Cloth For Bellows and a few other discoveries I made

[Ethan]

Hey everyone!

I just finished making a set of new bellows for my 8x10 camera, and while researching beforehand, I came across many people who listed one of the most challenging aspects to be finding suitable cloth for the bellows that was both thin, and light tight. Somewhere on the internet, someone recommended using the BK5 fabric from Thorlabs. This is what I ended up using for my project, and thought I would share the results here as a resource for anyone in the same situation I was. Long story short, the fabric worked amazingly. It cuts easily with scissors or an exacto knife, and laminating two layers of it with card stock ribs in the middle makes for a thin bellows that blocks all light. One layer does let some light through, but the fabric is thin enough that needing two layers is not an issue. I am not affiliated with the company which produces this cloth at all, I just thought it worked very well, and since people seem to have trouble finding good fabric, I thought I would try to help.

Another tip I have for anyone making bellows is about cutting the ribs. The ribs need to be spaced out a fraction of an inch to fold properly, this is a corner I tried to cut when making my prototype, but quickly realized it wouldn't work. The fact that ribs need to be spaced is common information, but some of the resources I found said you needed to buy a special two bladed knife to cut the strips between ribs out, or make one yourself. Making a knife from scratch like some people recommended is doable, but requires more tools than the average guy probably has. I could have done this, but found the easier route to be buying a metal one of those box cutters with break off blades, and inserting two blades into it with four layers of card stock in between to act as a spacer. If any of you end up going this route, make sure to get a relatively cheap box cutter, because you may need to bend the opening a bit to squeeze both blades and paper through, and nicer ones probably won't let you do that.

Most people also recommended laying out all your ribs together on one large sheet of paper. Getting a large sheet of card stock is expensive though, so instead I laid out patterns for all the ribs in Autocad, and printed them out on 8.5 x 11 card stock, which is much more readily available. I've attached a .pdf of these patterns to this if anyone wants to use them. The pdf is for 8.5 x 14 paper, but 8.5 x 11 also works if you cut the sides off. However with 8.5x11, on most printers the corners of the widest ribs will be cut off by the margins. This isn't a big deal if you are fine with drawing them in, but it is a bit more work. These bellows patterns are for a bellows that is 36" fully extended, roughly 11" square on one end, and roughly 6.25" square on the other. If you need bellows that are a different size, any simple CAD program can be used to lay them out. I found Autocad to be easiest, but that is probably because I know it best. A simpler program like Fusion 360 would probably work almost as well.

Hope my discoveries may be of use to someone, I may post pictures of the completed bellows soon, but I left the camera at the photo school I am interning at, so I don't have access to it at this exact moment.

Thanks,
Ethan

Bellows Templates Correct Order.pdf

[Peter De Smidt]

Good stuff, Ethan. Thanks for sharing.

[klw]

Thanks a lot for sharing. May I ask what type adhesive you used?

[Vaidotas]

Thanks for sharing.
They have european warehouse!
And blackened alluminium foil which I was looking for too.
If anyone looking for bellow making instructions take a look at Rene Smets (Lummen, Belgium) public posts on FB which includes a lot of interesting old cameras restoring projects.

[Ron (Netherlands)]

Thanks for the info!
The BK5 was extensively discussed in this thread: https://www.largeformatphotography.i...t-fabric-found.
It seems that no fellow-members in that tread ended up making a suitable bellows; some found the nylon too shiny and too thin.
Further it didn't seem easy to find a suitable glue; what is your experience?
How many of the fabric did you need/buy for your bellows?

[Ethan]

You're welcome!
The nylon is coated in polyurethane on one side, and it is quite possible that that side is too shiny, however the uncoated side is pretty matte, and so far I haven't had any issues. If other members only used one layer of the fabric, it would have been too thin. Thorlabs suggests using two layers for extremely sensitive applications, so that is what I did, and two layers is sufficient to block all light. For glue I used Loctite multipurpose spray adhesive, as well as some contact cement where I couldn't spray. I think I bought the glue at walmart, but I'm guessing you can find it elsewhere (not available directly from amazon interestingly enough). The fabric is sold in 5' x 9' sheets, one of which is more than enough for any standard size bellows. Here's a photo of the two sides of the fabric, as you can see, the poly side (on the left) is somewhat reflective, but the nylon side is matte.

Sorry for the bad photo... for better or for worse, my phone is the best digital camera I have

[klw]

Thanks

[Ethan]

For anyone interested, here are some photos of the completed bellows. The camera is a rajah 8x10 (yea, I know its a Deardorff knock off, and thus undesirable, but as a student without any income from my photography, I couldn't justify spending thousands on a camera, so this is what I have for now). The bellows easily extends to full length, and only has to be squeezed a bit to fold up the camera, though I think part of that is caused by this being my first attempt and not having perfect dimensions. The bellows are not as rigid as others I have used, and there can be a good deal of sag when extended between 14-20ish inches, so ring tabs along the top may be needed if you want to use this pattern for longer lenses.

[Peter De Smidt]

They look very good. Nice work!

[Jim C.]

Thanks for the info!
The BK5 was extensively discussed in this thread: https://www.largeformatphotography.i...t-fabric-found.
It seems that no fellow-members in that tread ended up making a suitable bellows; some found the nylon too shiny and too thin.
Further it didn't seem easy to find a suitable glue; what is your experience?
How many of the fabric did you need/buy for your bellows?

Actually the best glue to use with the BK-5 fabric is HH-66 vinyl cement from RH Products Co. Inc.
McMaster sells it in quarts. Work always intrude on my leisure stuff.