Help Please...Film Debris in SR3 Mag Throat after Testing

[Karl Lee]

Hi all.

I hadn't had my SR3 fully assembled and running in nearly two years, so I thought I'd get it out, run some practice film through the mags, and put it through its paces...kind of like periodically running a car that is in storage.  Anyway, all appears to be well mechanically, but after running 300' or so of practice film through one of the mags, I noticed accumulation of debris in the throat of the mag, and a bit of black sooty material on the pressure plate.  The material accumulated in throat seemed to have the consistency of carpet lint, but I'm pretty sure it's extremely thin, curled shavings of film. 

Any thoughts on whether this indicates an issue with the mag, or could it be simply due to practice film that's past its prime?  My practice film is some older EXR, and while I've used it sparingly before (maybe running 30' or so through just to do a scratch test), this time I ran nearly 300' through the mag, and even ran the camera at 48 FPS for a minute.  I've never had an issue with this mag before, and I'm hoping that it's just an issue with film that I shouldn't be using anymore, even for testing.  On that note, what's the best source for acquiring some new-ish test film?

Thanks to anyone who might be able to help!

 

[Dom Jaeger]

I'd say it's likely due to the old film being brittle and not flexible enough to twist across to the gate. The shavings look like they are coming from the top gate hook, which does exert pressure on the film edge.

Try some fresher stock and see what happens. Make sure the loop is the right size and properly centred as well.

[Robert Hart]

When you loaded the mag, which side of the roller did the film end go? With both remjet backing and film emulsion shaving off, this suggests to me that the film may be feeding past the opposite side of the roller and dragging across the case. This happens in CP16 magazines if one is not careful when loading film in the dark.