PDA

View Full Version : DIY Re-lacquering brass lenses



lungovw
8-Feb-2009, 17:20
Hello,

For those seeing vintage brass lenses more as current instruments than archeological findings, I uploaded one page where I describe a procedure for re-lacquering them. It can be homemade. The only less than usual things are the lacquer itself (but I give some tips about where to find it) and an airbrush, that doesn't cost a fortune and anyone can get good results with little practice.

Hope some of you will find it useful.

http://www.lungov.com/wagner/DIYBrassLensReLacquering.html

Best wishes


Wagner Lungov

Peter K
9-Feb-2009, 05:37
The problem with epoxi resin laquers is you will never get this special golden hue of old brass lenses. It looks always "restored". But if one uses the original laquer, collodion dissolved in amyl acetate - also called Zapon-laquer - one gets this special hue after some years.

Zapon-laquer can also apllied with an airbrush but it works with a brush too.

RichardRitter
9-Feb-2009, 05:44
Depending on the lacquer used the brass can go green in time under the coating.

IanG
9-Feb-2009, 07:09
Depending on the lacquer used the brass can go green in time under the coating.

Just like the way the first Ford metallic silver cars rusted through the cellulose lacquer (well in the UK & Europe anyway).

Richard is right some lacquers are actually very slightly porous to moisture. Acrylics are generally the best.

Ian

goamules
9-Feb-2009, 07:29
Thanks Wayne, I have been thinking of relacquering a couple of my lenses. I was also thinking the lacq used on brass instruments would be good. Yours look great. But I would like to hear more from Peter about the original process and chemicals. Where is amyl acetate found?

To me, polishing a brass lens has nowhere near the justifiable controversy of refinishing a gun or fine furnature (which one should never do). It's more like refinishing a fine classic car. Do you suppose whoever wins the rare Bugatti this month will leave 40 years of dust and rust on it? I don't think so. Also, sometimes the "patina" people are so agog about on a particular lens is actually fairly recent, forming after a previous owner polished off the original lacquer. If a lens has it's original lacquer, there won't be much "patina", only a mellowing of color, right? I was in the Navy, and we polished our brightwork before entering every port. Why? Because after weeks at sea an "ancient-looking" patina had formed. The point is an old brass lens may have been polished dozens of times over the years.

Anyway, some of my lenses have only portions of the original lacquer, with ugly splotches and green verdigris over large portions. To me, unless it's a rare lens like my Holmes Booth & Haydens, no harm is done by polishing and protecting.

My personal rules for not polishing are:
- A rare lens such as a Harrison Globe
- An uncommon or much older lens with any original finish
- A lens with 75% remaining original lacquer in decent condition

Can someone provide the definitive method used in the 1800s to lacquer?

Thanks,
Garrett

GPS
9-Feb-2009, 08:06
I would not recommend with a light heart to anybody a complete disassembly of old brass lenses or baking them on 150°C. Both has its dangers and in many cases is not possible. Old lens rings can be stubbornly sticked and demand very special care to take off the lens. You never know what kind of shims (sometimes primitive) you disturb, what kind of tension you induce with the heating etc. Unless the lens needs internal cleaning it's always best to let it be in one piece. Sorry for the b moll.

Peter K
9-Feb-2009, 08:44
Can someone provide the definitive method used in the 1800s to lacquer?
Since Christian Friedrich Schönbein's invention of the nitrocellulose, 1846, many things where made from this. E. g. the flexible base for photographic materials. So it's one of the first "plastic" widly used. Also as mentioned before solved in amyle acetat, alcohol and aether or acetone as laquer for metals, wood and paintings. And also used in medicine to close small wounds.

But be carefully, the solution is highly inflamble and explosive!

Peter K

BarryS
9-Feb-2009, 08:51
I bought a can of Staybrite Brass Lacquer (http://www.woodcraft.com/product.aspx?ProductID=13B55&FamilyID=3260) and I'm planning on using it to lacquer some brass camera parts and possibly a few lenses. I pretty much agree with Garrett's guidelines for refinishing lenses. I'll be trying this on a couple of magic lantern lenses to see how well it works.

lungovw
9-Feb-2009, 10:57
Thank you all for your comments. I will append most of them to the page and make it more informative.

