The Curta.org Bulletin Board

[Nigel Fraser Ker]

Another question...any thoughts on how best to clean the plastic crank? It is lightly soiled and I'd like to clean it but I don't want to cause any problems in so doing (e.g. I'm scared of using solvents for obvious reasons).

Thanks,
Nigel

[Jack]

The plastic used for the crank on later model Type I and Type II Curtas sometimes develops a "frosted" or "chalky" surface appearance. The cause for this is some airborne or hand transferred chemical. After several trials at removing the coating by a chemical wash or by applying heat, I have had no success. The only success I've had in eliminating the odd appearance was by buffing the surface with microfine polishing compounds or microfine polishing cloths.

Check out: http://www.micro-surface.com.

When polishing the crank, it is very likely that the red reversing band indicator paint will flake off. The white paint within the pointer on the top surface of the crank often flakes off, too.

To replace either the red or white paint, I suggest procuring small bottles of car touch-up paint. White is available from many automotive parts stores. The red needs to be a brilliant red...try the Audi or VW "Tornado Red".

You'll also need to get a small amount of automotive paint thinner. (Regular paint thinner from a hardware or home center store WILL NOT WORK!). Adding a drop of thinner to three drops of paint will thin the touch-up paint enough so that it can evenly flow into the corners of the pointer or around the reversing band.

You'll need a very small brush to apply the paint/thinner mix. Visit a hobby or handicraft store to find such a brush. The smaller the better. The good news is that if you do a sloppy job, the paint can be chipped off after it dries...just try it again.
_________________
Jack Christensen
Timewise
32 Old Barn Road
Hawthorn Woods, ILLINOIS 60047
USA
847-550-5052 (evenings)
curta.info@gmail.com

[Nigel Fraser Ker]

Hi Jack,

Thanks very much for this information.

Kind regards,
Nigel