Simplest way to repair bellows?

[Grim Tuesday]

I have a Mamiya c220 with a few large-ish holes in the outer bellows. Of course, the secret to these cameras that the sellers on eBay don't know is that there's a second set of bellows for the taking lens, and the outer set is only for the viewing lens. So small holes in the outer bellows are mostly a non-issue. But nevertheless, they reduce contrast on the viewing screen so I'd like to take a shot at fixing them. I've reviewed past threads and most methods (smartly) prioritize light tightness. In my case I don't really mind if they're only 99% light tight, so long as they articulate well and I don't spend too much time or money messing around with them. With that in mind, what would be the simplest, cheapest way for me to repair these bellows?

 

[shutterfinger]

Pin Holes: Use Golden Heavy Body Acrylic Artist Paint #1040 Carbon Black diluted no more than 1:1 and paint from the inside in thin layers until light tight with a fine bristle artist brush.
Rips or tears: Bond black rip stop nylon to the inside with Pliobond contact cement then paint with Golden Heavy Body Acrylic Paint #1040 Carbon Black.
Diluting the paint helps it to flow into the inner lining. Water or Golden's mediums can be used to dilute the paint.

https://www.goldenpaints.com/technicalinfo/technicalinfo_hevbod

 

[John Koehrer]

Howz about black construction on the outside? Cut to the size of the fold in the bellow and glued only
to the flat section in the bellows. THIS STUFF WILL NOT FOLD.

If you would like to have some black bookbinders tape let me know & I can send you some.
Many people use this to repair hinges on DDS.

 

[nosmok]

This is tailor made for 3M 850 black polyester tape; it is expensive but one roll will last a very long time. Advantages: it will stick to the bellows easily, never come off, and add essentially no thickness to the bellows so it will fold and unfold just fine. Plus you don't have to wait 3 days for it to dry.

 

[AgX]

Pin Holes: Use Golden Heavy Body Acrylic Artist Paint #1040 Carbon Black diluted no more than 1:1 and paint from the inside in thin layers until light tight with a fine bristle artist brush.
Rips or tears: Bond black rip stop nylon to the inside with Pliobond contact cement then paint with Golden Heavy Body Acrylic Paint #1040 Carbon Black.
Diluting the paint helps it to flow into the inner lining. Water or Golden's mediums can be used to dilute the paint.

https://www.goldenpaints.com/technicalinfo/technicalinfo_hevbod

That data sheet states that the flexible acrylic film will loose its flexibility in the cold. Something not yet discussed here concerning repair paints for bellows.

 

[Grim Tuesday]

This is tailor made for 3M 850 black polyester tape; it is expensive but one roll will last a very long time. Advantages: it will stick to the bellows easily, never come off, and add essentially no thickness to the bellows so it will fold and unfold just fine. Plus you don't have to wait 3 days for it to dry.

So if I use a tape of some kind on a larger hole (1cm x 5mm), over a fold, should it be used as a patch or should I pinch the edges of the hole together and put tape over it? When I was thinking about it the patch makes sense but it leaves some stickiness exposed in the middle of the hole. Would this be a real problem or is it imaginary?

 

[shutterfinger]

That data sheet states that the flexible acrylic film will loose its flexibility in the cold. Something not yet discussed here concerning repair paints for bellows.

I use that paint in moderate climate. It gets down to 25°F to 30°F on occasion and I don't use cameras that were patched with the paint in those conditions but have opened and closed them with no more stiffness than one without the paint patch.

As for drying time, the paint drys in 30 minutes but I let it sit with the bellows open overnight for good measure.
I have coated several Graflex SLR shutter curtains with the diluted paint (3 coats) and there have not been any complaints form those living in the northern states where the temperature gets well below 0°F in the daytime about the shutters being stiff in the cold. I do not know if they take their cameras out in that weather or not.

As for tape, commonly available tapes dry out, shrink, and leave a sticky residue that is a PITA to clean up.
The tape referenced to in post #4 has been recommended by others in other threads for bellows repair. With the possible exception of it tape is a no no.