This is topic Silver Carbon Arc Contacts in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.


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Posted by Donald Brown (Member # 5427) on 10-14-2013, 05:40 PM:
 
Over the years, as I have salvaged numerous Strong and Ashcraft lamps, I have scrapped sets of the silver carbon contacts used in these lamps. With the variable price of silver, the cash value has fluctuated accordingly. Several weeks ago, I brought two sets of contacts in to a jeweler that I've sold to before. He brought them to an exchange in Boston, Ma. that sent them back.
While the silver was of significant value, the exchange declined to melt them down due to something in the metal that emits carcinogenic fumes.
I had never encountered this situation before.
Do any veteran arc operators or technicians know the composition of these contacts that are described in the manuals as pure silver?
Thanks,
Don Brown
 

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Posted by Jim Cassedy (Member # 4115) on 10-14-2013, 11:55 PM:
 
I ran carbon acrs for over 10 years, and this is the first time I've heard anything
like this. It's too bad they weren't more specifc than just "something carcogenic"
I was always under the impression those jaws were pure, or almost pure, silver.

Carbons were sometimes "cored" with toxic substances, but I can't see how
any of these would be transfered to the silver jaws in any amount signifcant
enough to be considered hazardous. Geez, I was breating some of that stuff for
over a decade, (even with vented lamphouses) and I'm always told I have "great
lungs" and my blood is "well oxygenated" whenever I have my big annual checkup.
So it apparantly didn't do me any harm! (yet!)

Maybe you should try another smelter?
 

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Posted by Stephen Furley (Member # 1277) on 10-15-2013, 03:13 AM:
 
Or if they're in useable condition, offer them to the few people who still use such things.
 

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Posted by Randy Stankey (Member # 64) on 10-15-2013, 11:37 AM:
 
Even when silver prices were over $30/oz., the value of the contacts as an equipment part would still have been higher than the melt value. Now that film projectors aren't used in most commercial venues and that carbon arc lamps are even more scarce, I would say that silver contacts will fast become a rarity. As such, I would say that their value, over and above the melt value is bound to go up.

We certainly don't need as many parts for projectors as we used to but, as time goes on, there is likely to be a demand for projector parts. There is likely to be an optimum number of parts to meet demand. Keeping more parts than demand necessitates is as much a waste as melting them down can be. I don't know how to predict the market for parts but I am sure that there is an optimum balance to be reached.

I say the prudent person should keep at least a couple of sets of those contacts on hand, in a case there is a need for them.

I have a Rolleiflex camera from 1955 which still works and still takes pictures as well as it did when it was new. Even though it is in "average" condition, I could sell it for $300 or more, depending on the buyer and on market conditions. Rollies in "very good" to "mint" condition can sell for $1,000 or more.

I'd say that the market for film projectors is probably going to be a lot like the market for vintage cameras. It's probably not going to be worth it to keep a lot of them around but it will be worth keeping some of them.

I wouldn't be melting the silver down, just yet.
 

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Posted by Scott Norwood (Member # 30) on 10-15-2013, 12:33 PM:
 
The part will be worthless if carbons are unavailable. Is this for 13.6mm carbons? If so, my understanding is that those have long been out of production and that the only ones remaining are NOS.

I know of one theatre that installed this year in part because carbons (8mm copper-coated positives in their case) and reflectors had become unavailable. They realized that it made no sense at this point to convert to xenon and did the sensible thing and installed DLP instead. They kept the 35mm projectors and have a stockpile of carbons, but running the equipment on a daily basis had become unsustainable.

I would love to be proven wrong on this, but the availability of consumable items will limit the potential use of this sort of equipment.
 

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Posted by Jack Theakston (Member # 4484) on 10-15-2013, 12:52 PM:
 
If they are Ashcraft 11mm, I'll buy them from you.
 

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Posted by Jim Cassedy (Member # 4115) on 10-15-2013, 08:22 PM:
 

quote: Scott Norwood

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Is this for 13.6mm carbons?
If so, my understanding is that those have long been out of production

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