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Making dry ice at home

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Re: Making dry ice at home

#31

Post by MostlyStable »

JohnFen wrote: post #7
pmx wrote: post #2

it's actually much easier than this makes out. Sodastream bottle, some kind of cloth like a tea towel, pillowcase or even a sock over the end, let 'er rip and you have a chunk of dry ice.

At that point, why not just buy the dry ice directly? It would surely be cheaper...

Well, one reason is that you can store CO2 in a tank for a long time, in lots of conditions, easily and with basically no cost. So, if either A) no stores convenient to you sell it or you need it at more flexible times etc, or for some other reason you want to it on demand at a price premium, it could be worthwhile.

But, based on the write-up here, it sounds like he was doing this out of curiosity, at which point yes buying the CO2 would sort of defeat the point.

Of course, one could also ask the same questions about buying the baking soda and acid. There is no clear delineation at which point before which it's "made from scratch" vs. "store bought".

Sounds like the answer in this case was: the person in question thought that starting from purchased baking soda and acid was an interesting problem to solve, and starting from bottled CO2 was a boring problem to solve and starting from some precursor to baking soda and acid was too much of a pain to solve.

Re: Making dry ice at home

#32

Post by knodi123 »

amelius wrote: post #10
pmx wrote: post #5

Earlier quoted context omitted.

indeed! I also don't dig my own well every time i wish to boil water for tea!

“If you wish to make an apple pie from scratch, you must first invent the universe” -- Carl Sagan

rating: 2 stars

I substituted brown sugar for primordial quarks, and I used an air fryer instead of a big bang. apple pie came out mushy and bland.

Re: Making dry ice at home

#33

Post by JohnFen »

londons_explore wrote: post #28
at_a_remove wrote: post #17

Dry ice has become really quite scarce in the last five years. It was explained to me at the ice shop I used to visit that there were changes in some shipping regulations, not too sensible ones, that resulted in a much higher price and a bunch of people just dropping out of the business. Indeed, that place finally got out of the dry ice business as well. Airgas has some pretty tight hours and in smaller towns, they d…

In the UK and most of europe, dry ice is limited to industrial/scientific uses. No retail shops sell it.

That's a real shame. It's very useful stuff!

Re: Making dry ice at home

#34

Post by tombert »

cellshade wrote: post #23
gambiting wrote: post #22

Earlier quoted context omitted.

Honest question - where do hell people buy dry ice from like it's the easiest thing ever, I've looked into it and there was no one within hundreds of miles from me who would sell to private buyers. UK here.

Here in the US, you can buy it at the supermarket.

I've had trouble finding it in NYC; my initial idea for doing SodaStream refills was to simply buy the appropriate weight of dry ice and fill the canister by unscrewing the top, but I wasn't able to find any dry ice available for purchase.

For those curious, I ended up finding a welding supply store that just sold pure CO2 in a tank.

Re: Making dry ice at home

#35

Post by omginternets »

londons_explore wrote: post #28
at_a_remove wrote: post #17

Dry ice has become really quite scarce in the last five years. It was explained to me at the ice shop I used to visit that there were changes in some shipping regulations, not too sensible ones, that resulted in a much higher price and a bunch of people just dropping out of the business. Indeed, that place finally got out of the dry ice business as well. Airgas has some pretty tight hours and in smaller towns, they d…

In the UK and most of europe, dry ice is limited to industrial/scientific uses. No retail shops sell it.

"The US innovates; the EU regulates", as the saying goes. Makes me sad...

Re: Making dry ice at home

#36

Post by knodi123 »

wincy wrote: post #30
upon_drumhead wrote: post #12

Earlier quoted context omitted.

They often don’t advertise its availability but most grocery stores in the US do sell it. It’s very useful for road trips, power outages, and shipping perishable items.

On Halloween, my grandma (I’m in the US) would dress like a witch and use dry ice carbonate homemade root beer she’d dole out to kids from a giant bubbling black cauldron. I thought grandma was an actual witch for a while there.

homemade root beer is pretty difficult to do well!

Re: Making dry ice at home

#37

Post by RC_ITR »

wrs wrote: post #26

Our chem lab in high school (in the 80s) had a CO₂ tank attached to a metal cylinder similar to the 3D printed one shown here. You just hooked it up and turned on the valve to create a puck of dry ice. So if you need it frequently and have trouble finding it for sale, maybe look for the modern equivalent. (It being high school, about 5% of the dry ice created was used for legitimate chemistry purposes.)

One of my craziest learnings as a non-Chemist taking my basic college chem was that liquid nitrogen is usually much cheaper than milk on a volume basis.

It makes sense ofc - nitrogen is our most abundant gas after all, but it still really blew my mind for something that seemed so exotic.

Re: Making dry ice at home

#38

Post by Retric »

thmsths wrote: post #16
JohnFen wrote: post #7

Earlier quoted context omitted.

At that point, why not just buy the dry ice directly? It would surely be cheaper...

This may be a dumb question, but how do grocery stores store the dry ice they intend to sell? This stuff has to be kept very cold to prevent it from sublimating. Do they just keep it in an insulated box with a vent and just accept that they will loose some of it?

Yea it just vents. This might seem odd but it’s cheaper than maintaining a cryogenic cooling system. Very well insulated containers are cheap and heat gain only occurs along a surface where they’re storing a large volume. So losses per day end up being trivial when they’re only paying ~0.5$/pound and selling it for 3$/pound.

Re: Making dry ice at home

#39

Post by fnordpiglet »

I tried to make a TEC chip dry ice maker. It was hard to manage all the heat the TECs made. I ended up with an elaborate water cooled device with a large copper block acting as a thermal mass interfacing with a TEC tower and 3d printed insulated chambers etc. I got a little bit to freeze, and I could get temperatures close to freezing nitrogen, but eventually my wife made me clean up my huge mess in the dining room.

Re: Making dry ice at home

#40

Post by sneak »

gmiller123456 wrote: post #19
HWR_14 wrote: post #11

Earlier quoted context omitted.

It's dangerous enough (suffocation, freezing) that there are plenty of reasons to require an age minimum. I don't think I've seen dry-ice in supermarkets since COVID started, but I haven't been looking much either.

Never disappeared around here. A lot of people rely on it to get their frozen stuff home without thawing out. So it's more available in rural places where people will have a long drive home.

Ahhh, that makes a ton more sense now. As one of the aforementioned soda-bottle-bomb-making-youngsters, I had no idea what people's legitimate uses for it were outside of party tricks.
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