Using vacuum sealer for photo chems

[juan]

I have one of the machines made for vacuum sealing food in plastic bags before freezing. I was looking at my big containers of sodium thiosulfate, kodalk, and sodium sulfite I use to make TF-2 fixer. I’m thinking of mixing these chemicals in the proper amounts for mixing with 1-liter of water, sealing them and storing them that way. Anyone see a problem with that?

 

[bdial]

It seems like an idea with much merit, as long as you can keep the vacuum pump from ingesting any powder. Please let us know how it works out.

 

[MattKing]

And I guess it goes without saying - label the filled bags very clearly, and don't let them get anywhere near any bags with food in them.
I think if we had one in our household, my wife would be very uncomfortable if I used it with chemicals. I would need to buy one of my own.

 

[grat]

I don't know how effective it is for long term storage, but I did the same thing with some D76 recently, and and didn't have any problems with the powder being sucked into the sealer.

I now have a relatively oxygen free brick of D76.

 

[grat]

And I guess it goes without saying - label the filled bags very clearly, and don't let them get anywhere near any bags with food in them.
I think if we had one in our household, my wife would be very uncomfortable if I used it with chemicals. I would need to buy one of my own.

As an FYI, if you fold the top down so the top of the bag is inverted (ie, like a collar around the opening of the bag), it makes it easier to prevent any chemicals from getting on the outside of the bag. Since the sealer works on vacuum, the chances of any chemicals getting transferred into a bag containing food is roughly zero-- obviously, it's not absolutely zero, but these bags are designed for extreme temperatures, and to be puncture resistant, so some basic precautions should be sufficient.

Note, this is for dry ingredients-- for liquid, that's a whole 'nother story. Liquids can be stored in bags, but there's almost always some seepage while sealing.

I'd like some bottles with caps with one-way vacuum valves in them for storing liquids, but they're difficult to find.

 

[MattKing]

In my bachelor days, when I just had myself to reassure, I would probably have considered it!

 

[grat]

Completely understood. But the danger from raw chicken is probably greater.

 

[grain elevator]

I don't think the vacuum is that beneficial, but the airtight sealing that these machines do could be great. You could eleminate the risk to the vacuum pump by leaving it off. The small amount of oxygen in the bag probably won't do much harm.

 

[juan]

That’s exactly what I plan. Just press as much air out as I can, then use the sealer function. When I bought Kodak and Ansco fixer in bags, they were not vacuum sealed.

 

[MattKing]

That’s exactly what I plan. Just press as much air out as I can, then use the sealer function.

I could probably convince my wife to let me do that !

 

[Kino]

If you just want a sealer, get a cheap 12' impulse sealer on Ebay.

 

[wiltw]

Developer is the main thing that oxidizes...chemical reaction with oxygen, which is why folks used to spray nitrigogen into developer bottles to make it last . So I would not bother with vacuum bagging anything except developer. And just how impemeable are the vacuum bags for food?!

 

[MattKing]

The vacuum bags may also be good for keeping out moisture, and if they are fairly strong, may be resistant to physical damage, so they would be worth considering for those reasons.

 

[grat]

That’s exactly what I plan. Just press as much air out as I can, then use the sealer function.

Tip: Dunk your bag in a water bath, with the chemicals at the bottom of the bag. As you force the bag under water, the water pressure will force the air out of the bag, and if it's something like a sealable freezer bag, you can seal it with practically no air in the bag by getting the sealing strip as close to the water as possible.

Not as good as a hard vacuum, but doesn't require any special equipment other than a tub of water.

The vacuum bags may also be good for keeping out moisture, and if they are fairly strong, may be resistant to physical damage, so they would be worth considering for those reasons.

A good seal in a food storage bag will extend food life by a factor of 4, give or take. 6 months for dry products turns into 2 years, refrigerated foods go from 3 days to two weeks, frozen foods can easily hit 3 years without freezer burn, primarily due to not just the lack of oxygen, but also water vapor.

The two rolls I have right now are 4mm thick BPA free plastic. I also use them for cooking sous vide (which also means I have a pretty accurate water bath when doing developing). They're pretty tough-- you can puncture them if you try, but you're unlikely to accidentally tear them open.

Since they're rolls, I cut a length off the roll, seal it at one end, fill it, seal it at the other end. Another neat trick is to make the bag longer than needed-- then you can cut the existing seal off, remove some quantity, then reseal the bag.

 

[RichardBones]

I have a chamber vacuum sealer so I figured I would mix up the 5L Fujihunt C-41 kit and then vacuum doses of 500ML in bags. Anyone tried that and had good experience with extending the shelf life of the mixed solution?

