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good day...
i just purchased two grafmatic backs which were supposed to be 'like new'. however, when i disassambled them to clean and lube, i noticed 3 of the 12 septums have slight bends in the notched end. they cycle fine through the device, but i am now worried about long term jamming and film flatness.
are my concerns founded... or since they exchange properly i've nothing to be worried about?
thanks, scott
Scott: Slight bends are extremely common and have not caused me problems. If you want to straighten them, you can put the blade of a knife in the slot and gently bend the corner out. Gently. My impression is that these types of bends happen when the top septum slides up and out of the box when the unit is being closed after loading in the darkroom. Being trapped where it isn't meant to be, it bends a little, or, a lot, if you force it. To avoid this, with the carriage still out, hold the septums down, slide the darkslide over the top, THEN slide the carriage back into the shell. The top septum can't slide up and over the edge of the carriage because the dark slide holds it in. It also helps to make sure that the grip on the film is tight enough (opposite end from the notched end) so that the film can't start sliding out of the septum. Good luck.
Kevin's description sounds about right to me.
Sometimes if the septum is bent near the notch, you might have to straighten it and/or open it up a bit to get the film to load properly, particularly if the film is on a thicker base. I generally load the septums by positioning the film most of the way in on one groove and bending the sheet so it pops into the opposite groove and then slide it in the rest of the way.
thanks for all the advice folks... using the flat blade on my leatherman tool and a heavy book to keep the rest of the septum flat, i was able to reshape the ones that were slightly out.
after that, a wipe down with denatured alcohol and a light lube job, these things are working like new!
thanks again, scott
Scott: Just curious -- what are you lubing them with and where are you applying it? I have some that are slicker in operation than others, but mine are all bone dry as far as I know.
Kevin
kevin: after reading this thread: http://largeformatphotography.info/lfforum/topic/497487.html
i decided to give the back a good wipe down with denatured alcohol... a toothbrush really enabled me to get into the corners and under the leaf springs. i planned on lubricating the moving parts with the elmer's slide all, but after visiting three local hardware stores and not finding it, i gave up on it. i happened to have some tri-flow teflon lube at the house (i use it on my bikes) and gave it a shot. it worked great, but didn't dry away very quickly. i had to let it sit over night. i'm now planning on ordering some of the elmers stuff of the web for periodic lubes in the future.
the cleaning and tri-flow has got these things sliding very smoothly, but as i said the lube needed some time to evaporate.
scott
Lubrication... I do not have a Grafmatic yet. However, I have reconditioned a number of sheet film holders where the dark slides were quite difficult to pull out and push in. After rubbing the slides with 000 steel wool, and cleaning with alcohol, I used Simonize paste wax. (Rub it on, and rub it off). That works quite well. I wonder if the same technique would work on the Grafmatic parts? JF