Mamiya 645 Prism Repair

[thuggins]

I have several Mamiya 645 prisms with desilvering issues. I'm starting out trying to fix the unmetered one. I got the rear screws and release knob removed and the back end is free. But there something still holding the cover in the front. The metered prisms have screws in front, but this has none that are visible. I removed the leatherette and there's nothing under there.

Any ideas on how to release the front of the prism cover?

 

[Mamiya_Repair]

The front glued on nameplate needs to be removed to access the attaching screws.

 

[thuggins]

Thanks! I figured it was something like that, but didn't want to pry on anything too hard. Fortunately, I found an exploded diagram that showed the badge was in two pieces. The frame/bezel is a casting that is held with screws. The nameplate itself is a stamping that is glued into the frame.

I came across this Rustoleum Mirror Effect paint and decided to try it for repairing the prism. It's not perfect, but it works pretty well. Clean the damaged area with acetone to remove any residual silvering and spray on the paint.

 

[thuggins]

Here's what it looks like. A heck of a lot better than a big, grody spot in the center of the view. The blending at the bottom isn't perfect but I think that could be remedied by rotating 180 degrees between coats. The thin, horizontal line thru the middle is a mystery. I don't think it was there before, but maybe I just didn't notice.

Here is another that shows the blending better.