Compur Rapid speed escapement just won't clean

[Bunnyblaster]

So a buddy picked up an old 1930s Welta folding rangefinder with a Zeiss 2.8 and Compur Rapid shutter. He gave me an RB67 kit in return for bringing the Welta back to life. I know. Good deal.

But I've tried nearly every solvent I can find to clear up that escapement, and it's still sticking. Lighter fluid, 91% alcohol, a rifle bore cleaner called Butches Bore Shine, carb cleaner, starting fluid, etc. A whole lot of soaking and a whole lot of flushing. She still hangs up on 1/5, 1/2, and 1 sec.

Any ideas on a better solvent? Acetone? I read benzene was great, but I've got no idea where to find that. Supposedly it's in some carb cleaner, but not the stuff I've got.

Appreciate any ideas. Shes soaking in more carb cleaner now (just the escapement).

 

[Bunnyblaster]

Huh. That's a good idea. Have one of those I use to clean rifle brass. What would you suggest using as the cleaning solution?

 

[paul ron]

Did you lubricate the shutter? Here's the repair manual....

http://benoit.suaudeau.perso.neuf.fr/manuels_rep/obturateurs/Compur-shutter-repair-manual.html

 

[shutterfinger]

Huh. That's a good idea. Have one of those I use to clean rifle brass. What would you suggest using as the cleaning solution?

Your 90% Isopropyl Alcohol should work just fine. If its disassembled try lacquer thinner on the subject part only. Lacquer thinner will strip the bluing off the shutter and aperture blades as well as any protective coating on the other parts and the case finish. I've sometimes had to scrape the grease residue off some parts. Grease is a soap base with oil. Some soap bases will dry out to the consistency of mortar.
Some shutters are badly worn and will not work properly at one or two speeds regardless what you do. In those cases you have to adjust for the best overall operation.

 

[02Pilot]

Are you absolutely sure that the escapement isn't damaged? A slight bend in one part or another could be at fault.

 

[John Koehrer]

In some older shutters one adjustment was by pivoting the escapement. It didn't take a lot to
hang up a couple, but not all the speeds.

 

[paul ron]

Looks like the op is gone.

Compur shutters don't run dry like a lot of others. There are certain parts that have special coatings from the factory that should not be removed when wet cleaning. Also no matter how clean you get that shutter, it will never run properly until you lubricate it according to the manufacturer's recommendation.

Read the repair manual?

 

[Bunnyblaster]

Sorry. I was out for a couple days. Self employed media producer and had some work pop up. Take it when I can get it.

Thanks for all the help so far! Last night I put the escapement inside a small glass jar of 91% isopropyl alcohol and placed that jar inside my ultrasonic cleaner full of water. Ran the thing for two durations of 20 min each. Still no go. It actually got worse. Maybe something is breaking loose in there, I don't know, but I can't see any sign of gunk in the escapement through magnifiers.

Thanks for the link to the manual, I'm working on viewing it now. For some reason, my web browser didn't like it. Before I put it back in for another test I'll be sure to follow their lubrication directions.

It wouldn't surprise me at all if its clean, but something else is the issue. Lubrication, adjustment, etc.

 

[shutterfinger]

In the manual link above the lower set you download to your computer and install DJVU then read the documents without being on line. I have both the DJVU version and a print version I bought years earlier.
I doubt your shutter is in that manual However you may find that the shutter blade timing and cocking/release matches one of the other shutters while the aperture system matches a different shutter. I have repaired a few Compur shutters that way. The lube guide shows where to put the Compur lubricants with colored lines along the surfaces. It leaves a lot to be desired.

The delay uses a coil tension spring. If the operating arm disengages with the gearing the spring tension has to be reset. 1 gear tooth makes the difference between all speeds being good or only some being good. The strength of the main cocking spring plays an important role in how accurate the speeds are also. There is a tension spring on the delay pallet that may need to be set to a different position to get the delay to work correctly.

I have a good working Compur 00 I will be listing for sale on the auction site in a few days if you are interested.

 

[Bunnyblaster]

Really appreciate all the info here. Got a chance to adjust the main tension spring on the cocking lever, lubricate the different areas within the speed escapement and a couple small friction points within other parts of the shutter. Today she's running like a champ. I haven't timed the speeds, but they don't hang up and sound close.

 

[paul ron]

That's good to hear. She's a beauty!