DIY drum rolling machine

[Dirk Rösler]

Hi, has anyone built their own Jobo drum rotating machine?

Would it be difficult to have a motor with variable speed control and adjustable reversal interval that somehow connects to the drum, by means of the magnet or some sort of "claw"?

Does not sound too difficult and perhaps parts and components can be salvaged from elsewhere. I am not an electronics person, but can do basics, soldering etc.

Regards

Dirk

[Drew Wiley]

Could easily be done, but why? There are plenty of used machines around fairly cheap, and a new DevTec for about a hundred bucks will develop prints every bit as
well as a Jobo. Things get complicated only if you want to make prints bigger than
20X24. The RPM of the Jobo is too high for some applications and the motor itself
is underpowered. You could make drums out of ABS drainage pipe and caps, but some finesse would be required constructing an efficient light trap which will still
allow you to introduce chemicals evenly. I've been down this road, and now have a
significantly modified 30X40 drum processor which will do most things well and
cost effectively, but not as conveniently as a fully automated roller-transport machine. If you like projects like this, have fun at it, but there will probably be some serious speed-bumps redesigning things which others have already spent a lot of time figuring out.

[Dirk Rösler]

Why, because I want simplicity and flexibility. And I don't have space for the bulk of the whole processor not do I need the temperature control, just something that turns the drums on a roller base. Also I want to rotate long drums that do not fit in a Jobo machine. I have the Jobo drums, so no need to re-invent those.

I have done some dev of Acros in Xtol rotating at very slow speed by hand, and the results are great, so I would like the machine to rotate at any speed I want.

For example one could salvage a hand mixer/blender/juicer, which already has speed settings and is powerful, just need to make it stepless and perhaps some gears, plus of course the reversal part.

[Drew Wiley]

Dirk - you would need a small gearmotor adaptable to a speed control, and a way
to keep all this watertight. Two parallel stainless steel shafts can be used, with the
gearbox mounted to only one of them, and the other turning on its own when the
drum rotates. A bi-directional switch is a possible option. Then you need eccentric
friction rollers on the shafts to get some random motion. This idea works quite well
for serious needs but starts getting expensive when you factor in all the parts. A far
less expensive (and less reliable) option can be copied from Dev Tec. The drum floats in a tempered waterbath. A simple friction ring is placed around the outside
circumference of the drum and rotated by a small waterproof motor with a projecting friction shaft. A simple rheostat can be used on this kind of motor for
speed control. Of course, you can simply rotate your drums by hand back and forth
on the bed of a darkroom sink too, without any fancy equipment. But an actual
Dev Tec processor takes up only about two square feet and will probably cost next
to nothing used. You might also be able to find an old motorized Unicolor roller base only.

[Dirk Rösler]

Thanks. I am using the Unicolor base already, but it is problematic with the Expert drums. For hand rolling I have castors on a wood board. No need to be watertight or anything, it should just drive the drum. Don't think I need to randomise more than what the Unicolor or castors are already doing.

I don't have access to DevTec stuff.

[IanMazursky]

Dirk,

Thats a really neat concept!
Im looking into the same thing myself for my 3063 jobo drum.
I just need to figure out how to make a motor auto reverse. Im thinking of scrapping parts from my Wing Lynch model 4 since its in pieces anyway.

Good luck!

[Nathan Potter]

Just adapt the pervasive unicolor roller base for rolling a custom drum. It'll reverse also as well as turn in one direction continuously. I've seen them for sale for a few tens of dollars.

Nate Potter, PEI, Canada

[Alan Rabe]

You might wnat to try http://www.myhurst.com/hurstmfg/index.jsp
for small high torque motors

[BradS]

I made one with my sons' legos once....but then they wanted their legos back so, I picked up a used Unicolor motor base.

[Dirk Rösler]

Thanks for the link. I was thinking of Lego too, to try...

Actually, I think I may try a cheap used electric drill. It is certainly high torque, and has speed and reverse witches built in. Just need to remove from the housing and change the control switches to some sort of knobs.