View Full Version : Unicolor base w/Jobo Drums

Steve H
30-Dec-2005, 06:43
After reading all that I could on this site via search, I have one last question. Being as it seems the best solution (consistant/simple/cheap) for daylight processing would be using a Jobo 2500 series drum with a unicolor motorbase. The question is, what size Jobo drum do I need to fit the unicolor base ? I suppose Im looking at purchasing either the Jobo 4341 (1 reel), or the Jobo 4342 (2 reel). I would actually prefer the 1 reel version, as it would use less chems when I have a set of negs to develop differently.

Thanks yet again !

30-Dec-2005, 06:52
You need no smaller then the 2551 drum [5 reel holds 2 4x5 reels] no bigger then the 2581 drum. Holds 8 reels or 3 4x5 reels I think. Anything smaller then the 2551 won't span the wheels. Anything bigger then the 2581 drum will need to be steady by you or it'll tip over. Go for the 2551 unless you need to process alot.

Joseph O'Neil
30-Dec-2005, 06:56
The Jobo 2551 drum on a unicolor base is *exactly* the setup I have been using for several years, and it works great.

Ditto on the advice about no shorter than a 2551 drum and no longer than a 2581 drum - I know, I've tried.


Steve H
30-Dec-2005, 07:46
Great. Just the info I was looking for.

You guys are awesome.

Dan Jolicoeur
30-Dec-2005, 08:52
If you are handy at all, and scrounge around for a variable speed motor you can make your own rotary base. I used an old variable speed motor I found along with a shaft and metal flange for the magnet to hook to on a 2551 drum. I later built a water bath out of pvc stock from mcmaster. I also built a reversing timer with a relay, a simple 555 timer chip. With a couple of capacitors and resistors you can customize the rotation time to anything you want. There is a lot of information on this chip if you do a Google search on a 555 timer chip. If you like I can send you the schematic that i used. It changes rotation every 20-24 seconds. I used an old water bath heater, not really needed. I also wired in an electronic thermometer. I must tell you when it comes to electronics I am stupid. If I can do this anyone can.

Don't waste your money on an old unicolor drum that rotates less than a full turn. Build your own, and slowly add the rest of the gadgets. I'll Post some pictures on my website and directions later.

30-Dec-2005, 10:05
Dan how do you figure out how big a motor is needed? I'm tempted to build something that could handle a single reel tank but I've no idea how big a motor that would need. Figure 300ml of solution plus the weight of the tank. Any pointers?

Dan Jolicoeur
30-Dec-2005, 11:35
Nick, I used an old motor from a peristaltic pump, the kind of pump that squeezes Teflon tube, like for medical use. It is a very small electric motor. Give me a little time, and I'll email you with some suggestions. Or may be able to come up with something?

30-Dec-2005, 11:44
Dan I went and looked at my unicolor. It's rated for 110V 0.15 amps. Is it reasonable to assume a 12V 1.5 amp DC motor would be okay? The local surplus place will likely have a pile of DC motors and walwarts to provide power.

Dan Jolicoeur
30-Dec-2005, 12:53
Yes you can scrounge anywhere! I used an AC because that is what I had and the control for speed was already on it. Just keep in mind that with the unicolor you are not hanging the weight out from the end, but rather supported from the top. If i remember corectly I used a large "o"-ring as a sort of v belt to drive the metal flange. You will be much better off contolling the speed with a DC motor I think? Just experiment, and then build a water tight box for the drum and chemicals later. I think i ran mine for 2 years before I built the water bath.

30-Dec-2005, 13:17
I'm actually not worried about the water bath. The 2500 tanks on a unicolor base hold temp very well. I've managed to do both RA-4 and C-41 with the tank just sitting on the motor. I use a separate water bath to heat the chemicals but no need to float the drum it turns out.

I've posted a question to sci.electronics.basics asking for pointers on the motor controller. If it turns out to not be too difficult then this would make life easier when I only need to do one roll of film.


29-Jul-2009, 17:14
Dan, just reading an old post of yours here - do you still have any information or schematics available for the motor base/water bath you built? I'm planning to have a crack at building my own, as importing a jobo from the US is crazy expensive. Appreciate any advice or instructions you might be able to provide.