Ferrous Tins inside Mylar - A Quick Recipe For Disaster?

[EchoPlex]

After reading numerous recent examples of tin corrosion from tin collectors and smokers on Instagram, seeing the question raised on Reddit, and seeing that @beezer 's informative thread from 2021 is closed for further comment, I believe this is something that really needs to be investigated and discussed further. @Groot5225 also posed a question specific to SG tins here, but I think this really needs a dedicated thread on the subject of Mylar itself (or maybe beezer's old thread can be reopened?). Using Mylar to preserve tins for deep storage seems to be gaining in popularity and it might just be the worst thing we can do.

It appears that some ferrous tins are rapidly corroding inside of Mylar bags due to some sort of electrolytic or galvanic corrosion (i.e. a reaction between the iron in the tin, the gases inside the bag, and the aluminum inside the mylar). From limited anecdotes online, it seems as though some ferrous tins can begin corroding on the coutside surfaces in less than a year under these circumstances. If you have Instagram, check out npod101 's post from June 3. (@npod is this you? Would love for you to chime in and share your info!) It is quite saddening - Tin after tin with severe outer corrosion...

Would love to continue a discussion on this subject and seek further examples from members. Can some of you check your older bags? I Mylared a bunch of mine 2 months ago and just took them all out as a precaution. No corrosion, though I did use O2 absorbers.

 

[AppalachianPipe92]

His post made me rethink some of my storage methods. Hate that it happened, but very glad he shared with us what he found.

 

[hawky454]

This has concerned me too, but I don’t know if it’s enough to go through all of my cellar to take the tins out of mylar. I’ve had SG tins develop bumps on the outside if the tin, I assumed this was rust build up due to the moisture slowly leaking from the tins. I haven’t noticed anything within a years time but around the 5 year mark. I still think they will last decades before it becomes a problem and I’d rather deal with this problem than the tobacco inside the tins drying out to mummy dust. We just have to weigh the risks and try to mitigate them as much as we can. I very much expect to have some loss down the road.

 

[sablebrush52]

I don't Mylar tins. I transfer the contents of tins to Mylar or jars. So far no issues. I have bought a number of tins that were in Mylar from people selling off parts of their cellars, some of which I've had for years. So far no issues with any of those that I opened.

 

[FurCoat]

Put the tin in a zip-loc sandwich bag before placing in mylar.

 

[oldgeezersmoker]

If there is a problem, wouldn't O2 absorbers help? Or silica gel? Both?

ETA: or @FurCoat 's suggestion?

 

[EchoPlex]

Put the tin in a zip-loc sandwich bag before placing in mylar.

Great and simple suggestion if corrosion only occurs upon physical contact of the two metals. One of the principle questions that needs to be answered.

If there is a problem, wouldn't O2 absorbers help? Or silica gel? Both?

ETA: or @FurCoat 's suggestion?

A definite no on dessicants, since gasket-sealed tins breathe, to some extent, you'd run the risk of drying the tobacco. The jury is still out on O2 absorbers. Some more examples from forum members would be great for data.

 

[verporchting]

This is a bit of a concern because I have hundreds of tins in vacuum sealed bags but so far I haven’t seen any indication of rust and the oldest tins are 2014-15. I will keep an eye on them but hopefully it doesn’t develop into a problem. I can say the moisture level has been perfect when I have opened the tins after 8-9 years.

 

[sablebrush52]

Was the metallized Mylar used for these failed storage attempts food storage grade? Not all Mylar products are the same. Any photos? When I posted about the tin failures and corrosion issues with the C&D tinning of early Pease blends, I provided the evidence.

But more importantly, maybe this is a sign from a higher power that your puny, perverse and unnatural attempts to preserve your pathetic stocks are doomed to fail precisely because they are puny, perverse and unnatural.
Tins were never meant to provide years of integrity on the shelf. This whole faith in the necessity of aging may be puny, perverse, and unnatural.

