Topic: Bellows advice

[jharr]

I downloaded some templates for replacement bellows for my Isolette III. When I laid out the stiffeners on the inner lining, the wide and narrow ribs do't line up. It seems like they should. I think I can offset them like in the photo, but I don't want to glue them down until I am sure. Can someone give me some thoughts on this?

[Francois]

I don't know how they made their template but it's quite possible it was designed like this.
Bellows follow the pattern of out-in-out-in so I think it's quite normal that you have two sets of cardboard stiffeners.

But I'd rather wait for someone who has experience with such things to chime in before you commit to gluing the thing.

[jharr]

Actually, I think I can answer my own question. Once I flattened out the old bellows and looked closely, it made more sense. The folds go alternately so the 'peak' on the top and bottom aligns with the 'valley' on the sides. So the template is right.

[Ezzie]

As you have found out, they need to be like that. You may have noticed that there are narrow and wide stiffeners as well. Also a necessity for tapered bellows. From front to back the narrower fold down and wider back up.

[Sandeha Lynch]

That's pretty much the way of it, though I'd suggest you use a thin black card or a thick black paper.  The three layers need to be pretty thin so that the bellows lie flat enough when compressed.

[Francois]

Actually, I think I can answer my own question. Once I flattened out the old bellows and looked closely, it made more sense. The folds go alternately so the 'peak' on the top and bottom aligns with the 'valley' on the sides. So the template is right.

This is actually needed in order for it to fold. Otherwise, the bellows would become rigid and crack when compressed.
I think I have done too much origami when I was a kid...

[Terry]

James,
I've also found it helpful to make a cardboard "cone" and lay out the pattern on it.  I also use it to assemble the fabric and stiffeners.  Personally, I find it difficult to "see" the bellows on the flat, and having a 3D template makes sense of the structure for me.

[jharr]

James,
I've also found it helpful to make a cardboard "cone" and lay out the pattern on it.  I also use it to assemble the fabric and stiffeners.  Personally, I find it difficult to "see" the bellows on the flat, and having a 3D template makes sense of the structure for me.

Thanks Terry. I did end up making one out of foam core and Gorilla Tape. It does help, especially with getting the seams together. Unfortunately, I sort of messed up my first attempt. I put the seams for both fabric layers on top of one another. That makes it too thick to really fold on that side, so I will have to start over. I think I need better glue as well. Maybe a spray-on type will work better.

The best part of the cone is that when I am done making bellows, I can convert it to a pinhole camera!

[Francois]

You know, you could very well take that cone, put it on a table and call it a work of art

[Alan]

...reminds me of this >