Specialty Chemistry Forums > Citizen Chemist
Ingredients needed to pressurize a empty bottle
billnotgatez:
Just now thinking about it and also wanting to make it safe and ease to do.
These come to mind
Baking Soda and Vinegar Chemical Reaction
https://www.youtube.com/watch?v=nRMyMIy7U6E
The classic elephant's toothpaste
http://www.periodicvideos.com/videos/elephants_toothpaste.htm
without the soap and color
This was from a quick search on GOOGLE
What do you think
EDsteve:
Yeah. I tried the baking soda some days ago. But the volume expansion is way to small. I have a few thousand bottles here. So i can't use 200ml vinnegar and 2 big spoons of baking soda for each :D
The ingredients for elephant toothpaste are pretty high. But i still have the feeling that the mini firecracker solution could work better, easier and much cheaper. Or are my feelings in the wrong direction?
After some more tinkering... the materials used in smoke bombs can do the trick. But maybe too hot for too long time.
I understand that a expanding volume in a closed space can be dangerous. So i can see why you want to be on the safe side with your information. The more efficient solutions are not for kids any more i guess... But i just thought i ask here before i go to the anarchists forum. Joking :)
Enthalpy:
A pump for bicycle tyres would be best, but I don't see how to seal the many bottles.
Natural yeast and something to feed it. I fear the rests will rot.
Yes, bicarbonate or some carbonate and some acid like vinegar. More concentrated acid would leave less water, so the bottle lifts more weight.
Firecrackers are not my first choice. The corrosive gas, especially SO2, may harm the plastic bottle over time.
Please protect your ears. Once with friends, we let soda bottles explode by pouring liquid nitrogen in and closing. My friend stayed deaf for half a day as he went too close. How much luck he had with shrapnel, I don't know.
Use scales to measure the amount of baking soda and acid so the pressure is reproducible. Cheap on eBay or Alibaba. Pour a clear excess bicarbonate to leave no acid damaging the plastic. You can prepare many doses in advance.
Did you check how durable the bottles are under sunlight? A protection by the pier can be useful.
Let a pier-review check your design.
EDsteve:
Hello Enthalpy,
and thank you for your answer.
--- Quote ---Natural yeast and something to feed it. I fear the rests will rot.
--- End quote ---
Last night i put 1g dry yeast and a bit sugar water (2cl) in one bottle . The result looks promising. Can you explain your "fear" about the rotting situation?
As already mentioned i tried the baking soda and vinegar(25%). But the pressure is way to small compare to the amount i have to put in each bottle.
--- Quote ---Did you check how durable the bottles are under sunlight? A protection by the pier can be useful.
--- End quote ---
Yes. I already built a hot water solar heater from empty bottles and they do last quite a while (more than 5 years in direct sunlight). But with the peer they will be covered from all sides. So that should be fine for a long time.
--- Quote ---Let a pier-review check your design.
--- End quote ---
I am still not exactly sure what it will become. Peer, floating platform, catamaran style boat or even an island. I will start small scale first and built two pontoons with 4m lenght and 60cm diameter. After collecting some experience how it behaves i will decide in which direction i go from there.
As you can see in the attachment. I am still in the beginning phase :)
Enthalpy:
--- Quote from: EDsteve on April 28, 2020, 12:43:01 AM ---I put 1g dry yeast and a bit sugar water (2cl) in one bottle. Can you explain your "fear" about rotting?
--- End quote ---
If you leave organic materials in a bottle for years, bacteria transform it into stinking and badly looking compounds. An exception would be if voluntarily introduced bacteria, for instance yeast, produce enough alcohol to kill all bacteria in the bottle. That's why you can keep wine for years (it will turn to vinegar but keeps safe for drinking).
I didn't check how much water is needed. While producing CO2, alcohol is made too, and some 14% alcohol stop the fermentation as the bacteria die.
--- Quote from: EDsteve on April 28, 2020, 12:43:01 AM ---I tried baking soda and vinegar(25%). But the pressure is way too small.
--- End quote ---
Vinegar is a very dilute acid, you need too much of it. Take a more concentrated acid, but please be careful. Prepare some means (the Ocean) to rinse yourself immediately. Wear protective goggles.
I prefer much the less strong polyacids like citric acid, tartaric acid
https://en.wikipedia.org/wiki/Citric_acid
https://en.wikipedia.org/wiki/Tartaric_acid
More protons hence gas per kilogram, less dangerous.
Oxalic acid is more caustic
https://en.wikipedia.org/wiki/Oxalic_acid
Battery acid (=sulphuric acid) is cheap and available but dangerous, and you need more or it for the same gas amount. Try to avoid it.
Can you compute the amounts? Introduce an excess of baking soda, as it shouldn't damage the plastic over time.
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