For those of you scheming to gouge a future market, the preservation of the tin is paramount. It must look, on the surface, factory fresh, with the promise of the contents, which are not guaranteed, to be equally fine. It's a great racket. All that's guaranteed is an unopened tin. The contents are what they are. And people fall for this constantly. Where else can you get away with crap like this? So maybe this is a higher power's gentle suggestion that you get off the grift.

If all you're aiming to do is to preserve tobaccos for your own use, the original packaging is superfluous. Jar or bag the contents, provided you haven't introduced mold or other contaminants while transferring contents, you should be fine. If you're a lazy slob, that's your problem.

We know that tobaccos store and age just fine in Mylar, as well as jars. So stop with the belt and suspenders approach to trying to screw the market. The universe is not supportive.

 

[ThermionicScott]

If you trap moisture in the Mylar with the tins, it makes sense that they would eventually rust. It seems that waiting for really dry conditions would be a good idea before sealing tins in Mylar. Silica packets sound like a good idea at first, but then if the tin loses integrity inside the Mylar, now you have something that will actively try to suck up moisture from the tobacco!

I've read that trying to vacuum-seal square tins inside a bag or other container can have the unintended consequence of popping them, since the pressure differential is what normally helps hold them closed.

I've also heard of wrapping the tins with heavy-duty foil tape to help hold the tins closed and provide a backup seal. I think that would be my preference, because then you can visually inspect the tins on occasion. Concavity is my first check for how well a tin's vacuum seal is holding...

 

[mingc]

First, I believe that the aluminum layer is overlaid by another non-conductive plastic layer so it doesn't contact the content. So, there can't be any galvanic reaction between the tin and the aluminum.

Second, tins leak odor and moisture, albeit slowly. I think that the corrosion, if any, is due to moisture coming from inside the tin.

Third, the npod101 instagram post mentioned by OP: Login • Instagram - https://www.instagram.com/p/CtCpQXGuSx8/?utm_source=ig_web_copy_link&igshid=MzRlODBiNWFlZA==

 

[sablebrush52]

I think that the corrosion, if any, is due to moisture coming from inside the tin.

That would certainly be consistent with all of the damage I photographed and shared with the C&D tinnings of Pease blends:

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With all of the crazy "collectible" tin buying action on eBay I've been following a lot of auctions. Several have caught my eye because they are offering something a bit different. Here's one that just completed...

pipesmagazine.com

 

[EchoPlex]

Was the metallized Mylar used for these failed storage attempts food storage grade? Not all Mylar products are the same. Any photos? When I posted about the tin failures and corrosion issues with the C&D tinning of early Pease blends, I provided the evidence.

But more importantly, maybe this is a sign from a higher power that your puny, perverse and unnatural attempts to preserve your pathetic stocks are doomed to fail precisely because they are puny, perverse and unnatural.
Tins were never meant to provide years of integrity on the shelf. This whole faith in the necessity of aging may be puny, perverse, and unnatural.

For those of you scheming to gouge a future market, the preservation of the tin is paramount. It must look, on the surface, factory fresh, with the promise of the contents, which are not guaranteed, to be equally fine. It's a great racket. All that's guaranteed is an unopened tin. The contents are what they are. And people fall for this constantly. Where else can you get away with crap like this? So maybe this is a higher power's gentle suggestion that you get off the grift.

If all you're aiming to do is to preserve tobaccos for your own use, the original packaging is superfluous. Jar or bag the contents, provided you haven't introduced mold or other contaminants while transferring contents, you should be fine. If you're a lazy slob, that's your problem.

We know that tobaccos store and age just fine in Mylar, as well as jars. So stop with the belt and suspenders approach to trying to screw the market. The universe is not supportive.

I don't know what type of Mylar bags were used, hence this discussion and request for examples via this thread. Videos can be found on npod101 's June 3 IG feed here. More data is certainly needed.

