Ground polycarbonate?

As I contemplated replacing the groundglass in my recently-
acquired Seneca Improved View (full-plate size), I suddenly
wondered if anyone has ever attempted to use polycarbonate
sheet. This would solve the breakage problem, the stuff is
clear, and I'll be it's soft enough to scuff up pretty nicely with
valve grinding compound. Is it flat enough to be useful?

Idle speculation from an obviously idle mind.

TIA.

Steve

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Stephan Goldstein wrote:
As I contemplated replacing the groundglass in my recently-
acquired Seneca Improved View (full-plate size), I suddenly
wondered if anyone has ever attempted to use polycarbonate
sheet. This would solve the breakage problem, the stuff is
clear, and I'll be it's soft enough to scuff up pretty nicely with
valve grinding compound. Is it flat enough to be useful?

Idle speculation from an obviously idle mind.

TIA.

Steve

Please reply to group. If you prefer email you'll need to swap
the first letter o and numeral zero in the address.

Stephen.

Bruce Wehman uses an acrylic sheet that has window frosting film on one
side for the Wehman 8x10 cameras. I haven't heard of anyone "grinding"
plastic sheet.

Seve

On 2/6/2005 1:36 PM Stephan Goldstein spake thus:

As I contemplated replacing the groundglass in my recently-
acquired Seneca Improved View (full-plate size), I suddenly
wondered if anyone has ever attempted to use polycarbonate
sheet. This would solve the breakage problem, the stuff is
clear, and I'll be it's soft enough to scuff up pretty nicely with
valve grinding compound. Is it flat enough to be useful?

Idle speculation from an obviously idle mind.

Should work, based on my experience with both scuffing up and polishing
various types of plastic surfaces. You could "grind" the polycarb the same way
you'd do glass, against another piece of glass with abrasive compound. It'd
take a whole lot less pressure, though, since the polycarb is quite a bit
softer than glass. (As with glass, though, I'd recommend something finer than
valve-grinding compound, which is pretty coarse stuff: get yourself some
fine-grit silicon carbide powder, made for sharpening woodworking tools and such.)

Hopefully somewhat less idle speculation from a blown mind.


--
Today's bull**** job description:

• Collaborate to produce operational procedures for the systems management
of the production Information Technology infrastructure.

- from an actual job listing on Craigslist (http://www.craigslist.org)

(Stephan Goldstein) wrote in
:

As I contemplated replacing the groundglass in my recently-
acquired Seneca Improved View (full-plate size), I suddenly
wondered if anyone has ever attempted to use polycarbonate
sheet. This would solve the breakage problem, the stuff is
clear, and I'll be it's soft enough to scuff up pretty nicely with
valve grinding compound. Is it flat enough to be useful?

Idle speculation from an obviously idle mind.

TIA.

Steve

Please reply to group. If you prefer email you'll need to swap
the first letter o and numeral zero in the address.


Off hand, this would seem like a great idea - after all, polycarbonate is
essentially unbreakable, and GG breakage is what causes all LF
photographers to lose sleep.

But if its such a great idea, why haven't the manufacturer's started
doing it? Makes me suspect that there is something we are missing.

"Stephan Goldstein" wrote in message
...
As I contemplated replacing the groundglass in my recently-
acquired Seneca Improved View (full-plate size), I suddenly
wondered if anyone has ever attempted to use polycarbonate
sheet. This would solve the breakage problem, the stuff is
clear, and I'll be it's soft enough to scuff up pretty nicely with
valve grinding compound. Is it flat enough to be useful?

Idle speculation from an obviously idle mind.

http://www.satinsnow.com/html/products.html (not sure what size
"full-plate" is, but these guys are inexpensive--I have a 4x5 screen on the
way).

--
Regards,
Matt Clara
www.mattclara.com

On Mon, 07 Feb 2005 21:08:19 GMT, Louie Powell
had a flock of green cheek conures squawk out:

(Stephan Goldstein) wrote in
:

As I contemplated replacing the groundglass in my recently-
acquired Seneca Improved View (full-plate size), I suddenly
wondered if anyone has ever attempted to use polycarbonate
sheet. This would solve the breakage problem, the stuff is
clear, and I'll be it's soft enough to scuff up pretty nicely with
valve grinding compound. Is it flat enough to be useful?

Idle speculation from an obviously idle mind.

TIA.

Steve

Please reply to group. If you prefer email you'll need to swap
the first letter o and numeral zero in the address.


Off hand, this would seem like a great idea - after all, polycarbonate is
essentially unbreakable, and GG breakage is what causes all LF
photographers to lose sleep.

But if its such a great idea, why haven't the manufacturer's started
doing it? Makes me suspect that there is something we are missing.

It's easier to scratch and you can't use just anything to clean it.

Stephen


--

"Stephen" wrote in message
...
On Mon, 07 Feb 2005 21:08:19 GMT, Louie Powell
[SNIP]
Off hand, this would seem like a great idea - after all,
polycarbonate is essentially unbreakable, and GG breakage is
what causes all LF photographers to lose sleep.

But if its such a great idea, why haven't the manufacturer's started
doing it? Makes me suspect that there is something we are
missing.

It's easier to scratch and you can't use just anything to clean it.


A lot of Fresnel lenses are made of plastic, probably polycarb., so someone
thinks we can clean it without scratching it - which just takes us right
back to the 'why not use it for the focusing screen too' question.

Some screens in 35mm cameras are plastic - but of course they are much
better protected from scratching. I wonder if there is a flatness/warping
thing? Given the sizes that would be easier to address in the miniature
format.


Peter