Making paint stick!

[Dez]

I recently bought a Nikon SP which is mechanically great, but cosmetically horrible. A previous owner apparently hated black paint- every bit of it has been scraped off. The polished alloy look really does not work for a Nikon RF camera, so I want to re-paint it. I have touched up paint jobs on cameras before, but I have never been able to come up with a paint job that was as solid and abrasion-resistant as the original.

One type of paint I have available is the lovely nitrocellulose black as used on old Leicas. This is a much higher gloss than the paint used on Nikons, but it seems to have excellent adhesion, and does a beautiful job. The paint used on the Nikon F's seems to be a semi-gloss enamel, with some sort of yellow chromate primer, and that paint is pretty tough.

So I am looking for advice on surface preparation, use of primers, and the best kind of paint to use. This was a beautiful camera once. The chrome is pretty marked up, and there are plenty of dings, especially the base plate, so I have no ambition to try to make it look totally original. I'm just looking for a good, strong coat of paint.

Cheers,
Dez

 

[250swb]

I recently bought a Nikon SP which is mechanically great, but cosmetically horrible. A previous owner apparently hated black paint- every bit of it has been scraped off. The polished alloy look really does not work for a Nikon RF camera, so I want to re-paint it. I have touched up paint jobs on cameras before, but I have never been able to come up with a paint job that was as solid and abrasion-resistant as the original.

One type of paint I have available is the lovely nitrocellulose black as used on old Leicas. This is a much higher gloss than the paint used on Nikons, but it seems to have excellent adhesion, and does a beautiful job. The paint used on the Nikon F's seems to be a semi-gloss enamel, with some sort of yellow chromate primer, and that paint is pretty tough.

So I am looking for advice on surface preparation, use of primers, and the best kind of paint to use. This was a beautiful camera once. The chrome is pretty marked up, and there are plenty of dings, especially the base plate, so I have no ambition to try to make it look totally original. I'm just looking for a good, strong coat of paint.

Cheers,
Dez

Are you sure it should be a black paint camera? I only ask because I would have expected brass underneath an OEM paintjob, not chrome.

If you are painting over chrome you'll have a hard job getting the paint to stick (hence my original question), but if it is brass and just a terminology problem then I would just scuff the surface up with fine wet'n'dry and paint directly on the brass. Any auto paint shop will be able to sell you an aerosol of etching primer (ideally black) and a topcoat of satin black. The key with etching primer is to make sure you put enough on for the paint surface to be 'wet'. If you try for a delicate coat it will dry before it has had time to etch. But it should dry down to a much thinner finish than you first expect so don't worry unduly about the 'wet' coat. Use a very fine wet'n'dry paper to rub out any imperfections, then just shoot the topcoat on, again not too dry because it will dry down a lot and you want the paint wet enough to flow and self level for a smooth ripple free surface.


Steve

 

[Dez]

Slippery aluminum

Slippery aluminum

This was not originally a black camera, but all the black paint has been removed from the aluminum body casting. The person did a decent job of polishing the exposed alloy afterwards.The challenge here is that I need to paint aluminum, not brass. Paint sticks just fine to brass with reasonable preparation, but aluminum is another story. Exposed aluminum passivates in no time, and aluminum oxide is very slippery- paint simply will not stick.

I have been digging around for information- after all airplanes get painted, and alloy-bodied cameras, but the process I am finding has all sorts of downsides. The improved industrial process is something like this;
- etch the surface with highly corrosive phosphoric acid
- rinse with clear water, and dry thoroughly
- seal and prime the surface with chromic acid, which is ridiculously toxic and highly carcinogenic
- apply the paint, a two-part epoxy paint if you are really serious

😱 This does not look like a process I want to undertake in my kitchen. Today, I am going off to a store that supplies material to auto body shops, in the hopes that they have something a bit less deadly that gets used for aluminum car body panels.

This camera has a good deal of wear, and I don't have the intention to try to resore it to pristine shape. Although there are places reputed to do a great job of painting a camera they seem to be too slow and expensive for my impatient and frugal soul. What I am looking for here is a method that I can learn to do myself, with a serviceable if not perfect result.

Cheers,
Dez

 

[250swb]

😱 This does not look like a process I want to undertake in my kitchen.

No, you want to use somebody else's kitchen for that.

Have you thought of zinc chromate primer as used on airframes. I'm sure I have seen aerosols of that available. The only problem would be its green.

Steve

 

[chris7521]

If you are indeed trying to paint aluminum then it is simple. I don't really know what you have but if it is aluminum, it's easy. I have worked on aircraft for years and have done lots of painting on aluminum.
All you really need is aluminum cleaner, which is an acid. You can get it at auto parts and hardware stores. This will etch the aluminum and remove oxidation. I like to use a "Scotchbrite pad and scrub every inch of the surface and then rinse. Let dry and spray with zinc chromate primer(comes in yellow and olive green).I'd use the green since you are painting a dark color. Then you are ready to paint.
I realize you may not be looking to disassemble the camera but, if you tape things off and scrub all the nooks and cranny's with scotchbrite and a tooth brush you'll be able to rinse it off without too much trouble.
I wish brass was as easy to paint as aluminum! I can't get paint to stay on that yet! I know what I am talking about. Fear not...it's easy!!!
One last thing. Do all the prep and priming the same day since aluminum oxidize pretty quick. Then within a day or two with the paint.

 

[Ronald M]

Airframes are done with zinc chromate. After that you can paint with color.

The paints you can buy today are all soft and wear poorly. A friend uses a black spray can appliance paint that seems to hold up well and looks good.

I bought a Nikkor lens with black paint nose that was all beat up. I wet sanded it, primed and painted with Krylon black. It is holding up ok but the location sees little wear. It was aluminum under the paint. I will say the original paint is much more wear resitent than what I used. The gloss matched the rest of the lens.

After the paint dries a month or two, car wax will help preserve it.



I tried two part automobile epoxy on a Leicaflex hinge area. It did not last, but I used no primer.

The EPA has gotten after all the paint and it has all turned to trash.

You might try zinc primer, black car paint that will be VERY dull, but then use the clear coat on top. It will hold up well, but be glossy that wears down dull unless you take steps to preserve the finish.

 

[Dez]

A simple approach that looks decent

A simple approach that looks decent

The key to all these processes seems to be getting the oxide off the aluminum surface, and then quickly sealing it with something like chromate so it does not re-oxidize. I went to a local store that deals with car body shop materials and found something that seems to work.

First I went over the aluminum surface carefully with 300-grit emery paper to remove the oxide and give the surface a bit of a "tooth". This is fine enough that the paint completely fills in the scratches. Second was a prime coat with SEM self-etching primer. This is a spray, but can be brushed. It can be had in black, and provides a thin, very matte black surface. It smells horrible, so ventilation is a must.

Second was a brushed coat of semigloss POR15 rust preventative paint. This is fairly thin, and easily brushable. It dries to a gloss just a bit duller than the Nikon original.

Now I wish I could report on its longevity, but I can't. I applied this treatment to the aluminum trim of the camera back only and let it dry while I did some investigation of some mechanical faults in the body. These turned out to require parts that I could not fabricate, so I returned the camera. To get everything back to original condition, I had to remove the paint from the back after just one day, so it was not properly cured. It was VERY hard to remove, using solvents and only wooden or cork scraping tools. I think if this had fully cured, it would be very strong. I will have to have a shot at using this process on a different camera soon.

Cheers,
Dez