View Full Version : Refinishing brass on old lenses

Steven Tribe
14-Mar-2013, 05:39
This has been discussed before - mostly in terms of when "intervention" is necessary.

There is a lot to be said for doing nothing unless there are signs of real corrosion.
Anyway here are some results of doing up 2 lenses, that in my view, deserved some attention.
The first was a Dallmeyer 3B - first design. In theory, this should have the traditional engraved brass sleeve, a Waterhouse cut-out and the usual tangential drive. These are often found with the drive removed. This one had lost the complete sleeve. It just had a section of the sleeve remaining with the thread for the flange. It had been soldered to the lens barrel proper. Not an easy job, as there is a gap between two brass pieces.

The first photo shows the lens as purchased. The leather item at the flange end I thought might be some kind of gasket between the barrels, but it turned out to be a very well-made safety strap to make sure the studio assistents didn't loose the lens onto the floor! Well worth keeping!

The current condition was 50% rough black paint and 50% very brown brass. Under the leather strap was a complete set of deep scratches which had obviously been made to make a good receptive surface for the solder.

I choose the compromise of a black enamel ring at the damaged end, combined with clear lacquer on brass on the section where a reasonable finish to the brass surface could be made.

Started with wet/dry paper (400) and finished up with (600). Then with Brasso (or equivalent). Polishing will not remove the residue even though it looks clean, which has to taken off with a non-instantly evaporating solvent. It is essential that all surface treatments involvement absolutely perfect rotation aroung the barrel.

In this case, the black ring was made first, followed by clear gloss spray everywhere. I use the most "old-fashioned" commercial spray I can get hold of. Check that the lacquer will not make the black paint bubble up. I prewarm the brass a little and use the kitchen oven (up to 50 deg C.) to speed up the process.

The last photo shows a much smaller Petzval sleeve. The larger lenses are more difficult to clean - as it is far more problematic to keep the movements parallel with the ends.

Jim Fitzgerald
14-Mar-2013, 07:02
Steven, thanks for this. They came out great!