Chemical storage in pop bottles.

My efforts to store my limited range of chemicals in bottles without air has lead me to use plastic bottles used for fizzy drinks.
At present I have used these easily flattened bottles for my undiluted Ilford paper developer and stock solution ID11.
A 2ltr bottle will collapse to less than 300ml so giving airless storage.
Aside from safety issues (I always remove the original drinks label and re-label with clear signs for the product within....and store in a special dark & cool cabinet) is there a reason why this shouldn't be done? I'm thinking of possible reaction between the chemicals and the plastic used. Any problem with the bottle being clear (although stored in a dark cabinet)?

Dave...

I've had ID-11 stock in such a bottle for 14 months in a cupboard and it worked fine with no apparent change in development and no discolouration of the developer over that time. I made sure it was filled to the brim before putting it away. Probably over a year is pushing it, but it worked fine. I've also had it stored the same way for assorted shorter times of several months, also without incident.

Many will recommend glass and they are undoubtedly technically correct that glass is a better material to exclude oxygen (there are indeed better plastics too), but if it works, it works...

Cheers, Bob.

Perhaps someone with more knowledge of plastics than I will contradict me, but I think pop bottle are the correct type of plastic to exclude oxygen. I would still recommend gassing on top of a developer container whether it be glass or plastic, and storing them in the dark.

Beware that beverage bottles are not as pure as one might think. In order to make PET bottles usable for beer they are now specially chemically treated inside, this is most probably beneficial for your chemistry but in principle a harmful effect cannot be excluded...

Furthermore PET is not stable against highly concentrated alkali.

I've heard all the argument for using glass bottles to store photo chemistry, and I'm still not sold. Glass is heavy and dangerous in a darkroom. Glass is slippery when wet, and has this nasty tendency to shatter into fine and very sharp little shards when dropped. Add to that the fact that you can't see so well in the dark and you have an accident waiting to happen. One day, long after you've cleaned up the broken glass mess, you'll be walking barefoot around the house and one of those nice sharp little shards that you missed will find you. It will not be pleasant.

I don't care if my chemistry doesn't theoretically last as long in plastic pop bottles as it might in glass. It lasts long enough for me to use it up without any loss of potency. It's not worth the risk of injury from broken glass. All things considered, re-using these bottles for chemical storage is a perfect solution. Do float some inert gas into the bottle as empty it to exclude air, and you'll have no problems. I use propane from a soldering torch because it is heavier than air, is cheap, and stinks so you'll know if there's a leak long before that becomes a problem.

T-Max developer works fine for my somewhat haphazard processing after months of storage in a partly filled pop bottle.

I am liable to use lots of different kinds of bottles depending on what is handy in the right size at the time I need it. Yesterday I washed out and saved a Grolsch beer bottle with a nice ceramic/rubber stopper. But I have an idea I haven't tried yet that might be either stupid or genius. I am going to get a bag of balloons .. the long skinny kind, and try inserting one down into a bottle and then blowing it up till it completely fills the bottle.
Dennis

fschifano said:

Do float some inert gas into the bottle as empty it to exclude air, and you'll have no problems. I use propane from a soldering torch because it is heavier than air, is cheap, and stinks so you'll know if there's a leak long before that becomes a problem.

Click to expand...

Are you suggesting propane is an inert gas? Sounds risky. Why not just use collapsible jugs to exclude air above the stored liquid?

The standard 2 litre coke bottles aren't as gas impermeable as they could be. They do allow a small amount of oxygen to diffuse in. Thats why drinks like lemonade will have a small amount of Vitamin C in them to act as an antioxidant to protect the lemon oils which are added for flavour. These can oxidise readily giving a musty slightly rancid flavour.

As for plastic stability PET isn't too bad, and is a good compromise. If you want something really resistant use a bottle made from HDPE.
I think HDPE is what the concertina bottles are made of but I could be way off.

Covering the solutions in a bed of propane actually makes a bit of sense as it will exclude the oxgen if you use enough. Its the same principle as industry uses when Nitrogen capping part empty barrels to keep oxygen out.
I personally would use a cigarette lighter refill to do this for convenience and the gas smells a bit better. Just don't open your bottles in front of a naked flame!

bobwysiwyg said:

Are you suggesting propane is an inert gas?

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Inert to photochemistry I guess... Isn't the protective gas from Tetenal propane or butane now since fluorochlorocarbones are prohibited.

Actually I prefer nitrogene but getting some handy installation is costly.

An easy to find replacement for combustible butane is argon. This (and a suitable regulator) can be found where they sell arc-welding equipment. I got mine from the local DIY shed. The bottles are quite large and having rounded bottoms don't stand up on their own however; I keep meaning to find a suitable clamp/holder...

Bob.

Dave,

"Aside from safety issues (I always remove the original drinks label and re-label with clear signs for the product within....and store in a special dark & cool cabinet) "

Kids don't read labels, accident waiting to happen. Hydrogen peroxide bottles are dark brown and easy to buy, work very well and don't look like soda bottles.

Just a thought.

Dave may not have kids. I don't.

dpurdy said:

I am liable to use lots of different kinds of bottles depending on what is handy in the right size at the time I need it. Yesterday I washed out and saved a Grolsch beer bottle with a nice ceramic/rubber stopper. But I have an idea I haven't tried yet that might be either stupid or genius. I am going to get a bag of balloons .. the long skinny kind, and try inserting one down into a bottle and then blowing it up till it completely fills the bottle.
Dennis

Click to expand...

Whatever turns you on! Just don't try it in public.

Thanks for the comments and suggestions.
As I said...."aside from safety issues"...., however I do take your point about kids not reading the labels on bottles, I guess that they wouldn't read the labels on the original bottles either so secure storage is mandatory.
For your peace of mind, I have no kids (under 20y) who would go near my chemicals, which are stored in the back of my garage (they can smell, she tells me!) in a lockable filing cabinet.
I have stored stock ID11 for up to 8 months with no apparent effect on it's performance and now wish to try one or two other films devs, to be stored the same way (XTOL, Rodinal).

Dave...

bobwysiwyg said:

Are you suggesting propane is an inert gas? Sounds risky. Why not just use collapsible jugs to exclude air above the stored liquid?

Click to expand...

Yes, I am and no it's not particularly dangerous. We are talking about using very small amounts of gas in an environment that should be well ventilated and free of open flames. Tetenal Protectan is noting more than canned butane, and sold for just this purpose. Why pay $12 for protectan when I can get a bottle of propane (not very different) for about $3?

Those collapsible accordion bottles are the biggest ripoff going. The caps don't seal well and the plastic is gas permeable. I have a few of them lying around. I don't use them any more.

Rujji's techno pages (now wikified, try silvergrain.org?) have a discussion of different types of recyled bottles and which chemicals they are advised for (with his knowledge to support all the field success posted here).

I believe it was #1 (PETE) for developers, and #1 or #2 (HDPE?) for the rest.

Saran (I don't know what polymer it is) was recommended as a cap liner as it is not gas permeable, or the least so.

I recall a vendo guy wheeling away unopened carbonated soft drinks from a store once & I asked it they had shelf life issues. He replied 6 weeks - they get flat enough the mfr doesn't want them on the shelves. Admittedly, pressurized is a different situation than photochem storage.

Now, this was a vendo guy; he may have had the explanation wrong - he said that the bottles DID 'breathe'. It could have been the cap too considering Ryuji's discussion of caps.

Murray