Rgds

Wagner

Gordon Moat
9-Feb-2009, 13:30
On my HB&H the only thing I cleaned up was the mounting flange, since that had some very sticky substance on it. I like the brownish patina, which does not adversely affect the operation of the lens. The optics are perfect and clean.

On my old Zeiss Tessar 21cm f4.5 that lens is black finished. I did apply some white out to enhance the numbering for the aperture adjusting ring, though the lens is otherwise un-restored. I had debated polishing the lens, and decided against it.

An old lens, like an unrestored car, is original once. After restoration, it is a different thing, which some will see as better, and a few will see as worse. As an old Bugatti with low miles, it would be tempting to simply clean it up and not restore it. There is at least one old Ferrari 250 GTO still used in vintage racing that has been steadily maintained, but never restored. Whether something is better restored or original is something more of personal taste, though sometimes the buyers market dictates one choice over another.

Ciao!

Gordon Moat Photography (http://www.gordonmoat.com)

Pete Watkins
9-Feb-2009, 13:33
I really hoped that I'd never have to explain all this again, but................
I trained as a clockmaker in the 1960's. I worked in a small clock factory in the Clerkenwell Road, this was the clock / watch making centre of London at that time. The factory produced 50 English Fusee Dial clocks and a number (depending on orders) of Time Recorders (clocking in clocks) a month. The brass parts of the fusee clocks (not the friction areas) were laquered in the traditional manner, that is hot laquered with a shellac based laquer. The colours of these lacquers were varied by including different ingredients that could change the laquer colour from gold to green tones (God knows why anybody would want green, but there you are). We heated the brass parts up, one at a time, on an old clock dial placed over a gas ring and when we judged the parts to be hot enough we brushed the laquer on to the brass using a brush that was sold to us as a "camel hair brush" (a little ol' health and safty tip, the brass will be hot, very hot). I have a lens made by the London Lens Company (if you look that up and get a result let me know). The hot gold laquer applied to this lens somtime between 1865 and 1880 is virtually perfect. I once repaired a clock from Eastleigh Locomotive works that had been in the works for 50 years (we were good in those days, and we made things) and the laquer was perfect.
You are not going to get the results that they got in the past with cellulose laquers made for the auto trade, but they are very handy and I've used them on lens boards, but I'm old and don't care if the laquered finish dosn't last for 50 years. Last comment, there is NO gold in gold laquer. If any of you are masochistic enough to want to make yourself some "hot" laquers I might be able to find the odd (bloody odd) formula.
If I've been a boring sod, or p......d on anybodys bonfire, I'm sorry!
Best wishes,
Pete

lungovw
9-Feb-2009, 14:36
Hi Pete,

Thanks for explaining it again. First time I see it. I am highly interested in your bloody odd formula! Is that with Dragon's Blood? I commit myself to try it and publish the results in this forum (if I ever find the ingredients, of course).

Rgds,


Wagner

Pete Watkins
9-Feb-2009, 14:54
Wagner,
Give me a bit of time for research, I'll get back to you. The books are "somwhere".
Pete.

Struan Gray
10-Feb-2009, 03:31
If I've been a boring sod, or p......d on anybodys bonfire, I'm sorry!


You post was brimful of punctum. Not only do I have fond memories of creating supreme bafflement by going into a camera shop here and, in my halting Swedish, asking for a "Camel Hair Brush". The fact that I had dutifully looked up the Swedish for "camel" ("Kamel" :-) did not help at all.

And then there is the fact that my grandfather briefly worked at the Eastleigh Locomotive works - before moving to the much more sexy job of making Supermarine Seafires nearby.

And then there are my two big hundred-year old brassies. A pre-Dagor Dagor and a Suter aplanat, both of which look like they were engraved and lacquered yesterday, although the matt finish and colouration tell you they can't have been. In proper storage, classical lacquers do seem to last forever. It would be nice to know how they were done.

