Source for replacement 17mm nuts/washers for Barco C-series lamphouses

[Jason Raftery]

I have a site that has rounded off the 17mm hex nuts on the anode electrical connection in their C-series lamphouses. Cinionic claims to not sell replacements, except as part of the R7242451K and R724862K kits, which gets ridiculously expensive when you only need a dozen nuts. Cinionic provided the following specifications for the original part:

THREAD	METRIC
BORE(MM)	10 mm
LENGTH(MM)	5 mm
LENGTH THRD MIN	5 mm
MATERIAL	BRASS
TREATMENT	AG (SILVER)

Has anyone had success sourcing these from a supplier elsewhere or locating a substitute (e.g. nickel-plated brass, perhaps?) that's appropriate for the application?

I'd like to replace the washers at the same time if I can find them.

Thanks!

[John Eickhof]

try mc master carr supply in santa fe springs or in la area, they will have the parts you need, brass will be fine but silver plated brass is what you have, they should have the machined washers also. good luck! their fone number is 562 692-5911 location is 9630 norwalk ave

[Sam Chavez]

McMaster has the best website I know of. And they ship right quick. Amazing company!

[Jason Raftery]

McMaster-Carr is actually the first place I tried! Unfortunately, they do not sell silver-plated jam nuts.

[John Eickhof]

like i said, brass uncoated will work, but heres a link to look at Metric Hex Nuts for Vacuum Systems (uccomponents.com) john

[Mark Gulbrandsen]

When I was at CLACO I could have made them for you, and even had them silver plated. We had many DP-70 cooling plates re-silvered, and other parts anodized at Quality Plating.

[Randy Stankey]

If parts are silver plated, it's likely for good reason. Brass can stand up to heat better than pure copper but it is only about 28% as conductive as copper. Pure silver is the best conductor of electricity out of the pure metals but it can't stand up to the heat. The middle ground would be to use silver plated brass. That's my understanding of why silver plated brass would be specified for your application.

My opinion would be that, plain brass hardware could be used in an emergency to get you through until the right hardware can be obtained but I wouldn't use it for the long term.

So, sure, use the brass hardware, for now, but keep looking around for silvered brass.

If you can't find silvered hardware, I suppose you can have it plated. You could, theoretically plate the hardware, yourself, but at a pretty big expense.
You would need pure silver anodes and a fairly precise power supply. The usual chemistry for silver plating is cyanide based. Where would you find a source of silver cyanide?
I suppose I could look through my files and find a recipe for a silver plating bath but, as you can imagine, it's not a project for your average civilian. Probably better to find a local plating shop and have the job done professionally. Any decent plating shop could have the job done in a day or so, depending on their workload. The plating shop where I used to work would, often, shoehorn small jobs like this in with larger jobs.

BTW: While you are inside the machine, looking around, check all of that silvered hardware for reddish-brown stains or corrosion. It's called "Red Plague" and any silver/copper mixture that gets subjected to moisture, oxygen and heat cycling is susceptible to it. It happens when silver and copper oxidize and, the reaction is auto-catalytic. Once Red Plague starts, it spreads at an exponential rate. If you see ANY Red Plague on any silver/copper parts, get rid of EVERYTHING and replace it, ASAP. The plague starts invisibly and can contaminate an entire electrical assembly before you even know it's happening.

The shop where I work uses silver plated wire to make most of our product. Red Plague is a super-duper, big concern. Everybody who works there is trained to be on continual lookout for the plague and report it whenever found. We have, on a couple of occasions, had to scrap entire lots (tens of thousands of feet) of wire because of plague.

I'd suggest that, if you have any electrical equipment with copper/silver components, a Red Plague inspection be part of your regular preventative maintenance schedule. Since the power connections inside a projector are subject to frequent heat cycling and are likely to see some fluctuations in humidity, plague is a serious concern.

It only takes a minute to check for plague and, once you know what to look for, it's easy to spot. That extra minute's time could, very well, save you a lot of headaches in the future.

