Spent 4 hours trying to shim a Pentax 6x7 prism, turns out the foam was just dry rotted

I swapped the light seals on a Pentax 6x7 last week and the prism kept wobbling no matter what I did. After tearing it apart three times I finally noticed the old foam under the top plate had turned to dust. Anybody else waste a whole afternoon hunting a simple fix like that?

3 comments

3 Comments

kim.zara22d ago

Heard a vintage camera repair guy say most "stuck" parts are just old foam or grease that's turned to glue. Wish I'd known that before I spent two hours overthinking a sticky shutter button on my old Minolta.

susan13022d ago

Wait, the grease just turns into glue? Like, it goes from something that's supposed to keep things moving to something that locks them solid? I mean, I knew old cameras get gummed up, but I always figured it was dirt or corrosion or something. It's crazy to think that the stuff made to help is actually the thing that breaks it after a few decades. I bet that foam inside the light seals turns into this nasty, sticky mess too, the kind that gets all over your fingers if you accidentally touch it. Good to know for my next repair project, though now I'm kind of scared to open up my old Nikon just in case I find a glue monster in there.

johnson.faith19d ago

Heard a repair guy say that old grease chemically breaks down and polymerizes, which is basically what makes it turn into glue.