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My DIY film processor
I have been building a film processor for my darkroom to allow better temperature control than what my Unicolor motor base can provide. Taking a note from Jobo, I use their drums, but everything else is off-the-shelf parts from the hardware store or kitchen supply store.
The base is a 36x18 inch piece of melamine intended to be a bookshelf. I reinforced it with perforated angle steel and bolts to prevent sagging, then installed leveling feet. The water tank is a stainless steel buffet tray from the kitchen store with a perforated tray to provide a raised surface above the heating element.
The heater and pump are from a pet store and hold the water steady at 100°F very well. The thermostat on the heater only goes to 92°, but it had a slot in the back for an allen wrench to adjust it, so while it reads 92° on the dial, the actual temperature is 100°F. The pump is a small submersible one for lizard tanks.
The drum is supported by two stainless steel rods that rest in some of the perforations of the inner tray. The rollers are teflon rod that came with centered holes, I just cut them to length. I am still building the motor section, but it is the guts of a Unicolor base put into a new box, and I have removed one of the large wheels from the axle, then extended the axle and placed a large fender washer on the end to connect to the magnet on the base of the drum. I'll post pictures of that part once I finish it.
I built this for the challenge, and for the fact that I can easily replace any part without having to hunt down old Jobo parts. My motor may eventually give out, but I'll cross that bridge when I get there.
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Excellent beginning. Looks nice too. A couple of thoughts.
I wonder about a longer tray or a two tray setup, one for the drum and the other for chemicals. I often do a large run of multiple drums so it is nice to have a tempering bath with the chemicals ready to go.
It the temperature adjustable? Phototherm made submersible heating elements with a thermostat that work very well and would be goof for your setup, perhaps with a very small aquarium pump to circulate the water.
Do the rollers also work with Expert drums? I use a smattering of 1500, 2500, and expert drums.
Obviously, the motor is going to be the most difficult part. I don't mind manually emptying the drum and pouring in new chemicals. But the motor is the real labor and drudgery saver. It would be best I think if the motor moved a mechanism that could rotate any type of drum from BTZS tubes to Jobo Expert drums without need a special attachment point like a cog lid or a magnet. Kind of like a rotisserie basket or some mechanism that does not require the use of one brand/style of drum. I don't know how to do that but I think that a clever craftsman could develop a new, poor man's Jobo with off the shelf parts and good craftmanship that many people would buy.
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Greg - Wow! This is excellent and from the looks of it, I'd prefer it to any Jobo for the reasons you stated. Do you have any drawings, plans or part lists for this that you'd be willing to send? I'd sure like to try to tackle one like this myself.
Very nice job!
Regards,
Phil Maus
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Jerold, I only want to use this for film, so I used the largest food tray available, which will take an 11x14 Jobo drum. Since I max out at 8x10 for my film, this isn't a problem. I have used an expert drum, but like the 2500 and 2800 series drums for film. Obviously if someone were going to build one themselves, they should make it to fit their needs. As the last image shows, I can get 5-6 glass beakers with the chemicals into the water bath for tempering, and yes, the heater uses a thermostat and is adjustable. I paid $20 for it. I agree that more universal connection to the motor would allow several types of drums to be used, but since I only use one type and diameter, I designed it for the quickest and easiest type for my workflow.
Phil, no I don't have any plans, as I have made it up as I went along. But I can tell you what parts I have gotten if you need it.
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I like the idea of using a buffet-stove tray.
It seems you used cramps to fix the rods an the bushings on the rods. I have not come across SS cramps so far though.
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I like it. But what are you pumping?
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Tim, I fill the serving tray with water and use the pump to circulate it to keep the temperature steady as the heater warms it, the photos do not show water in the tank. AgX, I used these.
Last edited by Greg Davis; 09-05-2010 at 08:00 PM.
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Ah, that makes sense. I've been trying to figure how to set up a pump to cool my water bath, thought you might have my solution.
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Eager to see your pictures with the motor.
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Great idea...I had been wondering what to do when my Jobo eventually gave up the ghost.....
I'm curious to see how well the drums will drive with chemistry in them if you are not directly coupling the motor to them? Also are you going to rotate the drums in 1 direction, or have 2 way rotation like a Jobo does?
A camera is only a black box with a hole in it....
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