Flat Black - where, what ??

Has anyone found a flat black that will not burnish when touched
and handled?

In the midwest.

TIA

Burnishing means: flat black rubs to a reflective glossy surface
when touched which is the very opposite of what and why flat black is
for.

We need a flat black that will not burnish when touched and handled. A
flat black that stays FLAT!

Thanks-

Peter Weld wrote:

Has anyone found a flat black that will not burnish when touched
and handled?

In the midwest.

TIA

FLAT BLACK sold at wal-mart for just about $1.00 I have used it on my
Stargazer Seve Dob for over 6 years.


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"Peter Weld" wrote in message
...
Has anyone found a flat black that will not burnish when touched
and handled?

In the midwest.

TIA

Peter Weld wrote:
Has anyone found a flat black that _will not burnish when touched_
_and handled?___

In the midwest.

TIA




If it's that much of an issue, have you considered roughing the surface
before painting it? I've seen folks who have used all sorts of things,
like sawdust and shredded pvc, glued to the inside of the tube and then
hit with krylon flat black. Works really well.

'luck - Chris

On Tue, 24 Apr 2007 14:44:51 -0500, Peter Weld wrote:

Has anyone found a flat black that will not burnish when touched
and handled?

What you want may not exist. Flat black paint works in part by leaving a
surface of randomly oriented particles or fibers. They are naturally
fragile, and can easily be polished off by contact, or filled with skin
oils.

Normally, if you want a surface to have low reflectivity you need to
modify it mechanically- some sort of bead blasting, cutting fine
grooves, etc. Then you apply the flat black paint. A prepared surface
like that is much more resistant to contact.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

In many if not most places (in a telescope) glossy black can be
substituted for flat black with superior overall results when viewed
at the eyepiece or focuser.
--
Bill

starburst wrote:

Peter Weld wrote:
Has anyone found a flat black that _will not burnish when touched_
_and handled?___

In the midwest.

TIA




If it's that much of an issue, have you considered roughing the surface
before painting it?

Cant do that. Parts are machined and have to remain smooth
to fit, but must be flat black that will not burnish when touched.
These are interchangable lens housing, grating mounts, etc etc
all in confined light tight boxes.
Thanks -
Pete

I've seen folks who have used all sorts of things,
like sawdust and shredded pvc, glued to the inside of the tube and then
hit with krylon flat black. Works really well.

'luck - Chris

understand the principle however there used to be flat blacks
like that sold by Edmund that did not burnish - the same for
most parts from Perkin Elmer, Melles Griot, etc ... Takahashi ...
whatever it is they are using. Take a good eyepieve and rub the
inside of the barrel - doesnt burnish. Maybe I should ask TeleVue
or somebody like that ....
Thanks -



Chris L Peterson wrote:

On Tue, 24 Apr 2007 14:44:51 -0500, Peter Weld wrote:

Has anyone found a flat black that will not burnish when touched
and handled?

What you want may not exist. Flat black paint works in part by leaving a
surface of randomly oriented particles or fibers. They are naturally
fragile, and can easily be polished off by contact, or filled with skin
oils.

Normally, if you want a surface to have low reflectivity you need to
modify it mechanically- some sort of bead blasting, cutting fine
grooves, etc. Then you apply the flat black paint. A prepared surface
like that is much more resistant to contact.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

"W. H. Greer" wrote:

In many if not most places (in a telescope) glossy black can be
substituted for flat black with superior overall results

now that is a novel principle - care to explain?
Pete



when viewed
at the eyepiece or focuser.
--
Bill

Bill Greer wrote:
In many if not most places (in a telescope) glossy black can be
substituted for flat black with superior overall results

Pete wrote:
now that is a novel principle - care to explain?

I'm not Bill, but I'm guessing it's because glossy black reflects little
light (because it's black), and what it does reflect, goes in a very
particular direction, which most of the time is not toward the eyepiece.
Whereas with flat black, which reflects diffusely, light hitting any
place in the tube has some chance of making it into the eyepiece.

It's like if you look at a streetlight in a mirror. Most of the mirror
is not reflecting any light into your eye; it's only the small part of
the mirror where you see the streetlight's image that is directing any
of that light toward you. Whereas if a cement sidewalk is the thing
that's reflecting the light, any individual part of the sidewalk is
less bright than the one part of the mirror, but all parts of the
sidewalk reflect *some* light toward you.

--
Brian Tung
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