DIY Jobo Drum

[SteveH]

All,
Im trying to find a way to daylight process my 4x5 negs. I have already tried the unicolor system, and found it to be extremely good at making a mess - not so good at film development. Therefore, Im going to try a Jobo drum on my unicolor base. However, I find the prices of the Jobo items completely outragious. $259 for a plastic drum ? P.T. Barnum's skeleton must still be grinning ear to ear.
So, Im going to attempt to make my own version of the drum. My question is how does the light trap (if there is one) work on an expert drum ? Is it in the cog assembly ? If so, how does the trap work on a 2551 setup with the magnetic lid ?
At this point, I have two options. #1 would be to make 'torpedo' tubes that would fit inside of my 11x14 unicolor drum, and function similarly to the expert system. Or, I can make a new PVC housing with the tubes inside of it - this however would require the manufacture of a new light trap.
I have not been able to find some detailed photos of the expert drum's internals, but I suppose each film tube is ribbed to keep the film off of the walls of the tube ? If so, the way that I would plan on ribbing the inside of my film tubes would be to glue 5-6 beverage stirrers inside of the film tube, which should allow proper circulation. I suppose I could even slot the tubes in between these ribs to assure flow.

Thanks !

 

[claytume]

Steve

making an expert drum would not be an easy task, once you've seen one you'll understand why they cost so much.

The tubes are smooth, no ribs. Each tube is made of 2 lengthwise halves welded together. Why? Because the tubes are slightly barrel shaped to allow solution to get behind the film.

The light trap is in the lid below the cog.

The tanks look like they're hand assembled and I'd say very labour intensive, hense the price.

Clayton

 

[SteveH]

Clayton,
Ah, I see. Now I understand how it works. I've decided to scrap the idea, as it seems no matter what I do, the PVC is scratching the negs.

Thanks,

 

[Michael Kadillak]

The drums are engineering marvels and the time, materials, film and wasted time to attempt to overcome your perception that it is just a plastic drum at the end of the day will be far less costly than just paying the price of admission and getting back to making photographs.

Sometimes we are out own worst enemy. Get over it.

Cheers!

 

[Michael Kadillak]

Sometimes we are our own worst enemy.

My bad.

 

[claytume]

Clayton,
Ah, I see. Now I understand how it works. I've decided to scrap the idea, as it seems no matter what I do, the PVC is scratching the negs.

Thanks,

Steve

I too couldn't understand why they cost so much until I bought one. Then I realised they're a bargain for for work put into them and the way they work.

Clayton

 

[Jim Noel]

Not only are the Expert drums somewhat complicated to manufacture, they are also too large in diameter to work on a Unicolor base. I tried last week when the mother board on my Jobo had a problem.

 

[Buster6X6]

Hi Steve
I have used Unicolor drum for two years. You can develop two sheets in one setting.Or you can use Jobo 2521 drum for six sheets of film.Unicolor drum uses I think 180ml of solution and you need a motor base. 2521 uses1.5 l of solution and you can use it for semi or stand development.
Hope this helps. I forgot to tell you also need 2559 reel to insert your film.
Greg