That’s a good point. I don’t make a habit of inhaling large concentrations of carbon dioxide but I am an experienced freediver and one of the first things you learn is how to suppress that desperate urge and almost panic to hold breath once CO2 builds in the bloodstream. As I understand it, bong users like to absorb resins and cool the gas to enable them to hold it in the lungs longer to absorb the psychotropic constituents in comfort, and adding carbon dioxide would work in opposition to that.
Just as a point of note, in my nomenclature of rocket propulsion and gas generators, “warm gas” is actually anything hotter than 500 K (~230 °C) and “hot gas” is anything over about 2500 K (over 2200 °C) so ‘bong gas’ is definitely “cold”. But even that at room temperature it will be much higher than the sublimation temperature of dry ice.
This is actually a fairly complicated scenario because heat transfer it not only depends on the temperature difference but also because the ‘bong gas’ presumably contains some significant amount of water vapor, which will transfer heat much faster than dry air. You might even get layer of frost trying to form on the dry ice block even while it is energetically sublimating (this is when you pour water on dry ice you see turbulence and sometimes even ‘snow’ briefly forming off of the ejecta) so there are multiple phases to consider for both media. You won’t see a 1 inch cube of dry ice disappear ‘immediately’ because there is more than a two and a half order of magnitude difference in density between solid carbon dioxide at sublimation temperatures and gaseous CO2 at the freezing point of water, and the rapid sublimation actually creates a kind of reverse Leidenfrost effect that helps to insulate the dry ice. The specific concentration in the resulting mixture will depend on the rate of sublimation versus the speed at which the ‘bong gas’ is being drawn over it and the enthalpy transfer between the ‘bong gas’ and dry ice but it will certainly be chuffing out large volumes of CO2, almost certainly enough to result in physiological response of someone directly inhaling it.
Speak for yourself. I’m trying to score some to make kief, and I’ve called every grocery store, every butcher shop, every farm supply store, every hardware store, and every (water) ice company in six counties. No dice. I’m going to have to drive nearly 100 miles to get some.
Pro tip: if your car breaks down on the way home, just grab 4 large pieces, put one under each tire, and you can just push the car down the road almost effortlessly (let a little air out the tires so the dry ice stays in place).
Carbon dioxide is widely used in the cannabis industry. Don’t strap on a mask or fall into a tank or confined space. Take precautions against chill injuries. Allow it to vent in storage and recognize it could displace air over time.
With those precautions, it’s pretty harmless for reasonable adults to play with in limited ‘handheld’ quantities, especially compared to other household chems like, say, oven cleaner, gasoline, bleach.
It’s been quite a few years since I used a bong (I use edibles nowadays), but apparently there are some new designs that use something other than water to cool the smoke. For instance this one passes the smoke through a coiled glass tube embedded in a glycerin substance that you freeze before use.
Physiological response? Sure. More than the physiological response of holding your breath 30 seconds or so though? That’s the part I’m skeptical about.
Average exhalation is about 4% CO2. Roughly 100 times that of typical room air. 20 to 40 mL of CO per breath being gotten rid of, that holding your breath prevents. At rest.
That was pretty much exactly the kind of device I was imagining Macgyvering up.
Not being a user myself I wasn’t interested in cluttering my search history Permanent Record w paraphernalia. I looked at DIYing using chem lab or HVAC parts, but they were pricier than I figured the OP would be interested in.