Re: How to remove yellowing from monitor?

["Mark Cummings" <figjams@primus.com.au>]

Hilary,

I like your Vaseline idea very much, it sounds like it will work well.
And I'm glad you pointed out the short falls of using bleach, I had the same
thought myself. I know if it's left in a plastic spray bottle it will
greatly reduce the life of the bottle and it's rubber parts. I wonder if the
person who suggested this had any experience or was just taking a wild guess
at someone else's expence.
I have some severe oxidisation and stains on a non-Apple monitor (a clone
actually) and was wondering what you think of the idea of using a sand
blaster to strip it back while possibly maintaining a matt non-reflective
surface, prior to hitting it with Vaseline. I don't really like the idea of
using sand paper (cross hatching or otherwise), because I doubt I could ever
do it in such a way as to make an even pattern over the whole surface.
Another approach that I was seriously considering was repainting it in
Acrylic paints, colour matched to the original. Although I havn't done this
for any plastic cases, I have already restored two metal cases to their
original colour and finish. One was a Generic CDROM external case that was
badly scratched. And the other was the metal casing for an AMR 3.5" floppy
drive which was also scratched. To get the colour match I took the original
case to the local paint shop who used a colour matching device/computer. The
inside of the case was still like new, so that's where the colour was
derived from. Their computer tells them how much of what colours to add to
how ever much paint you need. In my case they were happy to just make up a
small 250ml (1cup) can, and it cost less than $10AU ($5US) for the paint.

Mark


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In article <3B7AD7DB.5875F315@ozemail.com.au>, "Hilary M. Turner"
<hilarymichael@ozemail.com.au> wrote:


>WARNING!!!!!!!!!!!!!!!
>
>    Do not use any Bleach on plastic or any cleaner which has any type of
Bleach
>in it.
>
>
>    WHY?  It does more damage to any plastic then years of exposure to UV
light.
>
>    Bleach strips the chemicals which bind the plastic together and cause
rapid
>oxidation of the remaining plastic making them very brittle.
>
>    If you feel that the coloring is distracting then use "Wet and Dry
abrasive
>paper" in the 600 and above grit and use it wet. Yes you will remove the
>non-glare texture but if you want use 300 W/D paper after its clean by
cross
>hatching and it will revive a non-glare surface. There are more complex
method
>of doing this but require knowledge of the type of plastics you are working
on.
>
>    Then the cheapest way to revive the plastic, that is to put some of the
>chemical back into it, is to use WPG (white petroleum gelly "Vasolen"}.
This is
>done by worming the plastic in the Sun until you can feel the warmth on the
>inside of the plastic and then applying a thin coat of WPG over the
exterior of
>the plastic and rub it in and re-worm the plastic. Should be done several
times
>then left a several days so the max is absorbed into the plastic. If after
its
>let dry for a couple of days it is dry !DO IT AGAIN!!!. Leaving it for a
few
>days it should still be sticky. This means that the plastic has taken in
all it
>can at this time.
>
>    Then a couple a times a year reapply a small amount of the WPG and rub
it in
>and wipe it off. You will probably find plastic oxides on your cleaning
cloth in
>both cases. This is good as in all things that oxidize oxides cause more
rapid
>oxidation. Also the WPG fill the gaps in the plastic, which would be only
>visible under a microscope, with WPG so it will always fell a little
slippery or
>wet. This also mean that water or any other type of fluid will not stain or
>ingress into the plastic and make it easier to clean in the future.
>
>    Disassembly of the monitor is not difficult and if you are keen enough
to go
>to the extent I have outlined then removing the complete case is not
anything of
>an extra but rather just the start of the procedure.
>
>    The more expensive: Use a vinyl referbisher. Like anything that is sold
for
>cleaning your car dashboard and seats. But WPG is cheaper and just or more
>effective. Which you should be able to pick up at any hardware or car shop.
>Getting is also a lot cheaper then using "Vaseline" as a half or quarter
pound
>will cost you less then the smallest jar of "Vaseline" Which works well in
the
>car also.
>
>    If you like I can explain in detail how to get the best texture back
into
>the plastic just let me hear on this newsgroups and I'll write it up.
>
>     Hilary Retired Aircraft mech.
>
>
>
>