DIY light-tight material for bellows

[Mat5121]

Just a quick note:

You can make perfectly acceptable bellows from readily available fabrics. Get the thinnest faux leather from a large fabric retailer. Yupo is an excellent material for ribbing. Laminate with a matte black silk. Granted, this might prove too bulky for smaller formats but will be fine for 4x5 and up.

[Barry Kirsten]

I mostly followed the JB Harlin instructions for making the tapered ribs--for whatever reason, these look like they'll fold about perfectly square.

In my experience they won't. Harlin takes his measurements from the inside and outside of the frames to get the sizes of the top/bottom and two side panels. I think that's why one end comes our square and the other rectangular. Which end comes out which way depends on how you start the fold sequence. I cannot see how you can get two square ends when different measurements are used for the two sets of sides. Harlin suggests a paper mock-up to see how it will go. Being impatient I didn't go that route, and ended up with a bellows I don't want to use.

[devb]

What about the material from a film changing bag?

[Randy]

Just throwing this out - the bellows on my Folmer & Shwing 8X10 (Commercial View I believe) is some sort of "rubberized" material bonded to cloth...as best as I can tell - almost like a very thin wet-suit material. And I am guessing, based on the appearance of the outside, that it is very likely the original bellows. My camera was made in the 1920's. I have had it for about 20 years. There are no signs of degradation or failure in the material, inside or out. No cracks in the corners or splitting along the ribs, no "dry rot", nothing. I have not treated the material with anything...mainly because I would have no idea what to put on it since it is not leather.
I guess none of us need a bellows that will last 100+ years, but who ever made mine sure knew what they were doing.

[michael_wi]

I have been experimenting with a couple of materials. The base is a black top sheet (not fitted corners, more material).

I have brushed black thinned acrylic paint in several layers. There is some leak through to the reverse side. Can barely see a portable strobe fired through it. Some minor pinholes.

I have airbrushed thinned acrylic in several layers. Flater finish with no leak though. Same result as above.

The last material is a plastic tool handle type dip. It is also used as liquid electrical tape. It was thinned about 50/50 with naptha and spread with a plastic card. Some pinholes, very flexible, matte finish after a couple of layers.

Any of these if done on both sides would make the bellows light tight and very thin.

Michael

[Michael Cienfuegos]

I have been experimenting with a couple of materials. The base is a black top sheet (not fitted corners, more material).

I have brushed black thinned acrylic paint in several layers. There is some leak through to the reverse side. Can barely see a portable strobe fired through it. Some minor pinholes.

I have airbrushed thinned acrylic in several layers. Flater finish with no leak though. Same result as above.

The last material is a plastic tool handle type dip. It is also used as liquid electrical tape. It was thinned about 50/50 with naptha and spread with a plastic card. Some pinholes, very flexible, matte finish after a couple of layers.

Any of these if done on both sides would make the bellows light tight and very thin.

Michael

My question is: won't the folds stick to each other when compressed? Even after that stuff cures, it is a bit sticky.

m

[michael_wi]

Futher testing of the plastic coat/liquid tape and the acrylic paint.

Neither will stick to itself with compression or heat. For the heat I used an iron set to Wool. I was hoping the acrylic would melt to itself to remove wrinkles and act as a binder.

Kust waiting for the spray adhesive to set up fully before trying to take it apart. Minor pin holes in both coatings are no longer visible.


Some other materials from around the web are:
- material used for awnings or blackout curtain and a dull black and close woven fabric, basically a liner for women clothing
- leather, leatherette or canvas on the outside, as thin as possible, but light tight and a thin black cloth with a paper backing ,ie bookbinder's cloth
- A good bellows can be made of imitation leather with a black cambric lining. A better bellows uses thin black kidskin with black rubberized cloth lining. For the best, use thin black opaque vinyl and a black rubberized cloth lining.
and the of course the changing bag, photo paper plastic bags, Gortex, rubberized nylon

Other than bookbinder and Gortex, I get funny looks from the ladies at the fabric stores. OF course that could also be from the light meter I am holding.

[noci]

For wide angle bellows where sagging is not an issue, I've used neoprene before, something akin to the way the Cambo Actus bellows look (hex pattern, glued and folded inside out, then individual elements attached). Neoprene is horrible to work with, but used with the right e.g. urethane glue, once you have it done, it's virtually bomb-proof. Lugged those bellows all over Japan with me this summer and no issues whatsoever.
m

[Mike1052]

Thanks for the comments so far. I drew up rib patterns for straight and tapered bellows today, and laser cut the parts from 180 lb gray card stock--apx. 0.015 thickness. Also found some flat black 'poster board' at Michael's craft store for $0.99 per 20"x28" piece which is a bit thinner--apx. 0.010"--I'll try that next. Pics of the ribs below. Note the little tabs between ribs to hold them together. In the Intrepid Camera video of bellows assembly, this appears to be how they do it, and it looks like it will work well.

I mostly followed the JB Harlin instructions for making the tapered ribs--for whatever reason, these look like they'll fold about perfectly square.

Laser cutting saves a lot of labor, and most of the other materials are either inexpensive or stuff I had on hand. So I'm not too worried if the first iteration or two fails.

More pics as the assembly continues, hopefully later this week...

Attachment 167720Attachment 167721Attachment 167722Attachment 167723

Hi

Do you have a link to the Video you mentioned???

[Pfsor]

...
I gave both materials a coat of flat black paint (Krylon Dual Superbond, claimed to stick to plastics), which seems to block all light. After an hour dry time, the paint appears well-bonded to substrates.

Make no mistake - painting your material can easily make it light tight. But the paint has nowhere the strength of the bellows material needed for not developing pinholes when bent over and over and again as bellows do. Otherwise people would just paint plain paper, wouldn't they. The paint can never replace the bellows material's function. Period.
Let others make your bellows professionally. It's also called Custom Bellows. In UK, that's it.Your home-made camera will only be better because of that.