[Leo Enticknap]

BTW: While you are inside the machine, looking around, check all of that silvered hardware for reddish-brown stains or corrosion. It's called "Red Plague" and any silver/copper mixture that gets subjected to moisture, oxygen and heat cycling is susceptible to it. It happens when silver and copper oxidize and, the reaction is auto-catalytic. Once Red Plague starts, it spreads at an exponential rate. If you see ANY Red Plague on any silver/copper parts, get rid of EVERYTHING and replace it, ASAP. The plague starts invisibly and can contaminate an entire electrical assembly before you even know it's happening.

Interesting, and thanks: I've seen quite a bit of that on the nuts that Jason is looking for aftermarket replacements of: at a Barco training class we were told that these nuts were just "special, with silver in them" (or some such wording) and that they should only ever be replaced with genuine Barco ones. It's infected the threads they contact, too. Furthermore, no amount of attacking them with rubbing alcohol or DeOxit makes any progress on removing these deposits. I've contemplated getting medieval on their little asses and resorting to acetone, but decided against it, fearing that this might risk damaging the silver component, or just the alloy in general.

For some reason, this problem is nothing like as bad on the larger (21mm or 22: can't remember) equivalent nuts in the B series lamphouses.

[Mark Gulbrandsen]

Home made silver polish works (1/2 cup white vinnegar, and 2 TSP baking soda in 1/2 cup very warm water usually takes the (black) silver sulfide off... give it 2 to 4 hours... In leiu of that try toothpaste and a toothbrush.

[Randy Stankey]

Yup! That's plague!

It's, basically, a form of galvanic corrosion that converts copper to cuprous oxide. (An electron potential difference between copper and silver that drives the reaction.) It often begins in places where the silver coating is disturbed or damaged, leaving an exposed copper-silver interface. The presence of moisture, oxygen and heat serve to accelerate the conversion of copper to copper oxide.

If not addressed, it can lead to total circuit failure.

I suppose, if you are talking about larger conductors like the power connections on a xenon lamp, it isn't such a grave concern but, if you are talking about small, electronics circuits, it can quickly destroy the device.

Are any of the wiring harnesses or connectors made of silver plated copper? If you strip a wire back and clip off the end, do you see silver on the outside surface and copper in the center of the wire? Is there silver solder on copper? Any silver/copper interface is susceptible to plague.

The worst part of the problem is that the Cu > Cu2O reaction can self-catalyze. Once it starts, it increases exponentially.

Where I work, the only solution to plague is to scrap any affected parts and replace. If you consider that some of the copper that used to conduct electricity has been changed into less-conductive copper oxide, when you are working on high performance electronics, that's a bad thing.

I suppose, you could try a dilute solution of hydrochloric acid to remove the corrosion but at what risk? If you drip HCl on other sensitive parts of the projector, you could accidentally scrap the whole machine. Don't forget that you aren't really solving the problem. You are only removing some of the copper that used to conduct electricity. Further, once that copper is removed, you have only created a new site for the formation of plague.

Since plague develops, first, in places where a silver coating is damaged, I would expect it to form in the recesses between screw threads. That's where all the force is concentrated. Right? Because larger hardware bears more force, I would expect greater potential for plague.

I don't know what else to say that wouldn't venture further off into the realm of conjecture than I already have. You could check out the Wikipedia article: https://en.wikipedia.org/wiki/Red_plague_(corrosion)
There are some good links at the bottom, in the reference section of that article that lead to some documents from NASA and ASTM/ESA that discuss Red Plague.

With all that, said, the best solution to plague is to scrap and replace any affected parts.

Home made silver polish works (1/2 cup white vinnegar, and 2 TSP baking soda in 1/2 cup very warm water

All you are doing is converting acetic acid and sodium bicarbonate into sodium acetate and releasing carbon dioxide gas in the process. It looks like it's doing something because it fizzes up but, in reality, doesn't do much. It's the liberal application of elbow grease that's doing most of the work. Probably better to use just white vinegar if you want an acid cleaner or, if you want an alkaline cleaner, straight bi-carb. HCl is the prescribed substance to remove plague but, when you do that, you only create a new place for plague to form, again.

