sonic cleaning a mechanical shutter unit

[EdwinV]

I am cleaning a TLR mamiya 80 mm lens and was wondering if it is safe to sonic clean it, using a ultra sonic cleaner that you normally use for jewellery and watches. Not just the slow gear escapement (which i cleaned wiht lighter fluid but it is simply is not clean enough). So i was thinknig in drowning the whole thing (without the glass ofcourse, just the bare shutter mechanism with the aperture blades) in the ultrasonic cleaner.
1. Anybody has any experience with that ?
2. What cleaning solution to use then
3. If not recomnended.... why would it not work ?

 

[Highway 61]

I have done it once. Whole shutter unit, which was very dirty and corroded. Worked very well and didn't damage anything. The solution was isopropylic alcohol (99%).

The issue is with the further step, which is the drying once you take it out of the ultrasonic tube. You must have a pure nitrogen blowing compressor at hand, to prevent any further corrosion, which may happen if dried with air.

 

[Mr_Flibble]

I've done it a few times with leaf shutters, like Compurs.

I used either water with a small drop of detergent or naphtha/white gas depending on the contaminants I wanted to remove; grease, oil, WD40



Making sure all the liquid/moisture gets out of the mechanism afterwards as suggested above to prevent any corrosion. Particularly between the shutter and aperture blades if you left those in!

 

[Dan Daniel]

1. Anybody has any experience with that ?
Yep, do it all the time.

2. What cleaning solution to use then
I use naphtha. I put the naphtha in a small jar which. this sits in the cleaner that has plain water in it. Putting the shutter and cleaner in a jar gives me two things- I am not sloshing a flammable liquid around when filling and emptying the cleaner. And I have a 'safety catch' in case parts I didn't realize were free drop out.

When I get to small parts, I have a stainless steel tea strainer. One of those spring-loaded balls with a handle, very fine mesh screening. Drop that in a jar of naphtha, sometimes just on top of larger parts.

I have found naphtha is a nice balance between effectiveness, no residue, and safety to parts and paints.

I know someone who uses xylene for cleaning parts (not shutter blocks, only disassembled parts) but he has a firesafe exhaust system; xylene smells much more than naphtha. Xylene is more aggressive and will dissolve most paints.

To dry, I have a gas oven with a pilot light that is always on. The interior is always about 130F/55C. After using a hand air blower to get a bunch of fluid out, I put the shutter in the oven for a few hours. It's a slow deep heat that drives liquids out from inside nicely. You can tell by both any fluid on the blades and by the feel of the shutter ring itself if it has dried.

It is good to operate the shutter leaves and the aperture blades and wipe them down with cotton swabs when first starting the drying process. And most times I find i need to clean the blades after dried.

3. If not recommended.... why would it not work ?
Although I recommend it, it has real limits. Fluid and bubbles need to get into very small spaces. If old materials do not dissolve fully, the new sludge is as bad as the original sludge. Particles of dirt need to find their way out. So it is not a miracle cleaner. Sometimes you need to do it fully- disassemble and clean.

Especially if it seems that oil or grease have gummed up in the shutter blade ring- that part needs to be very clean, but it is deepest inside with little egress. It is meant to be a light tight assembly which means it is not welcoming of fluids.

 

[Muggins]

I wouldn't go near xylene unless you are a trained pro with professional level ventilation, extraction and protective gear. It's really quite unpleasant stuff to be around, being toxic via inhalation, skin contact, and pretty much every other route you can think of. On the eastern side of the pond you'll only find it in specialised labs.

 

[EdwinV]

This is all super helpful. I think i will go down this route.

 

[Dan Daniel]

I wouldn't go near xylene unless you are a trained pro with professional level ventilation, extraction and protective gear. It's really quite unpleasant stuff to be around, being toxic via inhalation, skin contact, and pretty much every other route you can think of. On the eastern side of the pond you'll only find it in specialised labs.

Yep. And yet you can buy it off the shelf in most any US hardware store. While naphtha is being phased out more and more. Go figure.