RE: [TCML] Polishing Lexan (small, recessed areas)

["McCauley, Daniel H" <daniel.h.mccauley@xxxxxxxx>]

Thanks Jim and others for your comments.
I'll definitely try the flame method on some scrap materials and see how
that works!

Dan
 


Daniel McCauley
Transmitter / High Voltage Engineer
Lockheed Martin MS2
Mailstop 142-1
199 Borton Landing Road
Moorestown, NJ 08057
(856) 722-2387
daniel.h.mccauley@xxxxxxxx


-----Original Message-----
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
Behalf Of Jim Lux
Sent: Wednesday, March 05, 2008 4:23 PM
To: Tesla Coil Mailing List
Subject: Re: [TCML] Polishing Lexan (small, recessed areas)

McCauley, Daniel H wrote:
> Need some expert opinions on polishing lexan.
> Basically, i'm looking to polish small recessed pockets that have been

> machined into blocks of lexan.  For example, a 2"x2" pocket, 0.5"
deep.

How smooth?  glass like surface?

Scrape with a razor blade held perpendicular to the surface.
Flame polish with a propane torch or a low speed heat gun.

Practice on a scrap.  It sounds hard and risky, but 20 minutes of
playing around will teach you all you need to know to do it right
without screwing up the workpiece.

Polycarbonate is nice for flame polishing too, because it has a real
characteristic smell well before it catches fire so you can pull the
flame off and blow cool air or plunge it into a bucket of water.

But really.. it's not as hard as it seems.  Go slow and keep the torch a
fair distance away. What you're looking for is a fairly gentle, but hot,
stream of air.

Those little butane torches are very hard to control in this kind of
application (too much heat in too small an area).  The regular old
Bernz-o-matic like you'd use for sweating copper pipe fittings is what
you want.



> 
> Not too keen about flame polishing, especially on a part that will 
> take a long time to machine.  Although i have read that MEK solvent is

> something frequently used or a plastic polishing compound such as
NOVUS.

The problem with grit polishing is that you need to have something to
move the grit with, and it's awfully easy to push too hard in one place
and make a depression.  Polycarbonate is tough but very soft.  It's also
hard to get a good polish in inside corners.

if you know a place that does abrasive polishing with the mud like
compound under pressure, that might work.  It's used a lot on things
like intake and exhaust manifolds.  The problem will be whether they can
work with plastics and whether they'll have the process controls figured
out.


> 
> Any thoughts?
> Thanks
> 
> Dan
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> 

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