This is topic Need 8mm X 14in pos. carbons in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Bill Enos (Member # 440) on 12-20-2000, 11:25 PM:
Anybody else bought National 8 x 14 pos. recently? We received 3 weeks ago a case of Nationals that are extremely inconsistent in quality. Brightness fluctuates greatly, super bright flares, had one that would not strike! I called their customer service & was told it would be 3 months before more of this size would be made. Marble won't have any till Feb. Granted, carbon arcs are just a little antiquated but they still work quite well. Anybody got some 8 x 14s we can buy? Need enough to last till February, probably at least 150.
Posted by John Eickhof (Member # 323) on 12-20-2000, 11:30 PM:
Were thes purchased from a dealer and shipped directly from National Specialty Carbon? I
have several customers that purchase sticks
regularly and I have had no complaints on the quality of them! Make sure these have not been sitting around someone's warehouse for a long time! If they are in fact new from National, your dealer should be able to arrainge replacement! If not, next time make sure you are buying FRESH carbons!
Posted by Paul G. Thompson (Member # 655) on 12-21-2000, 01:19 AM:
Bill, I have some 8 X 14's, but they have been sitting for a while. Last time I used one out of that batch was about 4 years ago, and it perormed great, after it got done doing it's sputtering thing. A trick I learned a long time ago is to lay several carbon rods in the lamphouse while it is operating so they dry out. I noticed a remarkable improvement in arc stability. It might be worth a try, you have nothing to lose. If you are running a Peerless Magnarc, Brenkert Enarc, or an Ashcan (Ashcraft) there is plenty of room for them. 
Posted by John Pytlak (Member # 331) on 12-21-2000, 07:34 AM:
I agree with Paul. If the carbons are stored in a damp area, the moisture can cause sputtering, flares, and inconsistent operation. Dry them out, either by keeping a few on the floor of the lamphouse or in a warm (not hot) oven.Is there any chance that the package of carbons may have been dropped, cracking the carbon inside the copper sheath so you wouldn't see the damage? If you suspect damage, maybe you could pay to have a radiologist x-ray the suspect carbons, which is what Union Carbide Corporation used to do to check quality. (See issue 10 of the National Projector Carbon Bulletins in the "Manuals" section of Film-Tech).
------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Posted by Gordon Bachlund (Member # 124) on 12-21-2000, 07:44 AM:
Paul is quite correct. When I was learning the craft back in the early 1950s, my mentor taught me to keep a supply of carbons on the lamphouse floor. The heat within the lamphouse was more than adequate to drive out moisture and the carbons burned evenly and quietly.I used this "trick" through the mid 1970s and never experienced a problem.
Posted by Gordon McLeod (Member # 33) on 12-21-2000, 01:38 PM:
I think we have some still in stock at
Entertainment Equipment Corp
1800 448 1656
Posted by Bill Enos (Member # 440) on 12-22-2000, 06:50 AM:
The carbons came directly from National. There seems to be no damage, there wasn't even a dent in the box.. I keep a good supply in the lamp. National is now owned by Morgan Specialty Graphite, a British company.
Posted by John Wilson (Member # 269) on 12-22-2000, 04:00 PM:
We bought up an old theatres stock many years ago...thousands of 8's and 7's. They were very moist...goodness knows where they stored them as the boxes were fine and undamaged.I put a constant supply on the lamphouse floor and they dried out to run perfectly.
Ahhhh...the old days...(sigh)...