JOBO style drum inversion question

[atlcruiser]

Hi all,
I have the 1510 and 1530 (i think) which can be coupled together to hold more reels of 120/35. In rodinal or E6 where temp is an issue i use my meth lab cooker to keep things cold or hot as required.

With the 1510 tank and 2 rolls of 35 or 1 roll of 120 there is not an issue; i sit it on the bottom then,when inverting, just flip it over. It is about 70% immesed in the cold/hot water

If i use the larger tank then only about 1/3 of the tank is in the water bath. I have expermented with water temps and I can get a consistent temp by increasing/decreasing the bath temps. This way I can use the tank upright then flip it as needed. I am not happy with the system.

Here is the question: What happens if i follow normal inversion but lay the tank on its side in the water bath in the same attitude as if it were on rollers? i would mark up/down on the tank so each normal inversion would also be laid back into the water bath inverted as well. This way I would have about 50 to 70% of the tank in the waterbath at all times and keep a better temp.

 

[Never Satisfied]

Hi David, I think your tanks are designed for the Jobo machine, which rotates then in a temperate bath and is heated by the Jobo machine.

The tanks are designed for rotary use and not for inversion.

You may need to swap to a Patterson system?

Andrew.

 

[tlitody]

yes you can do that but you must either have tank completely full of chemical or keep the tank rotating with changes of direction so as to randomise the flow of chemicals over the film. With the latter option you can use much less chemistry and since it will be constant agitation your dev times will be reduced by approx 15%.
Or just buy a cpe2 processor which will do the rotation for you and keep the tank level so that chemistry is not at one end or the other. You would need magnets for base of tank if you haven't already got them.

 

[atlcruiser]

I might pop for the CPE2 but i have a pretty good process right now with great results...the issue is that the results take too much time unless i cna use the big tank!

I considered getting/making a roller base and making the rest of the odds and ends...

Anyone know the rpms of the jobo rotary processors?

Normally I use about 85% of the JOBO suggessted "full" chemical amounts for hand inversion; i might bump that up a bit.

 

[sevo]

Here is the question: What happens if i follow normal inversion but lay the tank on its side in the water bath in the same attitude as if it were on rollers?

The tank can only be filled to 80% or so, as there is air space in the lid, and you even need some more airspace to get efficient agitation by inversion. This will leave something like the top third of the film in air, creating very irregular development as the film near the spindle always receives 100% development while the outer zones only get somewhat less than 50%, and even that only if you agitate perfectly and continuously - otherwise it will be a mixed bag of 0-100% across the length.

At the very least, you would have to reduce the amount of chemistry to the level recommended for rotation. To get good results, you will have to replicate the action of a processor by spinning the tank back and forward for three rotations each at one rotation per second, floating in a basin of warm water - I've done so in a pinch when my processor broke down.

Sevo

 

[tlitody]

I might pop for the CPE2 but i have a pretty good process right now with great results...the issue is that the results take too much time unless i cna use the big tank!

I considered getting/making a roller base and making the rest of the odds and ends...

Anyone know the rpms of the jobo rotary processors?

Normally I use about 85% of the JOBO suggessted "full" chemical amounts for hand inversion; i might bump that up a bit.

Jobo made a little hand roller base. I have one. BUT it only works well with bigger tanks. My 2521 which takes two reels is barely long enough to fit on the rollers. The longer 2551 would be better but takes more chemistry.
That would be fine for B+W at around 20degC. But not much good for E6 where you need 38deg C I think. You would need the tank in a water bath to keep temperature up. Hence the CPE2 or up would be your best option for E6 unless you are thinking of putting the roller base in the water bath.
I think the 1510 would be too short with the jobo roller base. With the extension it may be long enough but I'm not sure if the 1500 tanks are really big enough for the jobo roller base.

 

[atlcruiser]

Here is the thread on the meth lab:
http://www.rangefinderforum.com/forums/showthread.php?t=94945&highlight=meth

Using the small tanks I spend way too much time per roll....i thought of using 2 small tnaks at once and staggerign my start times a bit but that will very soon get complicated.

A long tank will work upright but it is difficult to really get the temps correct over the increased volume of chemical. It works much better for the rodinal at 18' as i can get it to "sit" at 18' with little issue. The increased amount of time with the rodinal seems to give some more room to temp changes.

With E6/C41 It is more difficult to stay in the correct temps. My initial thought...which was more or less correct...was that inverting every 30 seconds will prevent the chemicals from cooling too much between inversions. I did a dry run and the temps were good overall inside the tank but it is difficult to ensure that the volume of chemcal is all at the correct tepm.

As long a the tank is inverted and the chemicals move evenloy across the film I think i will be ok.