Again... When it comes to plague... Scrap and replace.

[Marcel Birgelen]

It's, basically, a form of galvanic corrosion that converts copper to cuprous oxide. (An electron potential difference between copper and silver that drives the reaction.) It often begins in places where the silver coating is disturbed or damaged, leaving an exposed copper-silver interface. The presence of moisture, oxygen and heat serve to accelerate the conversion of copper to copper oxide.

It's interesting to see how the presence of moisture apparently causes a sufficient potential differential to get a galvanic reaction starting. I've seen similar things in water mains where couplings of different metals meet, and where the flow of water apparently causes some form of electrical potential that then causes one of those couplings to oxidize in "fast forward" mode, up until one of them fails completely.

[Paul H. Rayton]

Around here (Southern California), that kind of "reaction" can be experienced in homes, as well, albeit on a smaller scale. Many homes in this area put up before about 1960 were often built using galvanized cast iron piping for all the interior plumbing. Over the years, sediments would build up in the cast iron pipe, resulting in gradually-worsening water pressure. After 50 years or so, it was time to re-plumb the house. By the 1970s, the price of copper had come down, so it became popular to replace the iron piping with new copper pipe. But if any original sections were to be retained of the iron piping (for some reason, such as to retain old fixtures), a special dielectric union, or fitting, needed to be utilized between the copper and the iron, to avoid the electrolysis and accelerated corrosion ... and potentially a leak later on at some very inconvenient spot under the home or in the wall. During our years in SoCal, we've re-plumbed two such homes, and learned early on (and in advance, not "the hard way") about the need. Nowadays, home piping in this area is most often some variant of plastic, like PVC or PEX.

[Steve Guttag]

Interesting, and thanks: I've seen quite a bit of that on the nuts that Jason is looking for aftermarket replacements of: at a Barco training class we were told that these nuts were just "special, with silver in them" (or some such wording) and that they should only ever be replaced with genuine Barco ones. It's infected the threads they contact, too. Furthermore, no amount of attacking them with rubbing alcohol or DeOxit makes any progress on removing these deposits. I've contemplated getting medieval on their little asses and resorting to acetone, but decided against it, fearing that this might risk damaging the silver component, or just the alloy in general.

For some reason, this problem is nothing like as bad on the larger (21mm or 22: can't remember) equivalent nuts in the B series lamphouses.

Leo, try Tarn-X first. See if that works.

By far, the biggest problem I've seen on the Barco electrical failure (presuming people are tightening things to spec, first) is the "Nut" that Barco uses to mate with the lamp adapter. There is a nut attaching the cable to that that is suppose to be torqued to 17 Nm but nobody ever checks it because it is hidden. Compounded is that Barco chose to use a star washer instead of something like a split washer or, better, a wave washer. That junction is going to thermal cycle and once it does it enough such that the star washer isn't doing anything anymore, it will just fail. At least a wave washer or even a split washer will keep tension on the threads through the thermal cycles.

[Mark Gulbrandsen]

Yes, a pretty strange design, overall. And they really should have known better by the time this projector hit the street. None the less, the Silver Sulfide can still be removed and the hardware polished. But doing so would have to become part of the lamp change. The same thing happens with the huge contactors used in electrical distribution. Those contacts, which are mainly in the contactors located in substation control panels get regularly maintained and when the contacts are out of spec, they get replaced.

[John Eickhof]

the really sad part is why cineonics would only offer the parts in a kit...they have to source the part individually so how difficult is it to cost out a single part since they probably have hundreds of the one part in a bin at the assembly plant...i guess customer service takes second fiddle to profit...too bad...at least with film equipment you could buy any single part you needed! Charlie Wolk once told me " it doesn't matter if the part is 25 cents or 25 dollars, I will still make a living!"