How do I paint brass black?

Discussion in 'Camera Building, Repairs & Modification' started by veriwide, May 3, 2005.

  1. veriwide

    veriwide Member

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    I am starting my summer project. I have a J.H Dallmeyer Radip Rectilinear lens, Patent(US) date June 30, 1868, marked 21x25. I have tested, and my research agreed, that its focal lenght is 33 inches. I am plannning a falling plate 20x24 box (OK, crate) camera. I will start with paper negs, and I forsee with practice moving to film on down the road, as design changes and money afford.

    I have the shim stock in hand that I will be fashioning my waterhouse stops out of. I will be using standard drill bits sizes for my holes from 2 inch down to 1/64, which will give me working appertures from f16.5 to f1052.

    The question of the day is how do I paint brass black? I am looking for a process, or paint that will adhere to the brass shim stock after they are cut to size. I have a feeling that the smooth shiny surface would resist a normal paint. Any ideas?

    Thanks,

    Patrick Pitzer
    Boone, NC
     
  2. Donald Miller

    Donald Miller Member

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  3. Dave Parker

    Dave Parker Inactive

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    Make sure that any anti corrosion coatings have been removed from the brass stock, I normally use a very fine steel wool to remove the coatings, this will also burnish the surface of the brass for coating with the paint, I use a flat black stove paint, coat one side and bake in the oven for about 20 minutes at 225 degree's, let is set over night, then coat the other side and repeat the baking process, this normally gives a pretty good durable coat of black paint.

    Good luck

    Dave
     
  4. Aggie

    Aggie Member

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    One of our sponsors, Bryant Labs is also a producer of metal patina chemicals. Many of these will give you interesting colors on brass, and of course the standard black. Support a sponsor and call and find out what color you whight want your brass to be. They also carry a laquer that works well to protect the finish.
     
  5. bjorke

    bjorke Member

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    Or gaffer tape :smile:
     
  6. Gerald Koch

    Gerald Koch Member

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    Blackening brass

    For photographic purposes brass is usually blackened rather than painted. Paint does not adhere well to brass and tends to flake off. Make sure that the brass is clean and free from oil or grease. Even the oil from your finders will prevent good blackening. Rubbing with 000 steel wool will remove any oxidation. The blackening agent is a 10 - 20% sodium polysulfide solution.

    Jerry
     
  7. Loose Gravel

    Loose Gravel Member

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    I have tested many spray flat black paints. By far, the blackest one I have found is Krylon's Ultra Flat Black. A little hard to find. With the right primer, it will stick to most anything. Email Krylon for primer advice.
     
  8. JG Motamedi

    JG Motamedi Member

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    You can buy a brass blacker in most gunshops. This works very well for waterhouse stops.

    How about a picture of your monster lens?
     
  9. Ole

    Ole Moderator Staff Member Moderator

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    You mean - Viradon???
     
  10. Tom Duffy

    Tom Duffy Member

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    Let Leica do it. They did a nice job on my Millennium. :smile:
     
  11. Dave Wooten

    Dave Wooten Subscriber

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    would black anodized aluminum work or a black delrin type product, or cut it from an old black film holder septum or dark slide?






    or gaffer tape
     
  12. Greg Davis

    Greg Davis Member

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    I have used the Brass Black product before, and it works well. All of my lenses are attached to their lensboards using brass machine screws I treated with it. It comes out with a nice solid matte black color, especially after two coats. Since it's a stain, it doesn't change the thickness of the brass.

    -Greg
     
  13. veriwide

    veriwide Member

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    Here's the monster!! This is the first time I've tried attachments with this system, I hope it works.

    Patrick
     

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  14. Gerald Koch

    Gerald Koch Member

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    I don't see any reason why Viradon shouldn't work if you already had it or couldn't obtain the sodium polysulfide.
     
  15. Donald Qualls

    Donald Qualls Member

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    Yipe! Is that what they call a "55 gallon barrel" lens? :wink:
     
  16. bobfowler

    bobfowler Subscriber

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  17. bobfowler

    bobfowler Subscriber

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    I'm pretty sure you'll have to cut powder charges to use that thing! :smile:

    White bag! Charge 7!!!

    KA- BOOOM!

    hehehe
     
  18. Ole

    Ole Moderator Staff Member Moderator

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    I'm sure it's meant to use flash powder!

    Nice "Cannon", anyway :smile:

    Even bigger than mine!
     

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  19. Greg Davis

    Greg Davis Member

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    Bob, I get a deep satin black with 2-3 applications. The first one just kind of turns it brownish purple.
     
  20. argus

    argus Member

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    Why did you put all those lenses in a vitirine? Give them to me!!!!!!!!!!

    G
     
  21. Phil

    Phil Member

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    I found this in a book named ABC Guide to Photography - no
    date, but it looks like it was published about the time dry plates became
    popular as it mentions the 'old "wet plate" days'.

    ============================
    Brass - to Blacken

    The amateur often requires to re-blacken stops or other portions of the
    brass works of his apparatus, which have seen considerable use. The
    old black should first be cleaned off with a piece of fine emery cloth, and
    the metal should then be dipped in a mixture of equal parts of the
    following solution:-

    No. I. Solution.
    Silver nitrate..... 40 grains
    Water..... 100 minims

    No. II. Solution.
    Copper nitrate..... 40 grains
    Water..... 100 minims

    When the stops are removed from the above solution they should be
    allowed to dry, and should then be uniformly and gradually heated until they
    assume the desired black colour.
    ============================

    1 gram = 15.4323584 grains.
    Looks like a 'minims' is a drop.

    Phil
     
  22. Ole

    Ole Moderator Staff Member Moderator

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    A minim is a small volume measurement, 1/60 fluid dram, or just about a drop...

    40 grains is 2.6 gram,
    100 minims is 6.16 ml
     
  23. phfitz

    phfitz Member

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    Hi there,

    "1 gram = 15.4323584 grains.
    Looks like a 'minims' is a drop."

    60 minims = 1 dram
    8 drams = 1 fl. oz.

    I think a drop is too large. Thanks for the formula.

    One thought, if you are going to paint brass, "sweat" the moisture out of the metal first with a propane tourch and have the metal hotter than room temp. before painting but below 95*F. You will be suprised how much water will come out of the metal, it stops the paint from sticking over time.

    Good luck with it.
     
  24. Donald Qualls

    Donald Qualls Member

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    Actually, with a minim being just about 17 to the ml, a drop is just barely on the small side. A dropper tip drop of water (other liquids vary due to viscosity and surface tension differences) runs between 20 and 30 drops to the ml, though this also varies somewhat by the size of the tip the drop is falling from.

    That's a pretty stiff solution, with something over 5 grams of salts in 12+ ml of water. I'd guess the exact strength isn't critical, though, and suggest you might want to just use 3 grams of each salt in 15 ml water (divided for mixing, though it's not clear to me why you'd need to do so) and call it good. I'd also suggest you'll need to multiply the batch a bit if you need to blacken anything bigger than a Waterhouse stop.