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-   -   how to apply cerium oxide to polish polyurethane plastic (http://www.craftbanter.com/showthread.php?t=11507)

Jack September 14th 03 02:56 PM

how to apply cerium oxide to polish polyurethane plastic
 
Hi,

I am considering using this to polish some cubes I have cast to get a
translucent and shiny surface, but I wanted to know how this was done,
as the product is in powder form...do I add water or is there some
special application approach to using cerium oxide ?

thank you

jack posemsky

Steve Richardson September 14th 03 04:08 PM

Cerium oxide is used quite a bit by amateur telescope makers, to put a final
polish on mirrors. It's a quicker-acting substitute for jeweler's rouge
(and boy, am I ever showing my age by remembering when that was the
standard!) With either, you use water. Depending on the size of your cubes
you might want to use a buffer pad on a Dremel but be very, very, very
careful because the pad alone with nothing on it at all can melt plastic due
to sheer friction. Another way would be to use a piece of window glass
(larger than the cube's face) as a tool. Sprinkle the cerium oxide on it,
spray some water over the powder, set the cube on top and go to work.
You're probably going to find that the polish comes up in some places and
not others because it's highly unlikely that the cube faces will have cast
out as flat as the window glass you're using for a polishing tool. If
that's the case you can either go to the bother of switching to an abrasive
and grinding each face down flat on this same tool, using progressively
finer grits until you're ready to try polishing again, or if the cubes are
small enough you can work with the cerium oxide on a wet soft lint-free
cloth and try the polishing by hand. It'll take a long while but it can be
done. One other thing to watch for -- whether you're using a tool or a hand
cloth, there's going to be a tendency for the cube's edges to blunt a
little, ditto for the corners. Oh, and watch out for sticking if you
decide to use a glass tool. If the cerium oxide dries out during the
polishing it can be hard to separate the two bits, so keep it wet while
polishing.
- Steve Richardson (former amateur telescope maker - well, just the one....)

"Jack" wrote in message
om...
Hi,

I am considering using this to polish some cubes I have cast to get a
translucent and shiny surface, but I wanted to know how this was done,
as the product is in powder form...do I add water or is there some
special application approach to using cerium oxide ?

thank you

jack posemsky




Michele Blank September 14th 03 09:04 PM

we use the cerium oxide in slurry form, with a lapidary polishing tool that
also keeps it wet. This is only the last of multiple polishing stages .Take
a look at kingsly north or similar for lap tools. m


"Steve Richardson" wrote in message
y.com...
Cerium oxide is used quite a bit by amateur telescope makers, to put a

final
polish on mirrors. It's a quicker-acting substitute for jeweler's rouge
(and boy, am I ever showing my age by remembering when that was the
standard!) With either, you use water. Depending on the size of your

cubes
you might want to use a buffer pad on a Dremel but be very, very, very
careful because the pad alone with nothing on it at all can melt plastic

due
to sheer friction. Another way would be to use a piece of window glass
(larger than the cube's face) as a tool. Sprinkle the cerium oxide on it,
spray some water over the powder, set the cube on top and go to work.
You're probably going to find that the polish comes up in some places and
not others because it's highly unlikely that the cube faces will have cast
out as flat as the window glass you're using for a polishing tool. If
that's the case you can either go to the bother of switching to an

abrasive
and grinding each face down flat on this same tool, using progressively
finer grits until you're ready to try polishing again, or if the cubes are
small enough you can work with the cerium oxide on a wet soft lint-free
cloth and try the polishing by hand. It'll take a long while but it can

be
done. One other thing to watch for -- whether you're using a tool or a

hand
cloth, there's going to be a tendency for the cube's edges to blunt a
little, ditto for the corners. Oh, and watch out for sticking if you
decide to use a glass tool. If the cerium oxide dries out during the
polishing it can be hard to separate the two bits, so keep it wet while
polishing.
- Steve Richardson (former amateur telescope maker - well, just the

one....)

"Jack" wrote in message
om...
Hi,

I am considering using this to polish some cubes I have cast to get a
translucent and shiny surface, but I wanted to know how this was done,
as the product is in powder form...do I add water or is there some
special application approach to using cerium oxide ?

thank you

jack posemsky







Mike Aurelius September 15th 03 02:14 PM

Cerium oxide WILL NOT WORK to polish plastic.

If you have a optical laboratory near you (one that grinds and polishes
plastic lenses for eyeglasses) ask to buy a pound or so of plastic lens
polish. It is basically tin oxide and aluminum oxide mixed together. It is
super fine material, finer than cerium oxide.

Cerium oxide is glass polish. Tin/Aluminum oxide is plastic polish. Very big
difference in surface finish.

Mike



Michele Blank September 15th 03 05:07 PM

oops! i missed the end of the subject line where plastic was specified. i
was of course referring to polishing glass! m

"Mike Aurelius" wrote in message
...
Cerium oxide WILL NOT WORK to polish plastic.

If you have a optical laboratory near you (one that grinds and polishes
plastic lenses for eyeglasses) ask to buy a pound or so of plastic lens
polish. It is basically tin oxide and aluminum oxide mixed together. It is
super fine material, finer than cerium oxide.

Cerium oxide is glass polish. Tin/Aluminum oxide is plastic polish. Very

big
difference in surface finish.

Mike





nJb September 15th 03 08:10 PM

Mike Aurelius wrote:

Cerium oxide WILL NOT WORK to polish plastic.

If you have a optical laboratory near you (one that grinds and polishes
plastic lenses for eyeglasses) ask to buy a pound or so of plastic lens
polish. It is basically tin oxide and aluminum oxide mixed together. It is
super fine material, finer than cerium oxide.

Cerium oxide is glass polish. Tin/Aluminum oxide is plastic polish. Very big
difference in surface finish.

Mike


What next? My glass firing schedules won't work for plastic?
--
Jack


http://photos.yahoo.com/bc/xmissionbobo/


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