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Author Topic: Carbon Arc (Cinema carbons Vs Gouging electrodes) Kenneth Wuepper Phenomenal Film Handler Posts: 1026 From: Saginaw, MI, USA Registered: Feb 2002 posted 11-04-2005 06:38 AM                     From the link above.."you get the optimum plate image for longer runs." These carbons are made for the printing industry and are used to image the surface of offset printing plates. The most useful light for this application is in the UV (Ultra Violet) spectrum. I have been around shops that used these as a light source and they are only burned for a few minutes at a time. KEN  |  IP: Logged Lindsay Morris Expert Film Handler Posts: 233 From: Darlington, WA, Australia Registered: Sep 2002 posted 11-04-2005 09:45 PM                     Henry, A good source of carbons for Australian consumers is Carbon Imports in Christchurch NZ. They supply the Sunny Carbon brand and when I was using carbons (2 seasons ago) I was using a mix of both Sunny and Double Eagle and there was no noticeable difference between either. If anything the Suuny's burnt a fraction longer but others on this site had found that the Sunny's they were using burnt with a yellow flame and were unstable???? I still use 6 + 7mm carbons in the slide arc and have a good screen light and for a slide arc which requires a spot some 80mm in diam to send a 3 1/4 sq glass slide up onto a 10m wide screen is pushing the boundries a bit. Contact Mark Strong on Email strongy@xtra.co.nz or phone NZ 3354 3948 or Fax 3354 3968. He posts them back and they travel well via that method... no breakages so far. If you only bring in small quantities most likely they will not get slugged GST by Customs. Mark had and I believe still has good stocks of 6mm Negs + 7mm Pos as well as 7 + 8mm ones. 12 months ago I met with him in Christchurch and he was still selling plenty as there are many small shows in NZ still running carbons. A mate of mine over here with a mobile 35mm show has just restocked his supply of 7 + 8mm carbons from Mark. Some NZ places are running 7 + 8mm setups on a 6/7 style rectifier and get very long run times out of them.. the arc might not be as stable as I would like it but it looked fine on the screen. 40amps on a 7/8 setup is a bit dodgy. Recently I visited a small (22 seater) cinema at Tinone in NSW and there he was running the entire show on carbons on one machine with a double MUTT using 7/8 carbons at about 50 amps.. light was good and arc was stable in the Westrex 14" arc lamp. Lindsay  |  IP: Logged Stephen Furley Film God Posts: 3059 From: Coulsdon, Croydon, England Registered: May 2002 posted 11-05-2005 04:18 AM                     quote: Marin Zorica It says that are high intesivity carbon arc's, so this can do well on projection, what do you think? I don't think so. Platemaking arcs are not like projection ones. The ones I've seen use much thicker carbons, maybe 12mm, though I saw a very large one once used for exposing photostencil film, and direct screen emulsions, for screen printing large posters, which used ones of about 25mm. I've not seen a platemaking arc which used coppered carbons like the ones shown in your link, I'm not sure what type of equipment these are designed to be used in. These would be too short for film projection, and I suspect that the composition of the core would also be wrong. Notice that these carbons are not specified as being 'positive' or 'negative'; in H.I. projection arcs the two carbons are quite different to each other. Carbons do not work well in the wrong polarity, even if you can get the right combination of sizes. I've got away with using a size larger carbons when the correct ones were unavailable, and under-running them, burning time was longer, but the light output not quite as good. I don't think you are going to get acceptable results which are 'incorrect' in any other way.  |  IP: Logged Jon Miller Jedi Master Film Handler Posts: 973 From: San Diego, CA, USA Registered: Sep 1999 posted 11-05-2005 09:46 AM                     On this side of the pond, Stephen, the well-known "nuArc" line of platemakers and lamps used copper-coated AC carbons. For example, this portable nuArc platemaking lamp I got for the heck of it uses a 8mm x 8" copper-coated trim (National HI Photo 88, to be precise). I think the nuArc "Flip-Top" platemaker, common in the graphic arts industry in its day as Peerless Magnarcs were in movie theatres, used the same trim, give or take a millimeter. With a static image, a DC arc was not necessary for platemakers.  |  IP: Logged Stephen Furley Film God Posts: 3059 From: Coulsdon, Croydon, England Registered: May 2002 posted 11-05-2005 11:09 AM                     Sounds like the sort of thing that the carbons in the picture are intended for. Probably more modern than the sort of platemaking arcs that I've seen. I used to do quite a bit of small offset work myself in a previous job, but that was with mercury lamps. Carbon intended for operation on a.c. are unlikely to work satisfactorily in projection lamps. Nu-Arc equipment was/is quite common here as well, but I haven't seen any using coppered carbons.  |  IP: Logged Joshua Waaland Jedi Master Film Handler Posts: 800 From: Cleveland, Ohio Registered: Dec 1999 posted 02-09-2006 07:08 AM                     I found out that the company that we got the gouging rods from is actually a projector carbon company. Their info is below. We still have some in stock but we are no longer going to carry them. ChangZheng Projector Carbon Co. Ltd. NanXun 318 National Highway HuZhou City ZheJiang Prov., China 313009 Tel: 0086-572-3912367 Fax: 0086-572-3011768 E-mail: czcarbon@yahoo.com.cn Contact: Mr. Ling Bing, General Manager  |  IP: Logged Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 02-09-2006 03:16 PM                        Maybe someone can explain this. When I was in HS, in Physics, when we were touching on electricity, it so happened that to illustrate the concept of postitive and negative electrons, they happened to show a diagram of carbon arc and a battery. However, the diagram showed the rod with the crater as being the NEGATIVE and the rod with the tip as being the POSITIVE. I was very surprised to find that it was just the opposite terminology when I got to my first booth. Why would there a totally opposite way of looking at it? Isn't positive and negative universally understood?  |  IP: Logged Will Kutler Phenomenal Film Handler Posts: 1506 From: Tucson, AZ, USA Registered: Feb 2001 posted 02-09-2006 08:46 PM                     Josh.... Some VERY nice looking beads! Are they robitic or manual and what kind of metal was being tested? Mark... EDM...correct title for EDM is Electrical Discharge Machining. EDM has many, many uses! Two types of EDM: sinker type uses electrodes, which can be a variety of materials (including carbon) and are machined to shape..then there is the wire type EDM. Anyhow, as soon as our new sinker EDM at school is set up, I want to use it for a portion of that model engine I am currently building. I want to do a small Ace of Spades brass decorative inlay, the base piece being stainless steel and the inlay being brass. I'll probably machine the electrode on our HAAS CNC VF-2, as doing it on a manual mill/rotary table would be a real time consuming pain!  |  IP: Logged Lindsay Morris Expert Film Handler Posts: 233 From: Darlington, WA, Australia Registered: Sep 2002 posted 02-10-2006 02:56 AM                     Frank, Easily explained... it is just a hangover from the days of "current flow" where the accepted direction of current was positive to negative.. hence you get a theoretical hole in the neg carbon. I grew up in the time of transisition from current flow to electron flow but even then there were many contradictions such as the left hand and right hand rules for generators and motors and then you started dealing with valves and it all went the other way. Neg to Pos. If you have a copy of Richardsons Blue Book of Projection you will see what I mean. I was always confused when I started out doing my projection training and looking at the carbons and wondering why the Pos one got the crater if the current really went Positive to Negative. But at that stage I had more valve theory under my belt than I did projection theory so I just applied the electron valve theory and I was happy until I got to the Motor and gene rules Now we all know it goes neg to pos and nobody thinks otherwise.. well not the younger ones anyway Lindsay  |  IP: Logged Joshua Waaland Jedi Master Film Handler Posts: 800 From: Cleveland, Ohio Registered: Dec 1999 posted 02-10-2006 09:07 AM                     Will, Those are actually craters in the metal that were made by the gouging rods. They appear as welds in the picture because of the way the light is hitting them. The material is mild carbon steel. We make a machine that runs on track and automates welding processes. The gouging machine is made by another company and it mounts on our carriage. It isn't as high tech as a robot but it is also 1/10th of the price of a robot and does a good job as you can see.  |  IP: Logged Tim Reed Better Projection Pays Posts: 5246 From: Northampton, PA Registered: Sep 1999 posted 02-10-2006 01:18 PM                       quote: Frank Angel to illustrate the concept of postitive and negative electrons Electrons are always negative, regardless of which theory a person ascribes to. Movement of valence electrons create positive "holes" in the conducting atom(s), which can be said to be moving in the opposite direction. That's current theory. The best way I came up with to illustrate "hole current" is to envision a theatre marquee (what else?) with lights running in a traveller fashion. The areas of lit bulbs (like flowing electrons) run in a certain direction, and are easily seen with your eyes. However, if you look at the groups of bulbs that are OFF at any given instant, between the lit ones, and you train your eye on them long enough, you will see the dark areas (holes) travelling in the opposite direction. Simple, huh?  |  IP: Logged Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 02-11-2006 08:24 AM                        Yah, I get it....thanks you guys. It's like one of those optical illusions where you look at it and you see a perfect picture....but you keep looking at it and all of a sudden a few extra cells or something in your brain snap together and you see a completely different but perfectly formed picture and the first one is just gone. It's all perspective. But actually, I am really more interested in that metaphysical moment....the precise still point of the turning world where the mind changes from one to the other and you haven't done anything at all to make it morph....it happens involuntarily. Now THAT'S the interesting thing! Some one explain THAT and I buy you a round! Hmmmm, I was up doing an all nighter.....I guess it shows?  |  IP: Logged Joseph A Sierra Film Handler Posts: 5 From: kernersville NC, USA winston/salem Registered: Feb 2006 posted 02-14-2006 01:50 PM                        change the film reader for the one that should use, the cat 702 and check the proyector speed(pulleys,belts,etc)if proyector speed is fluttering probably it will happen  |  IP: Logged

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