Today I just reuse / dump back in the whole batch and works fine, but I dont develop enough to spend it before crossing the recomended shelf life, and I´m getting a little nervous.

By storing 500ml doses I figured I could save up 8 rolls and do them 4 at a time and extend the dev time for the second batch.

 

[koraks]

Anyone tried that and had good experience with extending the shelf life of the mixed solution?

I've not tried it, but it sounds like an interesting solution. One concern would be the material used for the pouches; something like PP may not work for the longer term (beyond a few weeks) due to oxygen permeability issues.

 

[Bill Burk]

I put my bags of Kodak dry chemicals into a plastic bag with cardboard support and seal with an impulse sealer.

I've had too many "punctured" bags go brown on me.

Hard enough when the good stuff is brown, how to tell it apart? If you see rat tooth marks on the bag you'll know.

 

[RichardBones]

I've not tried it, but it sounds like an interesting solution. One concern would be the material used for the pouches; something like PP may not work for the longer term (beyond a few weeks) due to oxygen permeability issues.

It´s these bags here that you can boil with, so stronger than the regular ones: https://www.sousvidetools.com/eu/va...m-boilable-chamber-vacuum-pouches-pack-of-200

It´s a mix of PE and PA. "Protected by a fully airtight polyamide (PA) outer shell” Looks promising I think but I dont know if “fully airtight” in this context is the same as no oxygen will get in over time

 

[MattKing]

It´s these bags here that you can boil with, so stronger than the regular ones: https://www.sousvidetools.com/eu/va...m-boilable-chamber-vacuum-pouches-pack-of-200

It´s a mix of PE and PA. "Protected by a fully airtight polyamide (PA) outer shell” Looks promising I think but I dont know if “fully airtight” in this context is the same as no oxygen will get in over time

Welcome to Photrio.
Those look interesting, but I do find it frustrating trying to figure out what size version you would need for any particular volume of chemical.

 

[mshchem]

Sounds like a good plan. I use glass or PET full bottles. Use enough for one or two runs then toss.

 

[wiltw]

The main problem is simply how to get the vacuum pump to stop sucking air and start to seal before it starts to suck up darkroom chemicals

 

[koraks]

It´s these bags here that you can boil with, so stronger than the regular ones: https://www.sousvidetools.com/eu/va...m-boilable-chamber-vacuum-pouches-pack-of-200

It´s a mix of PE and PA. "Protected by a fully airtight polyamide (PA) outer shell” Looks promising I think but I dont know if “fully airtight” in this context is the same as no oxygen will get in over time

They look interesting for sure. The PE lining should create a fairly good oxygen barrier. I say 'fairly good' because it's evidently thinner than the wall of a typical PE bottle, and we know those are 'safe' on a reasonably long term.
With C41 developer I find it works quite well to just monitor the color. I always mix the stuff up to working strength and then store it in appropriate containers; in my case this is mostly glass bottles. In that case, the developer appears to be stable for at least 1-2 years. On occasion I've tried to keep some developer in plastic (I think it was HDPE) containers as well. Interestingly, the color difference after a few months was very easy to spot, with the HDPE-stored developer being a shade darker than the developer stored in glass - which didn't seem to have changed at all. So you could keep a 'reference bottle' around.

 

[RichardBones]

The main problem is simply how to get the vacuum pump to stop sucking air and start to seal before it starts to suck up darkroom chemicals

That is the beauty of a chamber vacuum machine. It sucks out all the air of a chamber while the bag is in it. Seals it and then opens the valves. Looks like magic, and I dont know how it really works I´ll make a video of it if you like to see!

 

[RichardBones]

They look interesting for sure. The PE lining should create a fairly good oxygen barrier. I say 'fairly good' because it's evidently thinner than the wall of a typical PE bottle, and we know those are 'safe' on a reasonably long term.
With C41 developer I find it works quite well to just monitor the color. I always mix the stuff up to working strength and then store it in appropriate containers; in my case this is mostly glass bottles. In that case, the developer appears to be stable for at least 1-2 years. On occasion I've tried to keep some developer in plastic (I think it was HDPE) containers as well. Interestingly, the color difference after a few months was very easy to spot, with the HDPE-stored developer being a shade darker than the developer stored in glass - which didn't seem to have changed at all. So you could keep a 'reference bottle' around.

Thanks for this tip. I will make a reference bottle when I get a new batch of Fujihunt mixed up

 

[RichardBones]

Welcome to Photrio.
Those look interesting, but I do find it frustrating trying to figure out what size version you would need for any particular volume of chemical.

Thanks! Agreed. Luckily I had those bags already and they turned out to be a good fit for 500ml when I tried it with water