Some thoughts on bellows making

[Barry Kirsten]

Below is a pic of a 5x7 bellows I recently completed. I followed a pdf by JB Harlin which is very informative, however I ran into trouble. He suggests the top and bottom panels take their dimensions from the outside sizes of the two frames, and the two sides are sized from the inside dimensions of the frames. It didn't seem right to me because both frames are square and it seemed to me that the bellows would not be. I went ahead anyway because the mysteries of bellows design are beyond me and obviously the product of higher intellects than mine. I vaguely hoped that some mystery of the folding process and the different shape of ribs recommended might result in a square bellows for square frames, but the bellows came out rectangular, as I'd anticipated. Back to square one.

I was also disappointed with the flexibility - no fault of the instructions, but of the materials used. For the main light-tight material I used black Linno curtain blockout from our Spotlight stores, which specialise in fabrics. Excellent material for stopping light, as it consists of polyester fabric coated with three spray layers of acrylic. But sadly too thick. For the inner lining I used cotton lawn, also from Spotlight. The result was that the bellows will not stretch beyond 300mm, and I calculated on at least 360. And so stiff that I'd hate to use simple movements like moderate rise or shift with short-ish lenses. I'd say that for 8x10 or smaller cameras this sort of curtain blockout is too stiff, but it should be OK for ULF cameras which need stiffer bellows.



Where to from here... I've thoroughly searched the offerings from Spotlight, and also online sources. I can't find anything online that isn't available at Spotlight. Trouble is that none of the other materials they carry are opaque, even when tested with a sample of cotton lawn behind it. I'm happy with lawn as an inner lining, and have decided to next try an outer layer of ripstop nylon and spray the outside with flexible plastic paint applied after folding. Such a paint is available from auto spares stores and is specifically designed for plastic car bumpers to withstand bumps. I have a feeling that this will work. The ripstop nylon is very strong and light, and the flexible plastic spray might just work, as long as it's applied lightly enough to provide full opacity without increasing rigidity. Worth a try, I think.

[Peter De Smidt]

I expect that the rubber coating will make the bellows to thick, heavy and rigid. I wish that I knew a better option. In the old days, Porter's Camera Store sold black out cloth that was excellent for bellows. Organ technicians use bellows cloth for repairs, but all of this I've seen is also too thick. Places like Edmund Optics and Thorlabs sell some expensive cloth. See: https://www.thorlabs.com/NewGroupPag...ctGroup_ID=190 . But I haven't seen any in person. Maybe email the people at Intrepid camera as see what they use?

[Colin Graham]

I tried the ThorLabs BK-5 cloth a few years ago. It needs to be doubled up to be opaque, which isn't a big deal except it's also a little too shiny to be used as a liner, so by the time 3 layers of cloth are glued together it's bulky and feels starched from all the glue. These characteristics worked well for a bag bellows I made from it, but it would probably be too rigid for a pleated bellows by the time cardstock was added to the mix. It's also a little finicky about which glue it will accept. Maybe the newer cloth is different. It is expensive to experiment with.

[Luis-F-S]

Sort of why Custom Bellows makes the big bucks.................

[Graham Patterson]

Sounds just like my first-ever bellows for my home built 8x10. It would not be out of place in a heavy industrial plant. I used two (!) layers of rubberized blackout curtain because I had it to use for the experiment. On the up side, I actually learned about the process and have a functional (just) result.

I am gathering a list of possible materials Roc-Lon, LiteOn, and Duvetyne Commando Cloth blackout materials, and another suggestion I came across the other day, microsuede polyester fabric. Tandy Leather sometimes has thin leather, but it is usually close to 1mm thick. Talas has some bonded leather book cloth which is listed at 0.35mm (.875 oz) that could be promising, though shipping NY to CA is going to be a lot - it is a 56" width so it is an odd size.

If I had a standard camera I would probably try Camera Bellows, but since my home built one is liable to change if I modify the design, being able to make my own is a nice option.

Just for fun - my rectangular parallel sided bellows: http://grahamp.dotinthelandscape.org...terfolding.jpg

[Colin Graham]

Talas has some bonded leather book cloth which is listed at 0.35mm (.875 oz) that could be promising, though shipping NY to CA is going to be a lot - it is a 56" width so it is an odd size.

Last year I made a bellows out of the bonded leather from Talas. Seemed really promising when I got it, but it was pretty inflexible even with a linen liner and very thin cardstock. The paper backing of the bonded leather gets pretty rigid once the spray adhesive dries.

[Jim C.]

Finding thin materials for bellows is daunting task, there is probably a mill that makes such a such light tight cloth
for outer coverings but it's such a niche product you'll need a secret handshake to find them and an order is probably
custom run. The OP being in Australia makes doubly hard to locate and expensive to buy.

I did post some sources and observations a while back here in these threads -
Wetplate-darkbox-shroud-camera-bellows-liner-replacement-fabric-found

Talas book cloth

I'm not sure if Player Piano Corp is still in business any more, it's been a while since I last ordered from them
and their website no longer exists.

There is a seller on eBay in Japan that is selling Speed Graphic FP Shutter cloth that is .20mm thick, they may be willing to
sell much larger pieces. Search eBay for - nobbysparrow

[Graham Patterson]

Good to know. Hollander's in Ann Arbor have some imitation leather that might do - I am getting a sample book. They also list 0.65mm leather, but it is not cheap!

Flexible glue with good adhesion is a whole different problem.

[Colin Graham]

Hope it works out, would be great to have a source for material. I really liked the Porter's blackout cloth. Just before they closed I asked them who the manufacturer was but they refused to pass the name along.

I forgot to mention one other dead end I tried- the 'Original Deardorff bellows material' that was available on Ebay from that guy that bought up all the left over stock. Not even close. Thick, difficult to crease, nowhere near lightproof.

[David Karp]

I can't believe I remembered this, but Jim Galli made a bellows out of an old barbecue cover: http://www.largeformatphotography.in...hlight=bellows

So, there's that.