I found a Mamiya 6 folding 6×6 RF camera at a camera show for $40.  Shutter working and Zuiko
75/3.5 (4 element) lens in clean condition.  Shutter speeds to 1/500.  I will show more of the camera
when I finish working on it.

The main problem:  a rather large hole in the bellows:

I tried a new method of patching.  On the inside I glued an oversize patch cut from black gaffer tape.
On the outside I applied many coats of a product called Plasti-Dip which I first thinned with naptha.
I let each coat dry for about an hour before applying the next until it all looked fairly well blended in.
The black Plasti-Dip matches the look of the bellows pretty well.  You have to look pretty closely to see
the patch.

I used a small paint brush to apply it and also painted it on the frayed corners of the bellows which
seemed to work well at sealing and strengthening them.

I haven’t tested with film yet (still working on some other areas) but it passes the flashlight test
and folds properly and is flexible and strong.

The Mamiya 6 was made in a number of different versions.  They are sturdy RF cameras with focusing
by moving the film plane forward and back via a rear thumb wheel. This makes it much simpler to
remove the lens groups for flood cleaning of the shutter if needed (not needed on this camera).

Whole forum thread is here