My Fix for a leaky Unicolor Drum

[Kilgallb]

I got fed up with my Unicolor Drum leaking when I develop 4x5. I had a last disaster when all the developer leaked out in 3 minutes. I found a solution. I threw out my drums and made a handy device to convert my old Paterson tank into a roller drum.

I made negative holders out of soft plastic sheet. (I cut up an old three ring binder) With properly located folds I can place 4x5 negatives in the holders and insert them into the Paterson tank. My old Multiunit-2 two tank ($17.00 from Robinson's camera in 1975 according to the price tag) can hold 4 negatives.

100ml of developer easily covers the four negatives. don't forget the center shaft, it is the light trap.

The system never leaks, ever.

Yes, you need to put the negatives in double strength hypo clear or wash aid to clear the back side. I do this in a tray. I also fix in a tray.

I have attached an image to show how it works. Probably easier to look than read my explanation.

The best thing is, new tanks are available at B&H photo for less money than an old used Unicolour drum on fleabay.

 

[koraks]

Very nice! Look out for surge marks on the sids of the film; getting the geometry of the film holder right can sometimes be a challenge. If development is perfectly even, you are golden!

 

[reddesert]

Looks neat.

For information in case anyone finds this while searching, there is a gasket under the lid of a Unicolor drum, and greasing or replacing the gasket can sometimes help stop or minimize leaks.

 

[darkroommike]

1. Haven't tried it yet but I have one Unicolor™ drum that leaks a lot, I got some spare gaskets years ago and I think new gaskets could be cut with CNC or maybe even a Cricut™.
2. I also have a leaking Film Drum but there you can just seal the lid and load the reels through the piston end.
3. Years ago I ordered spares from PSI(?), the very nice lady said I got the last batch so no more spare.
4. For sheet film processing the "best" paper drum, IMHO, is the Chromega™ 8x10 (Simmard Canada) not the Unicolor™ but I do like the Unicolor™ base since it auto-reverses. The Omega base rocks and drums without stabilizing bands walk off the base, it's nice to have both so I can compare both.
5. The Beseler Drum also works but is too narrow to fit on any motor base except the Beseler motor base.

 

[darkroommike]

Looks neat.

For information in case anyone finds this while searching, there is a gasket under the lid of a Unicolor drum, and greasing or replacing the gasket can sometimes help stop or minimize leaks.

Flipping it over can help for a while, too, since the lid then bears on a different surface.

 

[Kilgallb]

Flipping it over can help for a while, too, since the lid then bears on a different surface.

Yeah, I tried reversing the gasket,it worked for about a year. Then I went to the vaseline on the gasket. It worked for a while, but was messy. Then the big failure when all the developer leaked out.

Now, if I could get my hands on some new old stack I would jump at it.

BTW: The gasket on Unicolor spiral tank works on the roller drums. Sometime you find one on ebay. I used one for about a year.

 

[Graflex Garage]

1. Haven't tried it yet but I have one Unicolor™ drum that leaks a lot, I got some spare gaskets years ago and I think new gaskets could be cut with CNC or maybe even a Cricut™.
2. I also have a leaking Film Drum but there you can just seal the lid and load the reels through the piston end.
3. Years ago I ordered spares from PSI(?), the very nice lady said I got the last batch so no more spare.
4. For sheet film processing the "best" paper drum, IMHO, is the Chromega™ 8x10 (Simmard Canada) not the Unicolor™ but I do like the Unicolor™ base since it auto-reverses. The Omega base rocks and drums without stabilizing bands walk off the base, it's nice to have both so I can compare both.
5. The Beseler Drum also works but is too narrow to fit on any motor base except the Beseler motor base.

care to sell one...or two

 

[Donald Qualls]

I think new gaskets could be cut with CNC or maybe even a Cricut™.

This would be perfect work for a water jet cutter. Commercial machines could probably cut a stack five or six layers thick with no loss of precision from top to bottom layer. The originals were almost certainly die cut -- which is cheaper on a per-part basis for a production run, but much more expensive up front to make and debug the cutting die.

 

[Paul Howell]

What I've done is used silicon gel to seal the end with the flat odd shaped gasket, drop the reels in from the other end. A little harder to clean otherwise works, but I'm down to one, for a lack of better word, piston with functional O ring. I haven't found a replacement the right size.

 

[AgX]

Kilgallb, well done with your ring-binder sheets.
Basically the same approach Jobo did with their reducing inserts for their older drums.
The main difference is that they went for a two-element approach, where one of the arrests can slide along the main part, thus making the insert stepless adjustable for various formats. But at a DIY approach the necessary tolerance for the slider seem hard to achieve and I thus consider your solution the better one.

A problem be would films with back layers that have to be processed too. But in such cases one just would have to make the film bulge to the center of the drum instead and heighten the bath volume substantially.