FWIW, I also have a hundred-year-old Zeiss "comet spotter" telescope. Here the lacquer is intact, but the underlying brass has turned a wonderful greenish-black. Although used for outdoor observing, the scope has been looked after well since purchased new by my wife's grandfather, so it's worth noting that a good manufacturer and classic lacquer is no guarantee of a long-lived shiney gold finish.

GPS
10-Feb-2009, 06:02
This section is from the "Handicraft For Boys" book, by A. Frederick Collins. Amazon: Handicraft for boys./p>

Lacquering Brass and Copper

To lacquer a brass or a copper article dip it in a weak solution of sulphuric acid and water and then wash it in clean water. Next put the article on a piece of sheet iron and heat it over a gas jet or in an oven.

It must not be heated enough to color it but just so that when you place your moistened finger to it it will sizzle; now put on the lacquer and this can be done by brushing the article over with a camel's hair brush or by dipping the article into the lacquer.

How to Make the Lacquer
Put 1 ounce of tumeric powder, 2 drams of annatto and 2 drams of saffron into 1 pint of alcohol.

Let it stand for a week or 10 days and shake it often; pour the clear liquid into a bottle and put in 3 ounces of yellow shellac; let it stand for a couple of weeks more; shake it often and pour off carefully. Then you can put it on. Lacquers can be bought ready made from Hanson and Van Winkle, Dealers in Electroplating Supplies, Newark, N. J.

Perhaps this would do?

Pete Watkins
12-Feb-2009, 03:02
Thanks for your kind words Struan. GPS the formula looks very usable. I only made some of this stuff once (about 25 years ago) because it was always available over the counter. I've found one formula from 1884........here we go, Take 2 ounces of the best pale shellac and add this to one quart of spirits of wine (Methelated Spirtis). Mix without heat by continuous agitation for five or six hours (I think that i shook it up now and then but over a period of a few days). If it's not clear it can be filtered. Do not leave it in a bright light. Here's a quote from the book "It may be coloured for yellow tints with tumeric, cape aloes, saffron or gamboge, and for red tints with annato or dragon's blood". Good luck in your quest for dragons blood, none of our local supermarkets stock it :-) We didn't acid dip parts to be laquered, they were all grained using emery paper in a lathe or using linishing machines. Pendulum bobs were polished on a polishing lathe.
Best wishes,
Pete

ic-racer
12-Feb-2009, 11:05
Reason for the heat is so that it 'flows out' when brushing, right??

So, if you are spraying, the retarder will do the same, right??

Pete Watkins
12-Feb-2009, 11:33
Sorry ic-racer, you need the heat to set the shellac. The laquer is brushed or sprayed on the hot (140 f) metal and it becomes hard on cooling. If the work is too cool the laquer will have poor adhesion. This comes from Cannings' Handbook on Bronzing, Metal Colouring and Laquering published in 1960. I've never heard of a retarder being used with hot laquer, it's a very old process.
Pete.

lungovw
12-Feb-2009, 11:34
Thanks Pete and GPS,

I will try out your formulas and post the results here as promised. Give me a couple of weeks.

Rgds

Wagner

ic-racer
12-Feb-2009, 17:11
Sorry ic-racer, you need the heat to set the shellac. The laquer is brushed or sprayed on the hot (140 f) metal and it becomes hard on cooling. If the work is too cool the laquer will have poor adhesion. This comes from Cannings' Handbook on Bronzing, Metal Colouring and Laquering published in 1960. I've never heard of a retarder being used with hot laquer, it's a very old process.
Pete.

Ok, for shellac based lacquer that makes sense. I was thinking of nitrocellulose based, but that's probably not what was used by lensmakers back then.

ic-racer
12-Feb-2009, 17:16
The reason I am asking is that I have experience spraying nitrocellulose lacquer for vintage guitars, but I have this little guy that I need to deal with. So maybe I need to learn a new technique. I guess I would need a source of that type of lacquer. I know where to get shellac chip.

Pete Watkins
13-Feb-2009, 02:31
ic-racer,
I've never re-laquered a lens but I have made brass lensboards for my Wista all I laquered them with was cellulose spray laquer from the local car parts suppliers.
It's lasted a few years now, but the boards don't get overused.
Pete.