Mamiya C330S Pro Question

Someone gave me a C330S Pro that had been left sitting for a considerable period. When I looked inside, ONE wall of the four of the area between the lens (and the light door) and the film was whiteish-gray, while the other three were black with a sort of felt look. I was able to brush away a layer of the whiteish-gray material, and that wall was black again, but not as dark as the other three, and the surface had the appearance of sun-dried, muddy earth, with irregular "cracks" throughout the surface.

 

The material on those walls appears to be somewhat gummy and pliable. I looked at another C330 body, and the interior surfaces in that part of the camera were covered with a harder, black material with a different type of surface.

 

When I shot a test roll, specks appeared on the prints, which, of course, turned out to be additional material that had crumbled from the whiteish-gray wall on the camera's interior. If you rub that side, your finger will be slightly black, so it's flaking off.

 

How can this be repaired? Is there another material that could, perhaps, be laid over the top of the deteriorated wall? I'm really curious as to what's going on there, since it was just the one wall -- the entire wall, not just a part of it. The other three walls appear completely unblemished.

 

Thanks!

Mamiya subtly modified some of the materials used in the final iteration of their TLRs (330S and 220F). One of these modifications was the anti-reflective coating on the walls of the body chamber between lens and film. Ostensibly these were meant to be improvements, but as with Hasselblad's dreadfully ill-conceived "palpas" coating they do not age well, resulting sometimes in the issue you've described.

 

Earlier Mamiya TLRs simply used flat black paint, or a more durable rubber-impregnated (but well-sealed) coating applied directly to the chamber walls. The C330S and C220F have an updated, more obviously rubberized coating that is not directly applied: the coating is on separate, adhesive-backed sheets which are then stuck onto the walls (not unlike the way the black felt of the folding lens light trap panel is installed on every Mamiya TLR ever made). Unfortunately the newer sheet-based coating, while slightly more anti-reflective, is also slightly less durable. Over time it can develop the white mold-like surface you describe, which when rubbed off causes the substrate to crack and flake into powder.

 

I just checked my own 330S and 220F: neither has developed this issue with any severity yet, tho I did see a faint trace of white on one panel in my 330S which I brushed off carefully to no ill effect. My much older backup C220 is totally fine, since it has the simpler black paint finish.

 

If approached carefully, it looks like the issue might be DIY repairable. The deteriorated coating sheet could perhaps be peeled off and replaced with some other flat black sheet material, or painted. The bare metal wall under the sheet may in fact already be painted, in which case I would just leave it as-is unless it has any reflective patches. The top, left and right walls seem easy enough to resurface, but the bottom wall may be trickier due to the clearance needed for the folding lens mount panel (any replacement sheet would need to be thin enough for the panel to lie flat over in its normal "lock" position). Since the bottom is covered by the black felt folding panel in normal use, I don't think I'd bother resurfacing it after removing a worn coating sheet: it is redundant.

Thank you for this information. I was able to peel away the deteriorated sheet as well as the one adjacent to it, which suffered a little damage in removing the first (before I got he hang of it). The surface beneath is flat black, although with a couple of spots where hardware just barely pokes through from the other side. I need to touch it up a bit with some flat black paint. I do like the surfaces applied on the older Mamiyas a lot better.