I made sure I was light tight by applying adhesive-backed matte black vinyl to the inner layer. It's super thin and creases nicely. It might tear or stretch over time on the corners, but it's worked well so far, and can easily be patched with more of the same. It's so thin that the addition patch layer would be negligible.
I've used the blackout fabric for one bellows, for an 8x10---where the the front standard is the same size as the rear, with a 4foot bellows extension (macro photos with an 18" lens...) the seam causes a thickness issue that runs almost 2" difference to the un-seamed sides when it's all compressed for transport. If I were doing it again, I'd stagger where the seam overlaps to make the tube but for my purposes it is o.k. I will probably revisit that material for the 8x10 field camera I'm restoring, staggering the seam and making the folds as big as I practically can given the design of the old camera. I have but fragments of the original bellows to go by. White exterior is nice in that it stays cool but shows dirt like crazy.
I've also thought about making bellows for other even crazier ideas and thought that some variation on a bag bellows might work for some of what I have in mind i.e. a 14x17 studio camera and use external loops glued on and use the loops to support the bellows out of the optical path. It won't be as pretty as other solutions but it ought to work. If the bellows clipped in and out of the cameras easily enough or folded well enough, they might even be useable in cameras in the field. Of course if the 8x10 thing project works well enough, I might just make the bellows the "traditional" way. This is a long ways into the future before I attempt the 14x17.
Reviving this thread because I've revived my camera project. Monorail 4X5 about 80% complete, built from carbon fiber panels and 3D printed parts, with expected weight ~ 1000 grams. I'll post when finished.
Not surprisingly, bellows materials has continued to be a challenge (and yes, buying custom-made bellows is a viable alternative, as is buying a complete camera off eBay--my interest here is what can I do/learn to do myself). After bellows constructed from materials as outlined above proved to be slightly less than light-tight, I bought some BK5 and constructed another set--two layers of BK5, outer layer of 1.1 oz. nylon, flat black spray paint on the inner polyester surface of the BK5 to knock down the gloss. All layers bonded with 3M 30NF Fastbond contact cement. Bellows bonded to frames (savaged from Cambo bellows) with VOC-compliant version of Pliobond.
It works well enough. Light-tight, holds a crease, looks okay. But heavier than the original Cambo bellows by about 60 grams, and thicker as well:
So, try again. Made samples with BK5 bonded to 50# kraft paper (~0.005") and 1.1 oz siliconized/polyurethane ripstop polyester (From Ripstop By the Yard--1.4 oz/ sq. yd. after coating). One coat of matte black spray paint on the BK5 + kraft paper layer, before bonding the ripstop poly. All layers bonded with 3M Fastbond.
Verdict: Perfectly light-tight. Thickness ~ 0.013" (0.3mm). Kraft paper is plenty stiff to form ribs. BK5 adhesion: contact cement bond between BK5 and silpoly/PU will peel (with effort), leaving clean BK5 rubber surface. However, bond is strong enough that attempting to peel BK5 from sandwich with kraft paper in the middle, results in kraft paper splitting and leaving paper on each fabric. In practical terms, that seems strong enough.
In the next day or two, I'll finish a full bellows with this method and bond it to 3D printed bellows frames. Should save 50-100 grams over my previous effort, and the Cambo original.
Good work!
“You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
― Alexander Den Heijer, Nothing You Don't Already Know
Indeed nicely done. I'm into making myself some bellows for a half plate 1910 British camera, however looking from pictures the orginal bellows had straight corners.
Does anyone have a template for bellows with straight corners? - the bellows itself are tapered.
Here's a picture of the camera - it's a Pembroke
Finished Bellows #3 today. Used laser-cut drafting mylar for ribs, which seems an ideal material: light, thin, stiff. Bellows weigh ~130 grams without frames, 0.33 mm (0.013") thick, 400+ mm expanded, 20 mm compressed.
Used 1.1 oz. calendared ripstop nylon again for the outer skin. It's a very thin, soft fabric--but hard to work with and frays on the cut edge. I just received an order of the siliconized/polyurethane fabric referenced above, and I'll build Bellows #4 with it next week. Hopefully, that one's a keeper.
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