Tongue in cheek, I'm sure, but you forgot a paragraph about people that simply like to preserve the joy and excitement of opening a very old tin, whether it be for themselves, their kids, or the future pool of pipe enthusiasts. I think the universe supports the idea of doing stuff that makes people happy.

There should also be a section on the people that prefer provenance, or procuring a precious, peerless, and/or priceless tobacco from the source vs. Pastor Paul's ziplock baggy "cellar".

 

[EchoPlex]

First, I believe that the aluminum layer is overlaid by another non-conductive plastic layer so it doesn't contact the content. So, there can't be any galvanic reaction between the tin and the aluminum.

Second, tins leak odor and moisture, albeit slowly. I think that the corrosion, if any, is due to moisture coming from inside the tin.

See, this makes the most sense to me. My bags are 7 mil pleasant hill food grade and there is zero contact with aluminum. Maybe a simple reaction with the off-gassing of corrosive gas from the tobacco inside the tin. Interestingly, many of my own mylar bags had swelled with some gas over a period of only 2 months. This suggests to me an extremely humid environment of potentially corrosive gas.

 

[sablebrush52]

The simple solution for all of this is to simply stop selling tins. In a recent thread on G&H deliveries, much of the difficulties could be traced back to tinning. Dump tinning, just sell in bulk. People can then decide how they want to deal with their personal preferences toward the handling of their purchase. Cuts costs, saves time, less pollution and freedon for all. Tinning is clearly the devils hand job.

 

[mingc]

See, this makes the most sense to me. My bags are 7 mil pleasant hill food grade and there is zero contact with aluminum. Maybe a simple reaction with the off-gassing of corrosive gas from the tobacco inside the tin. Interestingly, many of my own mylar bags had swelled with some gas over a period of only 2 months. This suggests to me an extremely humid environment of potentially corrosive gas.

Right. The corrosive gas is water vapor, which causes iron (which is what tins are made of) to rust.

 

[sablebrush52]

Interestingly, many of my own mylar bags had swelled with some gas over a period of only 2 months. This suggests to me an extremely humid environment of potentially corrosive gas.

Very interesting. Until I prepped for the move by decanting the tobaccos from jars (heavy and breakable) to Mylar (light and tough) I mostly used jars for storage. The Mylar storage I have done, around 70 bags, hasn't shown any of that sort of bulging, and some of it is 5 to 6 years old. I often lower the humidity of a blend before committing to storage in an attempt to discourage activating any mold spores in it, because there are always mold spores in the tobacco we buy.

 

[sablebrush52]

I don't know what type of Mylar bags were used, hence this discussion and request for examples via this thread. Videos can be found on npod101 's June 3 IG feed here. More data is certainly needed.

The bagged Pelican tins shown in the video are not in metallized Mylar, so no aluminum involved. Mylar by itself isn't impermeable, gas exchange does happen. That's why Mylar is aluminum coated for long term storage. It's the coating that make the Mylar impermeable. So mylaring in clear Mylar is next to useless, as the Mylar will pass oxygen, water, etc and the contents will eventually dry out.

 

[EchoPlex]

The bagged Pelican tins shown in the video are not in metallized Mylar, so no aluminum involved. Mylar by itself isn't impermeable, gas exchange does happen. That's why Mylar is aluminum coated for long term storage. It's the coating that make the Mylar impermeable. So mylaring in clear Mylar is next to useless, as the Mylar will pass oxygen, water, etc and the contents will eventually dry out.

Right - he was showing that those bags had no corrosion, but there's 6 other videos to swipe through showing the metalized ones and his realization that all the metalized ones were corroded, while the non metallized were not.

 

[Wet Dottle]

I see many overthinking storage. My tins are stored in containers that are hermetically closed and with one of these (or similar) inside:



I have 30 year old tins without signs of rust that lived in Mississippi for years before being transported to Colorado, and are still going strong. Actually, I never had rust problems from the outside of the tins (on the inside is another matter).