View Full Version : Sources of tubing for 8x10 BTZS-type developing tubes
Donald R. Cassling
After constructing 4x5 film developing tubes based on the instructions in Phil D avis' "Beyond the Zone System," I was going to build some tubes for 8x10 negativ es, which require 3" diameter ABS or gray Schedule 40 PVC tubes. My only proble m has been that I've hit a brick wall in trying to find that kind of tubing in t he Chicago area. Apparently, ABS is not used very much anymore, and everyone in this area seems to use white PVC pipe, which is unsuitable for the film tubes. Does anyone have any suggestions on where I could track down appropriate tubing in the Chicago area or through mail order? Thanks very much.
Having not read the book I am at a loss as to why the white PVC is unsuitable, but try the electrical supply houses for the grey PVC which is used as electrical conduit. Failing that drop an e-mail to me and I will look up the ABS out here. There is tons of it at Home Depot (do they have them in Chicago area?)
Sean Billy Bob Boy yates
Could you paint the exterior of the white PVC black?
Donald R. Cassling
Thanks very much for the quick responses. Donald, the white PVC won't work, because it's translucent, and would fog the negative. There are lots of Home Depots and similar stores in the Chicago area, but the only ABS tubing they carry is 1 1/2" in diameter. I've seen the grey PVC pipe for electrical conduit, but only up to a 2" diameter size. I'm going to try out Sean's suggestion of painting the exterior black, but, if that doesn't work, I may take you up on your kind offer to see what sizes of ABS tubing are available where you live.
Sean, after posting my original message, it also occurred to me that painting the outside with a black enamel paint might do the trick. My only concern was whether an oil-based paint it would react with the stop bath or the fixer. A contractor I talked to said that, once dry, enamel paint reacts with almost nothing. Perhaps a marine enamel would be safest. I'll try it out and see what happens, but if anyone out there already knows the answer to whether oil-based paints will react with fixer or stop bath, I'd appreciate hearing from you. Thanks again.
I have had much good experience using the rubberized material that is used to insulate tool handles. I use the black version of this for it's light-tight qualities, cut it 1:2 with thinner as described on the can, and paint it on a roughed-up surface. This makes a rubberized, easily-gripped, resilient, light-tight, and pretty tough surface on most things, and seems to me to be chemically inert. I use it mostly on hame-made cameras and lens adapters, but have used it in the darkroom for home-designed aids. But I bought the BZST tubes from Fred Newman in AZ because you get a water-tight, gray tube with o-rings and threaded top (that is also a perfect measuring cup for the chemistry). I have 4x5, 8x10, 7x17, and 12x20 and they are beautiful.
I am just getting into 8x10 and having a problem with getting even developement on my negatives. I'm using an 11x14 tray, one sheet at a time. you can see the uneven developement in the sky area. I guess this is from poor agitation. I heard of tubes. How about the tubes used for color paper developement. I also have a motor base. I wonder about the speed of rotation? Could wire in a dimmer switch to control speed, I guess. Might try this. Dave
Sounds like a job for duct tape!
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