12/60 input, sync triggered gap,
GeekCap,
 >  > FWIW)  I'm wondering if there is any way to polish the edges to
 >  > reduce/remove machining marks from the Lexan.  I have only attempted
fire
 >  > polishing with a blow torch once, and the results were abysmal. :/
 >  >
 >  > Thanks,
 >  >
 >  > Mark Broker
 >  > Chief Engineer, The Geek Group
 >  >
 >  >
 >  >
 >
 >
 >