Plastic gears. Safe cleaner? Safe lubricant?

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BernardL

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I have a Fujica GS645W. The frame spacing is becoming erratic. I know from a previous repair that the frame counter, shutter cocking interlock, etc... use plastic gears. And I suspect that the original lubricant has dried, causing the frame spacing problem. I don't know more about the material than "plastic" (white, translucent).
Questions.
  1. What would be a safe solvent for cleaning old grease. Isopropanol? Naphta? Acetone I presume to be unsafe.
  2. What would be a safe lubricant for these plastic gears?
Thank you.
 
BernardL said:
I have a Fujica GS645W. The frame spacing is becoming erratic. I know from a previous repair that the frame counter, shutter cocking interlock, etc... use plastic gears. And I suspect that the original lubricant has dried, causing the frame spacing problem. I don't know more about the material than "plastic" (white, translucent).
Questions.
  1. What would be a safe solvent for cleaning old grease. Isopropanol? Naphta? Acetone I presume to be unsafe.
  2. What would be a safe lubricant for these plastic gears?
Thank you.
Click to expand...

As an ex- watch repair guy and ex- aircraft technician, alcohol is good and efficacious when used with a small brush (artist's kind).

White translucent could be hard nylon which, like most plastics, needs no lubricant.

Good luck!
 
The question of what lubricant to use, once the gears are clean, is key. Some lubricants can be absorbed by the plastic, causing it to swell and weaken. When I worked in the bike industry, we often encountered gears made of unknown plastics; for those, we standardized on silicone or PTFE (polytetraflouroethylene, say that fast, three times in a row, and conjure up demons!) lubes. Never any problems.
 
Retro-Grouch said:
The question of what lubricant to use, once the gears are clean, is key. Some lubricants can be absorbed by the plastic, causing it to swell and weaken. When I worked in the bike industry, we often encountered gears made of unknown plastics; for those, we standardized on silicone or PTFE (polytetraflouroethylene, say that fast, three times in a row, and conjure up demons!) lubes. Never any problems.
Click to expand...

I was about to say the same thing, and now I know what not to do when I'm irritated by some obfuscant piece of machinery... 😀

G
 
BernardL said:
You mean rubbing alcool, a.k.a. isopropyl alcool? what is your experience with dried lubricant?
Thank you.
Click to expand...
probably will require the services of a tooth brush and or tooth picks, it can be stubborn when dried hard. Soak in the over night, the beauty of alky is it is the least distructive of the cleaners. I have one of the super cleaners that I wrote "Not on Plastic" written all over it, learned that the hard way.
 
Darthfeeble said:
It's called "Goof Off" (honest!), there is also on my workbench another not quite as strong but will craze softer plastics "Goo Gone". Neither is recommended for use on anything camera related.
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We keep a little GooGone around the house for removing sticky labels. It's citrus-based. I'm glad to know it mustn't be used for plastics! Thanks!

When I worked in an electronics lab, we used 190 proof ethyl alcohol for cleaning circuit boards and such. It came in a big container, and was drinkable!
 
Rob-F said:
We keep a little GooGone around the house for removing sticky labels. It's citrus-based. I'm glad to know it mustn't be used for plastics! Thanks!

When I worked in an electronics lab, we used 190 proof ethyl alcohol for cleaning circuit boards and such. It came in a big container, and was drinkable!
Click to expand...
I was in Navy Air and the infamous "Torpedo Juice" found it's way into my life on one occasion. Another solvent is Naptha, famous for cleaning aperture leaves but I've never used it so I can't say it's good for plastic. Acetone will eat some plastics too, another poor choice for cleaning our gear.
 
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