Historical Formula for Relacquering Brass

[CCHarrison]

For those of you interested in putting a lacquer back on lenses that have had their lacquer removed....

From the Feb 1872 issue of The Photographic World:

82212

Dan

[Fotoguy20d]

Interesting, and tempting. But, I'm not sure it's something I want to try in my kitchen. Thanks for posting it.

Dan

[E. von Hoegh]

This is a pickling formula for preparing the surface before applying lacquer. It sounds like a recipe to give a gilt-looking finish. If anyone decides to try it, stay well upwind of the fumes given off and make certain there is nothing breathing downwind as well.

I've had very good results just graining the surface with degreased 0000 steel wool and applying the lacquer while the piece is warm. I used a blob of cotton wrapped up in some light cotton bedsheet fabric as an applicator, the heated part was held in a lathe and turned slowly for application.
It takes decades to get that glowing look as the lacquer ages.

[Jody_S]

Hmmm... I'm not aware of any consumer products containing Nitric acid (much less red fuming). I wonder if Hydrochloric acid could be substituted?

[goamules]

I keep wanting to learn the actual, no kidding, lacquer process and materials used in the 1800s, for the occasional battlefield dug relic lens. I know the golden color was a result of dye additives used back then, and each manufacturer had different colors. Voigtlanders had almost clear lacquer. Dallmeyers had a slight golden tint. Darlots can be glaringly orangish yellow.

This guy did a pretty good job, with organic dyes and shellac. http://www.lungov.com/wagner/DIYBrassLensReLacqueringOldWay.html But somewhere there has to be a period article or manual explaining what they used. Shellac? Lac? Put on hot? baked? The quality control in the 1800s was amazing, I've never seen a drip run, thick area, or other problem on any lens that I recall.

[E. von Hoegh]

hmmm... I'm not aware of any consumer products containing nitric acid (much less red fuming). I wonder if hydrochloric acid could be substituted?

no!

[goamules]

Here is an example of the lacquer color used in the late 1880s by Darlot. I received it mint, in the original box, and think the color represents what they looked like new pretty accurately. I'm not convinced lacquer "ages" or "mellows" or changes colors at all. Anyway, notice the strongly tinted red-yellow color.

http://farm6.staticflickr.com/5128/5201996687_2d1097634d_z.jpg

http://farm5.staticflickr.com/4128/5202589948_6d04036e57_z.jpg

http://farm5.staticflickr.com/4151/5202589954_702743ec1a_z.jpg

http://farm5.staticflickr.com/4133/5202589940_d79478ac0c_z.jpg

[E. von Hoegh]

I keep wanting to learn the actual, no kidding, lacquer process and materials used in the 1800s, for the occasional battlefield dug relic lens. I know the golden color was a result of dye additives used back then, and each manufacturer had different colors. Voigtlanders had almost clear lacquer. Dallmeyers had a slight golden tint. Darlots can be glaringly orangish yellow.

This guy did a pretty good job, with organic dyes and shellac. http://www.lungov.com/wagner/DIYBrassLensReLacqueringOldWay.html But somewhere there has to be a period article or manual explaining what they used. Shellac? Lac? Put on hot? baked? The quality control in the 1800s was amazing, I've never seen a drip run, thick area, or other problem on any lens that I recall.

Look in the 11th edition Encyclopaedia Brittanica.

Don't forget that different brasses have different tints, and the surface treatment will affect the color a bit as well.

That's not QC but craftsmanship. :)

[Drew Wiley]

Shellac can be made up in all kinds of color variable depending on how bleached it is, from
pale yellow to orange. It's alchohol soluble. Despite shortcutting authenticity, you might
want to substitute a fine nylon woven abrasive like white Scotchbrite for steel wool. Those
little steel fragments get into things and rust. I once sold the eight gallons of shellac which was used to cement the correction lenses into their mounts for the Hubble space
telescope. It's a pretty remarkable substance with no synthetic counterpart. You can test
for it with a simple strong alcohol swab on a Q-tip. It's soluble.

[John Schneider]

Spill that fixture and wipe it up with a cotton rag and you've just made guncotton.

I doubt that just anyone could purchase RFNA, as it is extremely corrosive and oxidizing.

RFNA reacting with nitrile gloves: http://www.youtube.com/watch?v=OjtF-lRkgME

[E. von Hoegh]

Spill that fixture and wipe it up with a cotton rag and you've just made guncotton.

I doubt that just anyone could purchase RFNA, as it is extremely corrosive and oxidizing.

RFNA reacting with nitrile gloves: http://www.youtube.com/watch?v=OjtF-lRkgME

The article says "nitrous" acid, but describes RFNA which isn't that difficult to make. No, I won't describe how. Don't breathe the red fumes unless you like lung edema. Don't leave it exposed to sunlight either.

[Drew Wiley]

Maybe someone should tip off Homeland Security before this goes too far ....

[Steven Tribe]

Apart from shellac types, clear celluloid disolved in alcohol (takes time) gives a good finish.
It was recommended to prepare a yellow and a red stock solution and mix to obtain the desired hue.
Applied to warm (not hot) brass.

[Jim C.]

Here is an example of the lacquer color used in the late 1880s by Darlot. I received it mint, in the original box, and think the color represents what they looked like new pretty accurately. I'm not convinced lacquer "ages" or "mellows" or changes colors at all. Anyway, notice the strongly tinted red-yellow color.


I think I wet myself !
Superb lens specimen !
:)

[domaz]

Isn't Nitric Acid commonly used by Wet Plate photographers? B&S (http://www.bostick-sullivan.com/cart/home.php?cat=427) seems to have it at least in 7% form. Not saying it's safe but it is obtainable.

[E. von Hoegh]

Isn't Nitric Acid commonly used by Wet Plate photographers? B&S (http://www.bostick-sullivan.com/cart/home.php?cat=427) seems to have it at least in 7% form. Not saying it's safe but it is obtainable.

The lower concentrations are "relatively" safe. The red fuming variety is nasty! It's not too hard to get.

[tamasflex]

Other formulas for lacquering Brass:

http://chestofbooks.com/crafts/mechanics/Workshop-Receipts-3/Lacquering-Optical-Work.html#.UXVxE6KBkaO

http://chestofbooks.com/crafts/mechanics/Workshop-Receipts-5/Lacquers.html#.UXVxo6KBkaN