Bellows, how do they work?

[steven_clark]

So I'm planning to make a set of replacement bellows for an

Isolette and I got to thinking about how bellows are

constructed. As far as the image in my mind goes a single

segment of bellows should not be able to move if made

with rigid pieces hinged together. This means literally

something has to give. What is supposed to flex in a

bellows? so I can account for that in my construction and

avoid putting wear someplace it doesn't belong.

[savagesax]

I'm not sure if I understand your exact question, however if the bellows was smooth, no rigid's, light would reflect

and bounce inside, thus causing all sorts of unwanted light reflections on your photo's.

 

Can you tell us more about the camera? Does the camera have a built in bellows, such as some of the 4X5 cameras and even large 8X10 field cameras?

 

There are places around that make bellows replacements.

[lex_jenkins]

<p>I see online some small illustrations from older camera repair manuals that showed how to make bellows from scratch. Looks pretty labor intensive. There are several sources for ready made replacement bellows on ebay and elsewhere. I'd check those first. Even if you'd rather tackle the project yourself, having a sample of a working bellows to guide you would help.</p>

<p>While it won't be suitable for a folding camera like the Agfa, there are simple bag bellows that are easy to make. These were primarily designed for wide angle lenses on view cameras. But I've made my own bag bellows for homebrewed tilt shift macro lenses for use on SLRs. Any matte black lighttight material will do. I've also used the lighttight black plastic bags from boxes of darkroom printing paper. Not ideal, but it worked.</p>

[SCL]

<p>Your public library might have a copy of Tomosy's classic camera repair guide, in which he gives detailed instructions and patterns for replacing and constructing your own bellows.</p>

[steven_clark]

Isolettes are medium format folders. In this case a 6x6. I've removed and cut the original bellows

so I can flatten them for reverse engineering, but there are so many pleats in this bellows design

that they are small and hard to measure accurately. I was hoping someone knew some engineering

principles I could use to sanity check my work.

 

 

As for the original question: some basic geometry in my head says the lengths of some sides of the

stiffeners need to change as the bellows extend. If the stiffeners were completely rigid(like made

of steel) the design wouldn't work at all. I'm guessing that the long sides in the stiffeners have to

bow out/in for the bellows to flex and wondering if that needs accounting for. I'm assuming if the

change of shape happens at the corners it causes more wear and eventually premature pinholes.

 

I've already purchased some blackout liner and broadcloth to build it and my time isn't very valuable

right now while I'm short on money. Also I wasn't sure that the bellows on eBay would work in my

particular camera without fault or modification.

[lex_jenkins]

<p>Depending on condition you may be able to repair the existing bellows. When I rebuilt my Isolette folder about 12 years ago I used black fabric paint to repair the pinholes in the bellows. Often used to decorate t-shirts, fabric paint is flexible and durable and has lasted for many years. If the pinholes are a bit too large to touch up with paint, try cutting small strips of black matte fabric to patch the holes.</p>

[savagesax]

I really like Lex's ideas. I had an old bellows extension for duplicating 2 1/4 positives, (color slides). I used black

finger nail polish, but Lex's idea of flexible t-shirt paint and black cloth sounds like a winner. At that time I was using

Hasselblads.

 

Would this work for what you want to achieve?

[Matthew Currie]

<p>Another possibility for small spot repairs is a plastic stuff called 'liquid electrical tape.' I used some long long ago on a small repair, and it seemed to work pretty well. It's a black goo that dries flexible.</p>

[jose_angel]

<p>There are some DIY bellows sites on the web.<br /> But I agree with the "fix it yourself" idea. I`ve used from white cotton surgical tape (which I panted on black, for very tiny holes) to darkroom blackout materials. There are very thin courtain materials that can be glued with neoprene contact glue ("Black Witch"). It works.<br /> Ordering and replacing with a new bellows is easy, the main problem is to dissemble the camera to have workable parts. On large format cameras it`s so easy, on my Mamiya 6 seem something quite complex, so here I opted for the "tape and fix" approach.</p>

[steven_clark]

<p>Oh, the camera is already disassembled at this point, should be easy to reassemble. My efforts before to fix the pinholes with sealant were only worked on half the corners. Since these bellows are enameled paper on the outside there's a hole in every corner and the corners are small so tape would have been a pain. I couldn't find bellows for Isolettes with an Ebay search. At this point I've already taken scissors to one of the side of the original bellows so I could flatten them for examination. It appears most of the flexing is done near, but not at the corners and the stiffeners either don't extend all the way to the corners or are slit at a right angle near the corners. I'm going to copy that idea for mine so all my stiffeners will be rectangles.</p>

[steve m smith]

<p>Here is my method for making bellows for 5x4 cameras. It might answer some questions.</p>

<p><a href="http://stevesmithphoto.webs.com/bellows.html">http://stevesmithphoto.webs.com/bellows.html</a></p>