Thanks for your comments. Iím trying to get speeds between ľ secs and 2 secs, in some Russian TLRs (Komsomolets and Lubitel 2). The Lubitel 2 has speeds above 1/15 and the Komsomolets has speeds above 1/25, and I want something slower. My idea was to take a working shutter from a dead camera and connect it to a cable release (no electronics involved); Iím not looking for a very high degree of precision, but Iím not so experienced (yet) as to be able to keep a shutter open within the range of speeds I mentioned. My options seem to be either a) find/build a device to do it or b) spoil a lot of film while I learn to do it on my own ...
Thanks again