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  #1  
Old 20th January 2020, 04:12 PM
Nat Polton Nat Polton is offline
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Default Vacuum Pump Chemical Preservation

I used to use marbles years ago to fill the air space at the top of my developer bottles. This would happily extend the shelf life of my developers.
Now that I have lost my marbles , I was wondering if the pump, vacuum kits actually work.
I first saw them being advertised to extend the useable life of opened bottles of wine.

Has anyone any experience of these pump and stopper kits?
If so do they actually work?

Cheers All.
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  #2  
Old 20th January 2020, 04:51 PM
John King John King is online now
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Default Vacuum Pump

I cannot see why they would not work. I put a post on here a couple of days ago where I related I had mixed C41developer last July and split it into smaller bottles. These bottles containing the developer (Brown Glass) were heated to around 50C and when still warm the screw caps were replaced.

The theory being as the chemical cooled the air space above became a partial vacuum. It seemed to work because I developed a film with no changes to time and printed two A4 sized pictures and the colour was as saturated as normal and there were no funny casts. How much longer it would have lasted remains an unanswered question, but a 6 month life is better than the manufacturers state.
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Old 20th January 2020, 05:03 PM
Nat Polton Nat Polton is offline
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That is a very interesting idea John. Just like bottling hot jam.
How did you arrive at the temperature to use before capping the bottles?
Its cheap and cheerful, and from what you say works.

I have not looked at my developer bottles yet, and am wondering if there is a maximum and minimum safe temperature.

I wonder if the original process lines in the factories use very warm water when mixing the ingredients for the developers. If so what is their maximum safe temperature.
I do like the sound of your method.

Cheers.
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Old 20th January 2020, 05:51 PM
Quendil Quendil is offline
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I used them for a c41 kit I had and it lasted 8 months. Only emptied the chemicals as I had put through more than the recommended amount of films.
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Old 20th January 2020, 09:08 PM
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GoodOldNorm GoodOldNorm is offline
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Yes, the vacuum pumps work very well, DaveP posted about using vacuum pumps a couple of years ago.http://www.film-and-darkroom-user.or...ad.php?t=11031
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Last edited by GoodOldNorm; 20th January 2020 at 09:15 PM.
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Old 21st January 2020, 08:04 AM
John King John King is online now
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Quote:
Originally Posted by Nat Polton View Post
That is a very interesting idea John. Just like bottling hot jam.
How did you arrive at the temperature to use before capping the bottles?
Its cheap and cheerful, and from what you say works.

I have not looked at my developer bottles yet, and am wondering if there is a maximum and minimum safe temperature.

I wonder if the original process lines in the factories use very warm water when mixing the ingredients for the developers. If so what is their maximum safe temperature.
I do like the sound of your method.

Cheers.
Pure guess work! The normal working temp is 38c so reasoning there was nothing to cook in the solutions I went up to 50-60 ish and there you have it. You will know if the vacuum has worked because when you unscrew the top there is a small inrush of air.

I have found that you MUST use glass bottles with a neoprene seal or it wont work. Cardboard ones will leak in a very short time. The developer was starting to discolour but it still worked very well so perhaps 6 months is the limit, 3-4 months will probably be safer.

Last edited by John King; 21st January 2020 at 08:08 AM.
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Old 21st January 2020, 10:49 AM
Martin Rick Martin Rick is offline
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I agree that glass bottles are best for long term storage but it occurs to me that vacuum pumps are unlikely to remove all the air. Tetenal's Protectan spray is a better, albeit costlier, solution and I would have thought that a canister of butane lighter fuel would be a suitable non-reactive substitute.
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Old 21st January 2020, 08:31 PM
John King John King is online now
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Default Butane

Using butane strikes me as being a tad dangerous. Does anyone know what the liquified gas is in cannisters such as Kenro Kenair or similar, used for dusting off film?
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Old 22nd January 2020, 06:56 AM
Martin Rick Martin Rick is offline
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Quote:
Originally Posted by John King View Post
Using butane strikes me as being a tad dangerous. Does anyone know what the liquified gas is in cannisters such as Kenro Kenair or similar, used for dusting off film?
The amount of butane in the ullage of the bottles we use would pose a minimal risk.
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Old 22nd January 2020, 10:11 AM
JOReynolds JOReynolds is offline
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Quote:
Originally Posted by John King View Post
Does anyone know what the liquified gas is in cannisters such as Kenro Kenair or similar, used for dusting off film?
Best to ask them. I remember asking a similar question of a large electronic component supplier when they described an aerosol as 'CFC-free' but then listed Freon (a CFC) as the propellant. By the way, I read yesterday that the ozone hole is growing again.
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