View Full Version : Cleaning and restoring a brass & steel lens

28-May-2008, 09:40
Anyone having read this thread http://www.largeformatphotography.info/forum/showthread.php?t=35721 , know which lens I am talking about - a 22lbs Petzval (aka "The Stove Pipe") painted flat black by a previous owner. Yes, the look hurts the eye, and I've decided to return it to it's former shine and glory. The paint came off alright, but the brass and stainless steel (?) underneath are heavily tarnished with plenty of discolourations, blotches, oxidation spots, and dark "scratch" marks. I got some of these out or at least diminished, but it's still far from perfect. Any hints?

And while we're on the subject ... does anyone know how to take the inner tubes of a 4A B&L Portrait lens apart (or a 3A)?

Thanks, Chris

Glenn Thoreson
28-May-2008, 17:24
If you don't have a good buffing wheel setup, it just involves a lot of rubbing. My method - start off with number 0000 steel wool and rub until it looks clean and shiny. Next, rub it well with a soft cloth and automotive rubbing compound until you get any signs of fine cleaning marks off. Water the compound down a little and keep rubbing until you get the desired mirror finish. Clean very well with a damp cloth and spray with clear lacquer to prevent oxidation. It's a lot of work, but the results can be very satisfying.

28-May-2008, 17:35
Hi, Ben.

Take a look the the two lenses in my avatar photo. They started out as a grossly tarnished mess. I had a friend who repaired brass musical instruments. I took the glass out and handed him the barrels. A few days later, after soaking them in some witches brew of solvents that he used, he had them buffed to a high gloss and lacquered beautifully. Three decades later they are still perfect. If there's a music company in your town that supplies the local schools, they should have a repair guy on site or under contract that should be able to help you.

Good luck.


Paul Fitzgerald
28-May-2008, 18:09
"And while we're on the subject ... does anyone know how to take the inner tubes of a 4A B&L Portrait lens apart "

Let the air out first.

Actually, most of the old brass lenses were NOT mirror polished when new but had a brushed finish. The easiest way to duplicate this is to use:

3M 'Sand Blaster' 400 grit pads.

They are purple, foam rubber netting, and available at Ace hardware. You will see the netting look on sight. They leave a perfect brushed finish easily BUT be careful moving the pad or you leave slide marks.

For a mirror polish try 'Mother's Mag and Aluminum polish' and a soft paper towel, it will build a mirror polish on brass in about 30 seconds. When it turns black, wipe it off and check your progress.

If you can set-up a turning spindle to hold the parts it would make the job a whole lot easier.

Have fun with it.

28-May-2008, 20:23
"And while we're on the subject ... does anyone know how to take the inner tubes of a 4A B&L Portrait lens apart "

Let the air out first.

Have fun with it.

Ahem ... it's the air thing :rolleyes:; I probably should have used the term "barrel" or "pipe", but didn't find the right word at that moment. Anyway, the problem with said lens is less the air inside;) , but the fact that it consists of no less than three barrels stacked inside each other - the outer sleeve with the focussing knob, a middle one which holds most of the elements (almost like any other period lens), and finally a inner one which controls the softfocus element. Plus there appears to be a number of moveable plates, since the knobs for setting the aperture and softness are located on the outer barrel with thin covered slots only (not the huge cutouts as seen on other 19th century lenses). In short - it's a mystery to me:confused: .


PS: polishing the brass by hand is a painful exercise indeed; I am afraid that by the end I am going to look like Popeye:eek:

29-May-2008, 06:37
Get your self a Dremel type set up and some jewelers rouge and have a go at it , Of course after you give it a general cleaning: Black fingers are the norm for this kind of work:

al olson
29-May-2008, 09:19
If used carefully I would think Brasso would work. They carry it at my local Ace store. I believe I have also seen it on supermarket shelves.

Jim Galli
5-Jun-2008, 15:43
How're you doing on the tubes?

Go to the auto parts store and buy a product in a pint can called "rubber buffer". It is tri-chloroethylene and will penetrate and remove a century of dirt as you work it a bit. Great stuff. Leaves no residue. Probably causes cancer and depletes the ozone, but hey, it's a petzval!

John Schneider
5-Jun-2008, 17:42
Yikes, trichloroethylene has some unpleasant side effects beginning with arrhythmia and continuing on to kidney cancer and neurotoxicity. I work with chemicals in the lab and personally I'd much rather wash my hands in xylene than handle trichloroethylene. My recommendation is to use kerosene and some patience. Kerosene will soften decades of crud if you soak it or spread it on and then wait for the residue to soften, wipe and then repeat.

Glenn Thoreson
5-Jun-2008, 18:52
I use liquid buffer (Trichlorowhatzit) to clean shutters. In my younger days I repaired about a bazillion tires using it. I ain't dead yet. Of course at my age, it probably doesn't matter what the cause. :D

5-Jun-2008, 19:11
Hi all.

The general cleanup went well - looks pretty good now. Have to replate the nickel plated portion though; but that give me a good excuse to buy more stuff:D (a small Caswell plating kit should do).
The brass tubes could need a cleanup internally; I haven't decided on the method yet. Disassembly is not a option at this point (reason: lack of knowledge how they put that thing together in the first place).
The aperture is a bit stiff; will probably try some graphite first.

Anyhow, I'll keep you guys updated as work progresses (still have to figure out how to mount that beast securely).

EuGene Smith
23-Jun-2008, 09:02
"still have to figure out how to mount that beast securely"

Don't know what you call 'em, but I got one of those iris-looking things for $10 at a camera show about 5 years ago, and it's perfect to clamp around a barrel lens to hold it. It has a knob to close the heavy blades around the barrel and make a light tight seal (just to be sure of the seal, I wrap a strip of cloth around the lens, then clamp it). A second knob locks it in place. The lens holder opens up to about 3" and with its heavy blades it wouldn't have any trouble securing a lens weighing several pounds.