Norma Crud

[William Whitaker]

Both 8x10 Sinar Normas that I've seen have suffered from aluminum oxide forming on the rear standard. My current one is no exception and one of my first projects this summer will be to try to clean it up and if possible arrest its progression. The oxidation occurs most notably in the light traps where the bellows frame mounts and where moving surfaces meet (tilt and swing axes).

Does anyone have any suggestions for how to deal with this? It looks to me like it's just going to boil down to a lot of hand work with some fine wet-or-dry sandpaper after breaking down the many components. I see making some custom-fit wood sanding blocks and just digging in. I have a spray can of zinc chromate primer which I'll shoot the affected areas with prior to re-painting. I don't have any Norma-green paint, but I'm sure I can find something close.

Since this seems to be a universal affliction to Normas, I guess it'll eventually return and will have to be dealt with again.
Any thoughts on lont-term prevention?

The good news is that the camera function seems to be in no way impaired. It will be nice to have her up and running in the 8x10 mode.

[Sibben]

I had crud in the stands making rise/fall super hard on my 4x5. Took a file. White goo that could be old lube or grease. Maybe not the same thing though.

[William Whitaker]

Nope, not the same thing.

[Drew Wiley]

I certainly don't have anything like this on my Norma. Sounds like someone's been around the beach a lot and didn't routinely clean off the salt. I'd start with some
fine Scotchbrite woven pads, not sandpaper. You could also carefully test Aluminum Jelly (analogous to Naval Jelly for steel).

[William Whitaker]

Scotchbrite's a good suggestion. Thanks.

Drew, is yours an 8x10 rear standard?

[Drew Wiley]

Nope. I only have a 4x5 Norma. My 8x10 is a folder.

[William Whitaker]

I've only seen this problem on the 8x10 rear standards which are cast aluminum (I believe). Never have had the issue with the 4x5 or 5x7 components. The problem usually first appears where the rear bellows frame attaches to the standard, which is a milled surface painted black. There first appear bumps underneath the paint which is presumably oxidation beginning. Makes Norma look like she has a bad complexion. (She must not be a "Lux soap girl"...) Anyway, again and fwiw, I've only ever observed this problem on the 8x10 rear standards.

[Drew Wiley]

Might have been a mismatched primer to the paint, with something inherently corrosive to the aluminum. Once in awhile they do get things wrong over there, but
not very often.

[William Whitaker]

As I noted earlier, I've had two 8x10 Normas over the years. The first one was purchased on Ebay and had the oxidation pretty bad. The problem starts under the paint and creates "pimples" which, if opened have dusty oxidation inside. I sold that one, but regretted it and bought another in 2010. This one was from Igor Camera. I specifically asked about oxidation on the rear standard and was assured that it didn't have any.

Wrong.

Not as bad as the first one, but it had it when I received it and it seems to have grown worse in the intervening years. I've not used the camera; it's been in storage in its case the entire time. I'm pretty sure it the metal is cleaned up and properly prepared and painted that it will be fine. I hope so; I want to use it, but not at the beach.

Don't know how Jock Sturges gets away with all those beach shots he does with a Kodak Master which is metal. I've always thought any work in a salt environment was a good argument for a wood camera.

[Richard Johnson]

I had the same minor oxidation on my 8x10 Norma. I just knocked off any loose stuff and wiped it clean and didn't worry about it since the camera wasn't a mint museum piece.

[Steven Tribe]

This is endemic to all 8x10 Normas and has nothing to do with "salt air". It will have no influence on functionality the first 200 years. There is no obvious treatment, but the patchy nature of the pox and oxidation/hydration suggests it is variance in the alloy, finish or priming rather than a green paint problem.

[uhner]

My 8x10 Norma standard had oxidation in the same areas as Will describe. Most of it came off quite easily when I used an abrasive cleaning pad. I did this five years ago, and only a little bit of new oxidation has formed since then.

I’m not convinced that oxidation affects all Norma 8x10 standards though. A friend bought one around the same time as I did and his still looks like new.

I might add that I briefly owned what I believe to be an early 5x7 Norma standard that had severe oxidation in the light traps, but I have never seen it on other 5x7 or 4x5 standards.

[William Whitaker]

This is endemic to all 8x10 Normas and has nothing to do with "salt air". It will have no influence on functionality the first 200 years. There is no obvious treatment, but the patchy nature of the pox and oxidation/hydration suggests it is variance in the alloy, finish or priming rather than a green paint problem.

Thank you Steven. That's been my experience. I knew I hadn't been abusing Miss Norma.

Can anyone tell me unequivocally that the rear standard casting is, in fact, aluminum and not magnesium?

[Nathan Potter]

Will, I have no first hand experience with the Norma metal but the oxidation/corrosion problem might suggest that the metal is an alloy rather than pure aluminum. Maybe even a steel alloy containing zinc or a so called "white metal" where the alloy composition may vary from model to model. Pure aluminum has a very stabile oxide that forms quickly after polishing and reaches a stabile thickness of around 100 to 150 angstrom units over time. If cleaned properly prior to painting there should be no blistering or corrosion given that a proper primer is used.

