> Wayde Allen wrote:
>
> > I've been trying to locate a source of sufficiently thin leather.
>
> Make friends with a local book-binder. They use very thin leather to
> bind old books and to restore bibles. They also have a synthetic leather
> look-alike that is also very thin. Also, I think it was View Camera
> magazine that published a "build your own bellows" article awhile back.
> You may want to check into that as well.
I've got a copy of that article, and several others. It is a fairly good
description of what is involved, however, the author says that he
purchased a large amount of a rubberized fabric from somewhere that he
can't remember, and that he doesn't know what it is called. He does say
that he will send a sample of what he has so you can see what it looks
like. A set of instructions with a slightly different approach can be
found on-line at: http://www.cyberbeach.net/~dbardell/bellows.html.
I've talked to several bookbinders, and have hopefully ordered a catalog
of supplies (left my name and address on the answering machine anyway). So
far no real luck, but I'll keep trying. The problem is that they can use
thicker materials than we might like for bellow making. Basically, the
material needs to be as thin as possible while still remaining opaque.
Each fold adds two layers of fabric so if you've got say 36 folds the
thickness really starts to add up:
Collapsed thickness = 2 * (# of folds) * (wall thickness)
This is the theorectical limit if the folds are perfectly square and
stack. In reality it will be a little thicker than this. Of course you
can make a tapered bellows with a steep enough taper that allows
successive folds actually collapse inside of the preceding ones. That
helps. The other problem is that the material needs to remain flexible.
Most of the synthetic leathers I've found so far are a type of vinyl.
They look pretty good, but a practice bellows I made from this stuff gets
rather stiff when it gets just a little bit cold.
Rubbermaid sells a shelf paper lining material at the local hardware store
that is very thin, has a nice finish, and is fairly light tight. There is
some light transmission, but this can be dealt with by the choice of
bellows liner material. I tested a piece by adhering it to a sheet of
aluminum foil. It also seems to remain flexible even when dipped in
liquid nitrogen. The problem is they only sell rolls 18 inches wide.
Anyway, we're probably stretching the limits of what most people consider
the purpose of this list. If anyone wants to continue this conversation,
we can move off list.
Thanks for the suggestion to check out the Shutterbug adds. I'll have to
see what I can find there. Don't know why I haven't looked there already.
- Wayde
(wallen@boulder.nist.gov)