Old timer I know, tank driver in korean war, used to cool beer with the tanks fire extinguisher.
One day the tank caught fire.............................
but at least they had cold beer for the weiner roast.
dry ice website that says to make an insulated box with dry ice in it... and that takes 10 minutes to freeze up. That is interesting, because a towel would be quite a bit easier! thanks!
Anybody that is looking for one I have a Ridgid 2500r superfreeze for sale $1200 plus shipping.
I use the General kit. its simple and very well built this is a tool that saves me a lot of time. The compressor type units are nice but unless you plan to use one alot not worth the investment plus its not a tool that you want bouncing around in your truck. Both tools do have the same drawback if the water is moving you will not freeze it.
Wait a few minutes and check a faucet. You know the rest. Buying dry ice is cheap. Far cheaper than buying a kit I would use once every ten years.
You can also rent freeze kits to see what you think of them.
In stead of smashing the dry ice what it you took two blocks and formed a groove in each one to match half the OD of the pipe, then sandwich the two pieces of ice around the pipe to encapsulate it fully and wrap with blanket insulation. Much more surface area contact this way I think and better heat transfer out of the pipe and process fluid. Haven't tried it but this would seem to mimic the setup on the superfreeze blocks or when using CO2 with the blankets.
As far as what happens if you lose your freeze in the middle of the job well I think you know the answer to that. We calculate how much CO2 is required for the estimated job duration and then double the amount on hand so as to have enough to extend the job length by twice the estimated duration, just in case complications develop. Sounds excessive i know but where I do freeze seals there is no room for error and they better not fail.