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DIY Jobo Expert Drum
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PostPosted: Wed Jun 02, 2010 1:05 am    Post subject: DIY Jobo Expert Drum Reply with quote

Some of you might know about the Jobo Expert Drum, which takes 5 sheets of 4x5 or 9x12 film in tubes, arranged like a revolver cylinder.



I've commenced construction of a simple imitator of that, consisting of 6 tubes inside an empty Jobo cylinder for prints. I have a longer one too, which will hold 18 films.
Photos to follow... watch this space


Last edited by Farside on Wed Jun 02, 2010 11:20 pm; edited 1 time in total


PostPosted: Wed Jun 02, 2010 1:36 am    Post subject: Reply with quote

Very curious... especially if it can save me hundreds of dollars Very Happy


What about size? Would it be usable on the lesser Jobos, like my CPE2?


PostPosted: Wed Jun 02, 2010 11:17 pm    Post subject: Reply with quote

OK, here is the Non-Expert Drum Smile

I'm fitting this to a CPP, first generation machine.
First, take an ancient Jobodrum 4531, designed to develop prints and usually to be found on ebay for a fiver or so. These drums went with the first generation of Jobo desktop machines with the magnet drive in the base of the drums. As far as I know they also fit the later machines.




First of all, a rough fitting exercise



Cut six lengths of uPVC 38mm OD waste pipe to just 2mm longer than a sheet of 4x5 lengthways, then glue them together around a shorter central tube.



Cut some 3" (75mm) lengths of uPVC reinforcing strip (this was capping from electrical conduit) and glue across every side opening.



There is an internal boss at the base of the cylinder which houses the magnet drive. To clear this, the ends of the tubes must be softened with a hot air gun and deformed with pliers, else the lid will not seal.



It needs properly cleaned up, but this is the nearly finished article.


I only have to see if it works, and even if it doesn't I realised it would be easy to glue some longer sections of those capping strips lengthways to the inside of the drum and just slide some sheet film into them. It's cheap enough to buy another drum and have one for 4x5 and one for 9x12.


PostPosted: Tue Jun 29, 2010 12:09 am    Post subject: Reply with quote

And it actually works!
Shanghai 4x5 processed in D76+3 for 15mins on Jobo CPA.
This is just a suck-it-and-see exercise - a starting point, so the neg isn't as good as I would like, but it's an image of some sort.




PostPosted: Tue Jun 29, 2010 12:15 am    Post subject: Reply with quote

very interesting, thanks!


PostPosted: Tue Jun 29, 2010 8:02 pm    Post subject: Reply with quote

It's not perfect, yet. There's a tendency for the film to stick to the back of the tubes and the anti-halation backing doesn't all remove, even with a pre-soak. I shall lightly saw shallow slots or drill a series of small holes in the position, to allow water into the back.
The remaining AH backing was just narrow streaks and easily removed whilst the film was still wet, but best to avoid too much handling, as I did scratch the negs doing it.


PostPosted: Mon Aug 26, 2013 10:23 am    Post subject: Reply with quote

perhaps a few strips of 1.5mm plastic rod glued into the tubes may work. The only contact then will be with the upper surface of the rods.

I've mocked up a photoshop version to illustrate my point. The rods perhaps need to be thinner but you get the idea. I'm sure I have seen a print tube with moulded ridges, this is just copying the idea. This also makes removing the film so much easier.



PostPosted: Mon Aug 26, 2013 8:01 pm    Post subject: Reply with quote

I'll try something like that - it's been too long since I last looked at it. The Jobo print drums have the ridges but more suited to print sizes. I thought of simply slotting film sheets in them before I did all this, but then realised there wasn't much stopping the sheets from sliding onto each other during processing. I need to look afresh at it to make sure that the introduction of ridges in the diy pipes won't reduce the internal circumference.


PostPosted: Mon Aug 26, 2013 11:03 pm    Post subject: Reply with quote

I think I may drill holes in the sides too just to get a flow going. I'm assuming the whole tank is filled not just the tubes.


PostPosted: Tue Aug 27, 2013 2:18 pm    Post subject: Reply with quote

Dave, you could try heavily scarifying the tubes' insides with 60 grit or rougher abrasive paper. I do that with my home-made film tank and process-destroyed antihalation layers are removed. Another option might be to glue some pegs to the top and bottom so that the film tacos in a way that prevents it from suctioning to the tubes. The Jobo 3010 inerst has vertical ridges inside the tube so that the film has a different arc than the tube, allowing fluid behind the back.


PostPosted: Tue Aug 27, 2013 2:35 pm    Post subject: Reply with quote

How about flexible, corrugated and perforated land drain tubing?



http://www.plasticdrainage.co.uk/underground_drainage/Land_Drainage

It's 60mm dia' and bigger, and it comes in rolls which is expensive. But I bet the DIY sheds like B&Q will have shorter rolls for domestic use.
And if you use the conduit capping or something similar to hold it all together the flex of the short lengths won't matter.


PostPosted: Tue Aug 27, 2013 11:12 pm    Post subject: Reply with quote

philslizzy wrote:
I think I may drill holes in the sides too just to get a flow going. I'm assuming the whole tank is filled not just the tubes.

I dug it out and I'd already drilled holes, but not touched it or tried it since.
Iirc, in order to lighten the load on the motor, the drum was only holding 400ml or so, perhaps less. Just enough to comfortably do the job and I suspect that I could get away with much less if the distribution is attended to.

The date on the original thread puts it just before a major health incident of my partner's and this stuff got forgotten about.


PostPosted: Tue Aug 27, 2013 11:54 pm    Post subject: Reply with quote

I have this drum too, thank you Dave!