JOBO CPE-2 Drum lids popping off

Mike Chalmers · Mar 10, 2019

Hi folks,

I'm having an ongoing issue, where the lid (for liquids, not the light-tight) is popping off during rotation. This happens fast and no matter how lightning fast I can jump in, I lose 1/3 to 1/2 of the chemicals into the water bath.

Sometimes this doesn't happen for several sessions then sometimes it happens twice in one session (of multiple rolls).

It usually occurs during the BLIX stage (I'm switching to a separate bleach-fix system after I run through the last of this batch) but has happened in other stages too.

I thought it might be down to over-full tanks, but I've been keeping an eye on that and I don't think that is the cause.

Would love to remove this issue from my workflow if anyone has any experience or advice?

Tank is a 1520 UniTank, but tried other tops / lids (as I have the smaller 35mm variant) with the same result.

Thanks

adelorenzo · Mar 10, 2019

Are you pushing in the top of the lid? It is designed so it will pop out to relieve the pressure.

An acid stop bath between development and blix helps a lot too. Photo Engineer has posted some threads here about why it's a good idea.

Mike Chalmers · Mar 10, 2019

adelorenzo said:
Are you pushing in the top of the lid? It is designed so it will pop out to relieve the pressure.

I'm just securing it on - are you saying I should push the middle section / button? I've never heard that before! I'm halfway through a session and will be doing another roll soon so I'm gonna try this out, thanks!

adelorenzo said:
An acid stop bath between development and blix helps a lot too. Photo Engineer has posted some threads here about why it's a good idea.

Yeah, others told me this was a good idea when I started a thread with an issue before (ultimately down to silver retention in the blix) but since then my results have been perfect and, as I'm switching systems soon, I didn't want to change my process.. Do you think it's worthwhile when you have separate bleach / fix steps?

Cheers

mshchem · Mar 10, 2019

The Red cap is designed to accommodate difference in pressure. The cap needs to be pressed in before attachment. Then if there's an increase in internal pressure the cap just pops to the normal position.

mshchem · Mar 10, 2019

Stop bath is a really good practice. Prevents a lot of potential problems .

Mike Chalmers · Mar 10, 2019

Ahhh. Yeah I pressed it in after, after reading the previous post and it caused a pop-off and developer spill..

This makes sense, will try on the next roll.

Fortunately all rolls have been successfully developed yet, in spite of this.

Mike Chalmers · Mar 10, 2019

mshchem said:
The Red cap is designed to accommodate difference in pressure. The cap needs to be pressed in before attachment. Then if there's an increase in internal pressure the cap just pops to the normal position.

Well that roll using the technique you mentioned was a success. The cap certainly felt tighter when removing each time after rotation. I'll update in 25 or so rolls and update whether this has completely solved my issue.

I've had a look at C-41 stop bath threads and it is something I'd like to pursue - is there a good resource for the best / simplest recipe and method? There was a few different ideas and want something solid to add to my workflow with the least potential issues.

Thanks again.

mfagan · Mar 10, 2019

I had this happen with a 1520 drum. Water level in bath was too high, floated end of drum enough to lever it away from the lid during rotation. Adjusted water level to be only about 3mm over drum’s lip on it’s bottom, and things were swell ever after.

Mike Chalmers · Mar 10, 2019

mfagan said:
I had this happen with a 1520 drum. Water level in bath was too high, floated end of drum enough to lever it away from the lid during rotation. Adjusted water level to be only about 3mm over drum’s lip on it’s bottom, and things were swell ever after.

Interesting, I think I automatically fill to the level you are describing anyway and don't think that's my issue (think it was the pressure button mentioned before) - but good to know about water level anyway. Cheers.

mshchem · Mar 10, 2019

Mike Chalmers said:
Well that roll using the technique you mentioned was a success. The cap certainly felt tighter when removing each time after rotation. I'll update in 25 or so rolls and update whether this has completely solved my issue.