If pure aluminum, the ultimate rugged finish would be to anodize the aluminum surface which can produce a transparent finish in the natural state or can be colored by pigmenting the natural finish. Any number of small companies can anodize parts for you.

Nate Potter, Austin TX.

[Drew Wiley]

That was slightly before the time of diecast mfg of magnesium, which I remember clearly, cause I was involved with distr for the company which first figured out how
to do that. Straight mag would have been way to weak for a part like that anyway. Mag/Al alloys have been around a lot longer. As Nathan noted, there have been all kinds of alloys, and anything Sinar would have been diecast. Anodizing is popular nowadays for cost-effective surface hardening alum, esp CNC fabricated parts, but that hardness is only a few microns thick.

[Bob Salomon]

Back in the early 60's I had three Sinar Experts in my studio. A 45, a 57 and an 810. At that time Paillard was the Sinar distributor in the USA and Norbert Kleber was the Product Manager for Sinar at Paillard.

My studio was in Darien, CT and while Darien is on Long Island Sound I never used the Sinars at the beach and my studio was well away from the water (several miles actually). That said I always had a continuing problem with the rails of these Sinars as they would develop what looked and felt like rust on the body of the rails. Even though some of the rails never were out of the studio. Norbert would make several runs from Lower Linden, NJ where Paillard was located to my studio to replace these "rusting" aluminum rails.

Never did find the answer to the problem and years later, when I sold Sinar through EPOI this particular problem never seemed to happen with the later cameras.

[William Whitaker]

Thanks for all the replies.

Found this thread (http://bbs.homeshopmachinist.net/threads/1841-How-can-I-remove-oxidation-from-aluminum?) in another forum and some of the methods suggested are specifically for aluminum and not magnesium, hence my question.

The most obnoxious aspect of this is that the lands that support the film holder are also crusty. And the last thing I want is to stick a nice clean film holder into that.

Bob, I assume by "rails", you mean the monorail sections? I haven't had any problems with that. Only the major casting of the rear standard.

It's a sweet camera and certainly worthwhile to try to find a fix, if not a cure.

[Bob Salomon]

yes, the monorail sections.

[Drew Wiley]

The main monorail sections are steel, so could hypothetically rust. But despite living on the coast, and even using my gear around beach salt spray for decades,
I've never developed any rust on these. Apparently the vintage of any gear I've owned has been properly plated. I don't know exactly how old my Norma is, but
I'm certain it isn't first generation equip. It apparently took awhile to get all the bugs out.

[William Whitaker]

My first retirement project!

[Struan Gray]

My 5x7 Norma back had this corrosion in the light trap channels. A strip of Scotchbrite wrapped over the end of a screwdriver cleaned it off nicely. I re-painted (with Airfix modelling paint, matt black) and the corrosion hasn't come back.

Aluminium in dry, clean air grows an oxide which is thin, even, hard and impermeable. With electrochemistry you can make the layer thicker, and colour it, which is what anodising does, but again, you usually get a well-behaved even layer. The thick, crusty oxides can be created by acids or alkalis, or by prolonged contact with salt water, sulphur compounds (Al foil over eggs is instructive), and all manner of more agressive chemicals.

I suspect my back had been in damp storage for a long time. The light trap channels had a black cord to provide extra light sealing, and they would have trapped moisture too. Whether the ions that damaged the Al surface were already there in the paint or primer, or whether they were in the atmosphere, is impossible to say.

There are Al-specific primers and paints if you want to re-finish your Al after cleaning off the crud, but I would reckon it is only necessary in the light traps and internal blackened surfaces. It is well worth cleaning off the crumbly flakey crud, because it will trap moisture, and it probably contains the ions which are actively breaking down the Al surface. Keep warm and dry thereafter.

Al lens barrels can end up looking equally unsightly - I have a wide angle rectilinear where the Al cells are impossible to remove from the brass barrel because this kind of corrosion has locked them in place.


PS: I don't know the 8x10 models, but the smaller format Normas have machined locating lugs to provide a reference surface which defines the rear focal plane. This is the only part I would worry about cleaning too agressively.

[William Whitaker]

Very informative, Struan. Thank you.

[Jac@stafford.net]

The problem starts under the paint and creates "pimples" which, if opened have dusty oxidation inside.

Perhaps the frame is magnesium alloy.

[William Whitaker]

Perhaps the frame is magnesium alloy.

I did ask that earlier, myself. Short of trying to ignite it, I don't know how to [nondestructively] test to determine what it is.

There have been some good suggestions. I'll post my results once I've had a chance to dive into this and will try to add some photos, too.

[Struan Gray]

Magnesium will burn in air. Good luck trying to put it out :-)

Magnesium will also react with steam to form hydrogen, aluminium does not. Again, not the best test.

Silver nitrate forms a black silver deposit in magnesium, but not on aluminium.

Spirit vinegar (24%) fizzes and reacts with magnesium, but not aluminium - which it cleans, but not with an obvious 'reaction'.

I can't help you with aluminum - never heard of the stuff.