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Topic: Question plastic bag and humidity  (Read 1791 times)

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doom87

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Question plastic bag and humidity
« on: December 30, 2020, 06:44:07 PM »
What material is the plastic market bag made of?

 

does this material retain (hold) moisture in the bag and everything in the bag or around the bag becomes damp?

 

i put some bags inside a cardboard box and inside the cardboard box i also put dvd cases and i am worried if the bags will hold moisture inside the cardboard box and pass moisture to the discs?


doom87

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Re: Question plastic bag and humidity
« Reply #1 on: January 03, 2021, 07:55:16 PM »
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Offline billnotgatez

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Re: Question plastic bag and humidity
« Reply #2 on: January 04, 2021, 01:29:48 AM »
I only have personal experience.
I have tried to store wet clay in plastic shopping bags.
After a while the clay becomes dry.
I expect that shopping bags will block liquid water but when it evaporates the vapors migrate out.

Offline Corribus

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Re: Question plastic bag and humidity
« Reply #3 on: January 04, 2021, 10:08:02 AM »
Impossible to tell just by looking at it but most bags like that are made of LDPE, which will be practically impervious to water. The weak point will be the seal.
What men are poets who can speak of Jupiter if he were like a man, but if he is an immense spinning sphere of methane and ammonia must be silent?  - Richard P. Feynman

doom87

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Re: Question plastic bag and humidity
« Reply #4 on: January 04, 2021, 10:45:39 AM »

if i store these bags open and folded inside a cardboard box and inside the box there are also dvd cases these bags will trap the moisture that the air deposits in them and the bags and cardboard box will sweat making inside the cardboard box more humid and harm the conservation of dvd discs? the cases are next to the bags not inside them

Offline Corribus

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Re: Question plastic bag and humidity
« Reply #5 on: January 04, 2021, 11:19:07 AM »
This doesn't make a lot of sense. Air has moisture, sure, but it doesn't deposit moisture on plastic surfaces, particularly hydrophobic surfaces. If you have humid air and you enclose the humid air within a sealed plastic bag, sure the trapped air will remain humid (for a time - eventually it will pass through the plastic, but this will be slow).

Even beyond that humidity won't pose a serious problem for DVDs. They are made from polycarbonate, which isn't a water impermeable as LDPE but it also isn't going to hydrolyze or anything in damp air. At worst, leave them in a dry place for several hours and they should be fine. If you are really concerned, store them with a good desiccant.
What men are poets who can speak of Jupiter if he were like a man, but if he is an immense spinning sphere of methane and ammonia must be silent?  - Richard P. Feynman

doom87

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Re: Question plastic bag and humidity
« Reply #6 on: January 04, 2021, 05:40:23 PM »
For what reason should I trust that if I put several plastic bags inside a closed cardboard box and inside that box are also cases with DVD discs, these cases in direct contact with the bags, the person who advised me said only that plastic bag retains safe moisture so I thought that inside the cardboard box it was damp because of the bags and that person said the bag is going to sweat

doom87

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Re: Question plastic bag and humidity
« Reply #7 on: January 06, 2021, 11:32:05 AM »
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