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Can I Just... Open A 30% Peroxide Bottle And Close It Back To Later Usage Without Any Explosions?

Discussion in 'Skulls and Skeletons' started by belizab, Apr 13, 2021.

  1. belizab

    belizab New Member

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    Hello!

    Sooo.... I have a few skulls to whiten, sanitize. I always used H2O2 30%.
    First time i had a bottle which had a very tiny hole to squeeze out the liquid.
    Next time i only could buy it in a bottle with big opening like the normal bottles, so it definitely gets contact with oxygene when opened. I wanted to use half of the peroxide and leave the rest in the bottle but after i closed the bottle back the bottle begun to heat up and i was afraid of it exploding so i had to use up all the peroxide.

    Now i bought online a 5 litre (1.3 gallon) h2o2 which i thought will have a bottle with tiny hole, but nope. It has a big opening and now i am not sure if i can just por out a little and close the bottle, leaving the rest for later use.
    Not sure if it is safe to close the bottle after opening it.
    Or should i delute it with water and store it that way.
    If so, i wonder how much water should i add to 5 litre/1.3 gallon h2o2 to dilute it so i can store it safely.

    Its basically impossible to find smaller volume H2O2 in big quantities in my country so i really can't go to the shop and pick the best one i see so i had to risk it ordering online.

    Either way thank you so so much!
     
  2. joeym

    joeym Old Murphey

    Just screw the lid back on the container. 30% peroxide is not going to explode due to atmospheric conditions. I once had a towel soaked in peroxide begin smoldering because I placed i on a metal table. The iron reacted with the peroxide. I immediately removed it from my shop.
     

  3. belizab

    belizab New Member

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    @joeym
    Thank you so so much for your reply! Thats great to hear. I wonder though why i felt the plastic container getting hot when i used 30% last time? Just really curious to know that :) Or maybe it wasn't getting hot just me felt that for some reason....
    But anyway thank you a bunch! I am not using it near any metal so that will not pose any threat.
     
  4. Sea Wolf

    Sea Wolf Well-Known Member

    Peroxide should be stored in a cool place and out of the light. If you open a container of peroxide, pour out some and close the container, it should not be heating up. Never pour anything back into the bottle. I have gallon bottles of 35% that are each stored in it's own 5 gallon bucket kept in the dark. Prevention ahead of time in case of any sort of leak. Most of what I use is either 40 VOL (12 %) or 27%. Still does a great job without it being as strong. If you are getting bottles with large caps without the pinhole, you could still make a pinhole in the lid with a small, heated nail to melt one. I would think though that the larger cap still has some sort of air pressure release built into it.
     
  5. belizab

    belizab New Member

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    Thank you for your answer @Sea Wolf!
    Now i wonder if i should also open and port out some in a dark place. Or can i open it in a light room pour out some, close it and place it back to a dark place to store?
    Right now i see some bubbles on the side of the container. The container itself is white so i think i need to make extra sure i store it in a dark place.

    Edit: I am sorry if this is a dumb question, however i want to understand the nature of H2O2 a bit more. I looked the stickied post here about it and Googled it aswell but better safe than sorry, i want to ask this here aswell.

    So i opened the H2O2 container (it didn't have any kind of air pressure release) in a semi dark place, poured out what i needed and closed the container. Now i am sure the peroxide in the container get in contact with oxygene while it was open, right? And it also got in contact with sunlight why i unboxed the container (the container is white and a very little transparent).
    The inner wall has some bubbles.

    Now i want to understand: because of the sunlight it was exposed to and the oxygene while it was open and i was pouring out what i need, will it start to decompose while the container is closed?
    If it does, what happens to the oxygene it produces in a closed container? Would it just explode? Or now that it is closed it does not decompose and thus not producing extra oxygene?
     
    Last edited: Apr 14, 2021
  6. Sea Wolf

    Sea Wolf Well-Known Member

    You can open it in regular room light. That's fine. Just store it in the dark when you are not using it. The bottle should be vented. I believe they are made that way. As peroxide decomposes, it releases oxygen. Those are the little bubbles you see. The venting on the cap prevents pressure from building up in the bottle. The peroxide itself will not explode in the bottle but pressure from the gas buildup can split the plastic container open and now you have a leak. If the peroxide is bottled properly, the cap should already be vented. Meaning it will not allow pressure to build up. Just do not pour anything back into the bottle and keep metal away from the peroxide you are using. That was what caused the damage in the article. A small bit of metal which acted as a catalyst for that reaction.
     
  7. joeym

    joeym Old Murphey

    Just for kicks and giggles...don't know how much chemistry you have ever had, but here is a little trivia. H2O2 is a very unstable chemical. It doesn't take much at all to oxidize that extra oxygen molecule to revert it back to H2O...water. Heat and light are the two catalysts. The scientific formula is actually 2H2O2, the molecules are always paired in the peroxide state. When you see peroxide labeled as 20 volume, 30 volume, or 40 volume, that means that is the volume in liters of oxygen that the peroxide will liberate per liter of peroxide upon oxidation. 40 volume peroxide is approximately 12% peroxide. The really unsafe peroxides begin at the 30-40 percent level. That's percent, not volume. 40% or above are radical oxidizers, and when placed in contact with other compounds, will release a tremendous amount of heat at oxidation. Occasionally, wooden pallets that are supporting drums of concentrated peroxide will catch on fire from a spill. The way that peroxide whitens is that it oxidizes the pigments in molecules that have color in skulls and bone. Peroxide plus heat shatters the pigment, resulting in a white (no color). Always be safe when handling peroxide. Sea Wolf gave you some excellent pointers. We have a participant in this forum named Cyclone who knows leagues more than me about chemistry. Maybe he will chime in at some point.
     
    Last edited: Apr 17, 2021
    Vulpes Vulpes, Sea Wolf and Mandi like this.
  8. Sea Wolf

    Sea Wolf Well-Known Member

    Really high percentage peroxide is also used as rocket fuel for just that reason. No idea if they still use it for that though.
     
  9. belizab

    belizab New Member

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    Yeah i have 30% not 30 volume. So the less safe one.
    Thank you for the thorough explanation!
    If, for safety's sake, i dilute it with water down to 15%, how long would that last? I read diluted peroxide can oxidize a lot quicker and become useless.
     
  10. joeym

    joeym Old Murphey

    Don't dilute it, but if you have the compulsion to do so, use distilled water.
     
  11. Sea Wolf

    Sea Wolf Well-Known Member

    Absolutely!! Someone on here did a dilution with tap water and got that bad reaction. Turns out the water itself had a high iron content and that was all it took.
     
  12. Vulpes Vulpes

    Vulpes Vulpes Active Member

    I read on a Chemical company website that hydrogen peroxide loses about 0.5% strength every year. I would imagine it looses strength much faster if it has contaminants in it such as after using it multiple times.
     
  13. belizab

    belizab New Member

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    Oh wow! Well i always diluted it a little when i cleaned bones and never had a propblem. But thank you for the warning!!
    0.5% a year doesn't seem that bad though!