I've had a look at C-41 stop bath threads and it is something I'd like to pursue - is there a good resource for the best / simplest recipe and method? There was a few different ideas and want something solid to add to my workflow with the least potential issues.

Thanks again.

I've been "gifted" so much Kodak Indicator Stop Bath I use it. The indicator doesn’t effect color. Otherwise I seem to recall 16mL of 28% acetic acid per liter. It's on Kodak Alaris website . Stop for RA4 is in my process as well

Mike Chalmers · Mar 10, 2019

mshchem said:
I've been "gifted" so much Kodak Indicator Stop Bath I use it. The indicator doesn’t effect color. Otherwise I seem to recall 16mL of 28% acetic acid per liter. It's on Kodak Alaris website . Stop for RA4 is in my process as well

Ah cool, I see it's available at my usual supplier for very cheap and looks like it will go a long long way at 1:63 dilution!

Mike Chalmers · Mar 10, 2019

mshchem said:
I've been "gifted" so much Kodak Indicator Stop Bath I use it. The indicator doesn’t effect color. Otherwise I seem to recall 16mL of 28% acetic acid per liter. It's on Kodak Alaris website . Stop for RA4 is in my process as well

I've been looking at the few suppliers I use here in the UK and all the stop baths seem to be for B&W.. Including the Kodak Indicator Stop Bath:

"Kodak Indicator Stop Bath is a traditional Acetic Acid general-purpose stop bath for use with B&W films and papers."

Is this the case? I can't seem to find any that mention C-41 (and if possible, RA-4 as that's my next step, starting printing next month).

Thanks

mshchem · Mar 10, 2019

Mike Chalmers said:
I've been looking at the few suppliers I use here in the UK and all the stop baths seem to be for B&W.. Including the Kodak Indicator Stop Bath:

"Kodak Indicator Stop Bath is a traditional Acetic Acid general-purpose stop bath for use with B&W films and papers."

Is this the case? I can't seem to find any that mention C-41 (and if possible, RA-4 as that's my next step, starting printing next month).

Thanks

Yes it's for black and white films and papers. It's 28% acetic acid with Bromcresol Purple indicator added. When acidic Bromcresol Purple is yellow, which appears clear under a normal OC or yellow safelight . When the bath becomes alkaline from developer carry over into the stop it turns purple, which is very apparent as a dark solution under safelights. The indicator has been a selling point for decades. Any dilute acetic acid solution will work. The Ilford stop bath is based on citric acid, does the same thing but is low odor. Diluted white vinegar will work fine as well.
You can find information on Kodak Alaris website for making non indicator stop bath from glacial acetic and 28% acetic acid. I would be VERY CAREFUL with the acetic acids, horrible odor and can burn skin and injure your eyes.
You could start with a 500mL bottle of Ilford stop and avoid the smell and strong acids.
If you can find old photo formula books there are recipes for standard stop baths.

Mike Chalmers · Mar 11, 2019

Thanks mshchem - sorry I meant I'm looking for a C-41 solution as I only work in colour in the darkroom (thus far) and this will be part of a C-41 process.

Cheers.

iandvaag · Mar 11, 2019

You can use a 1% or 2% acetic acid stop bath for C41, in fact it's recommended practice. You can just dilute pure white vinegar. Totally safe for C41 and this can definitely help with the lid popping off.

As others have said, you should definitely push in the central section of the lid. If the pressure in the tank builds up, the central section of the lid will pop out. This is your warning to take the tank off the CPE2 and "burp" the tank (relieve the pressure by taking off the lid, and putting it back on.) If you don't burp the tank after the the central section of the lid pops, the pressure can continue building and the lid can blow out even so.

This is only a problem with really fresh blix for me, after about 6 hours after mixing, I don't have this problem. I do use a stop bath though.

I also find it helps if you do 5 handheld inversions of the tank and burp the tank at the beginning of the blix step.

Mike Chalmers · Mar 11, 2019

iandvaag said:
You can use a 1% or 2% acetic acid stop bath for C41, in fact it's recommended practice. You can just dilute pure white vinegar. Totally safe for C41 and this can definitely help with the lid popping off.

