Dry ice

Used Dry Ice in our coolers when exploring Baja,we found that un wrapped it tended to get so cold that it cracked the inner liner of the coolers.

We always wrapped the blocks with 4 or 5 layers of newspaper. The thicker the insulation, the slower it will sublimate.Making it last longer,but still keeping everything around it very cold.

I have used it on several long canoe trips, it needs to be wrapped (I used newspaper) If I am camping with the RV I usually just go get ice as needed. Dry Ice will freeze anything near it and is dangerous around children as it can cause a bad burn.

I put dry ice in a cooler one time. Stuff froze. Even my beer, or at least the water in it.

I have been thinking about using dry ice too. If I put dry ice in my cooler then place a bag of ice on top of it will it freeze the ice? Try to keep ice longer for drinks.

I put the dry ice on top of the food and wad newspaper. Closed and sealed, it lasts 48 hours.

A piece of corragated cardboard would be good, but not necessary. Some foam coolers will get very brittle from the extreme cold.