Thoughts on replacing aperture blades

[benrains]

I picked up an old barrel lens with a mucked up aperture. Most of the blades are in good condition, but it looks like 3-4 need to be replaced and one is missing altogether. I've reassembled apertures before (I learned how to do my first one the hard way when I accidentally dropped all the blades out of lens I was cleaning.) That part is not a big concern to me. What I don't know is what are common ways to fabricate missing or broken blades, and specifically, what are good substitute materials for the blades?

My current thinking is that I can contact print one of the existing good blades onto a sheet of lith film, and then use this as a negative to print replacement blades onto more lith film. These would then be carefully cut out with a sharp razor knife. The brass pins for holding the blades in the aperture ring I think I can make from a suitable gauge of brass rod... with one end filed flat and the other peened slightly to keep them from slipping through the holes in the blades.

[David McNiven]

If you're unfamiliar with the word "shim" try google or Wiki perhaps.
Various thicknesses available (from a couple of thou') in plastics, brass, stainless etc.
Laser cutting is easiest & is accurate but expensive unless you own one... another way is to clamp between 2 thicker sheets cut to profile & drilled for pins. Holes are used for registration. Then you can cut & trim without bending the shim.
Small blades can be cut from feeler blades - available in any car accessory shop.
Use a blind hole for riveting rather than a vise.

[benrains]

Thanks David. Very helpful. I figured out what a blind hole is, which definitely would be a better way to go (I had actually planned to hold the brass pins in a vise. :-)

[tmbg]

If you're unfamiliar with the word "shim" try google or Wiki perhaps.
Various thicknesses available (from a couple of thou') in plastics, brass, stainless etc.
Laser cutting is easiest & is accurate but expensive unless you own one... another way is to clamp between 2 thicker sheets cut to profile & drilled for pins. Holes are used for registration. Then you can cut & trim without bending the shim.
Small blades can be cut from feeler blades - available in any car accessory shop.
Use a blind hole for riveting rather than a vise.

Hahaha it's actually way less expensive to laser cut stuff when you DON'T own the machine. Those things are not cheap, and the maintenance is priced accordingly.