Excellent, I'll do this.

iandvaag said:
As others have said, you should definitely push in the central section of the lid. If the pressure in the tank builds up, the central section of the lid will pop out. This is your warning to take the tank off the CPE2 and "burp" the tank (relieve the pressure by taking off the lid, and putting it back on.) If you don't burp the tank after the the central section of the lid pops, the pressure can continue building and the lid can blow out even so.

I've been processing today with this in mind and, honestly, it's a revelation. Feel much more confident burping and setting the lid correctly. No issues yet and I've realised that even if the lids didn't pop off previously, they would leak - and the method you describe has put an end to the leaks.

And yes - it sounds much like my experience that fresh blix causes the pop-offs more regularly.

iandvaag said:
I also find it helps if you do 5 handheld inversions of the tank and burp the tank at the beginning of the blix step.

Great, thanks! I really appreciate your invaluable advice.

Mike Chalmers · Mar 12, 2019

iandvaag said:
You can use a 1% or 2% acetic acid stop bath for C41, in fact it's recommended practice. You can just dilute pure white vinegar. Totally safe for C41 and this can definitely help with the lid popping off.

One last thing - the white vinegar readily available to me is Sarsons Distilled Vinegar - which does say contains barley / gluten. Is this suitable or should I look for more cleaning-product type vinegar?

iandvaag · Mar 12, 2019

Mike Chalmers said:
Sarsons Distilled Vinegar

What you want is a solution of acetic acid in water. Sometimes this is called "pure white" vinegar, and sometimes it is called distilled vinegar.

If it claims to be distilled, I would be very surprised if there was any gluten in it, since gluten is non-volatile. They are probably just trying to cover their bases and avoid being sued in our increasingly litigious society. The vinegar you cite "contains" barley, since it was made by fermenting alcohol from malted barley, although the alcohol was first distilled, so I'd argue it doesn't "contain" barley, rather it is made from barley.

Is the vinegar completely transparent? If so, you are probably safe.

BMbikerider · Mar 13, 2019

For as long as I remember, I have used the tops on my JOBO tank with a very small pin hole in the centre of the lid. I have an earlier type which has one in the design anyway so I thought 'Why not'? Using a thin needle I got it red hot and just melted a hole in the centre of the lid. 2 mins is all it takes and the lids are still safe against spillage because using the recommended amount of chemical, the level does not come anywhere near the centre point.

If you occasionally use the inversion method all you have to do is pop a small piece of gaffa tape over the hole or have a spare lid to hand.

Mike Chalmers · Mar 13, 2019

BMbikerider said:
For as long as I remember, I have used the tops on my JOBO tank with a very small pin hole in the centre of the lid. I have an earlier type which has one in the design anyway so I thought 'Why not'? Using a thin needle I got it red hot and just melted a hole in the centre of the lid. 2 mins is all it takes and the lids are still safe against spillage because using the recommended amount of chemical, the level does not come anywhere near the centre point.

If you occasionally use the inversion method all you have to do is pop a small piece of gaffa tape over the hole or have a spare lid to hand.

Good tip and makes sense - has this completely prevented lids popping off for you?

Mike Chalmers · Mar 13, 2019

iandvaag said:
Is the vinegar completely transparent? If so, you are probably safe.

Yeah completely transparent.. I'm confident it'd be okay, but don't wanna make mistakes..

BMbikerider · Mar 13, 2019

Mike Chalmers said:
Good tip and makes sense - has this completely prevented lids popping off for you?

Absolutely no problem whatso ever. except the time when I accidentally used a new lid without the hole. You just have to be careful.

dmb · Mar 13, 2019

BMbikerider said:
Absolutely no problem whatso ever. except the time when I accidentally used a new lid without the hole. You just have to be careful.

I wrote on the ones I acquired that someone already had put a hole in, "For Colour Rotation" - all the rest of my lids are 'virgo intacta'.

JOBO CPE-2 Drum lids popping off

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