Bellows Material - might have found the answer

[joshwool]

I just used household blackout curtain fabric. It's white, but it was what was locally available for $10/meter (in Canada). It's somewhat of a thicker fabric, but I liked how it turned out for an 8x10 bellows--giving the bellows a certain weighty feel and stiffness to it. I used cardboard ribs and just black broadcloth for the inner lining.

I made 2 bellows and made a different mistake on both of them: On the 8x10, I didn't alternate the narrow/wide ribs between the top/bottom and sides. Because the folds alternate between the top/sides, the ribs also need to alternate. This results in the bellows top/bottom folding flat, but the sides folding up/down. It still works, but doesn't fold flat.

The other bellows was a 5x7 and that I didn't measure it correctly: The top/bottom dimensions are the horizontal width of the opening of the back of the camera and lens standard. The side measurement is the length of the side minus the width of the top plus bottom ribs. The result was that the bellows was around 3/4" too large in the vertical dimension.

My next bellows should be good, but if you can avoid those 2 errors, making a bellows is totally doable, but fairly tedious. Both bellows had around 160 ribs each. In the end, it's quite a satisfying experience!

Attachment 239689
Attachment 239690

Thanks for the tips, I'll definitely keep an eye out for those issues. Still wrapping my head around the rib sizing, but I'm going to use the old bellows as a reference point.

[Dan Dozer]

I've made several bellows before ups to 8 x 20 size trying out different materials. Best I found was standard drapery black out material on the inside (spray painted black) and a thin type black Egyptian cotton that I found at the local fabric store (very inexpensive). Best resource I found on learning how to make bellows is "Restoring Classic & Collectable Camera" by Thomas Tomosy. It has a chapter on bellows making that pretty much tells you all you need. One important thing is the adhesive you use for gluing the cardboard stays to the fabric needs two work with both. i used a simple liquid type glue stick I got at the local store. It worked fine but has come loose in some places.

[joshwool]

Just received the material, not quite as 'black out' as I had hoped, but when outside I'd say it blocks approximately 90-95% of light, doubled up 100% black out. It's very thin, so doubling it would still make it the equivalent of 150 denier, which is shouldn't be an issue. It may be fine as is with the broadcloth as an internal layer, will have to do some testing

[jimskelton]

The narrow/wide rib sizing is interesting. Once you determine the total rib size (from top fold to top fold), then each side size (remembering to subtract 1x the fold size from the sides), then draw the top shape based on how long you want it (adding around 20% for the folds), you draw horizontal lines the width of the total rib size (top fold to top fold), then make a right angle triangle with the long edge spanning the total rib distance. Place the long edge of the triangle on the edge of the bellows template. The point at 90 degrees indicates the fold line between the total rib size. If you mark that, then you can measure the different rib sizes, subtracting 1-2mm per rib for the fold, likely 1mm for yours since your fabric is so thin. Once you determine rib width, a bunch of ribs can be cut, then each sized separately for each row of the bellows. Once you start, it's more tedious than difficult...

Thanks for the tips, I'll definitely keep an eye out for those issues. Still wrapping my head around the rib sizing, but I'm going to use the old bellows as a reference point.

[joshwool]

The narrow/wide rib sizing is interesting. Once you determine the total rib size (from top fold to top fold), then each side size (remembering to subtract 1x the fold size from the sides), then draw the top shape based on how long you want it (adding around 20% for the folds), you draw horizontal lines the width of the total rib size (top fold to top fold), then make a right angle triangle with the long edge spanning the total rib distance. Place the long edge of the triangle on the edge of the bellows template. The point at 90 degrees indicates the fold line between the total rib size. If you mark that, then you can measure the different rib sizes, subtracting 1-2mm per rib for the fold, likely 1mm for yours since your fabric is so thin. Once you determine rib width, a bunch of ribs can be cut, then each sized separately for each row of the bellows. Once you start, it's more tedious than difficult...

That's very helpful, thank you. Hopefully starting this project in the next week or so.