I placed a 6" x 6" x 3/4" block of solid steel in the very bottom with foam around it to keep it from moving around. The steal is so dense that it holds its temperature for a very long time, and being that the ice chest is already well insulated from outside conditions, this makes for a VERY steady temperature in there, even when sitting in a really hot car for hours. I like to put it in the fridge for a while before I leave, that way by the time I put something in it, the temperature is just right. Obviously, the weight of it also keeps the ice chest from tipping over and moving around much. Since I don't actually carry this thing around, I'm not worried about the added weight.
![gallery_2_1138_531237.jpg](https://www.formiculture.com/uploads/gallery/album_1138/gallery_2_1138_531237.jpg)
I cut two pieces of the foam rubber packing material to fit inside perfectly. In this particular container I can fit nine test tubes on each piece of foam.
This is the first layer of foam and test tubes.
![gallery_2_1138_476769.jpg](https://www.formiculture.com/uploads/gallery/album_1138/gallery_2_1138_476769.jpg)
And here's the second.
![gallery_2_1138_643084.jpg](https://www.formiculture.com/uploads/gallery/album_1138/gallery_2_1138_643084.jpg)
To keep everything even more secure, I placed one more piece of foam rubber on top so the lid holds it all in tightly.
![gallery_2_1138_841948.jpg](https://www.formiculture.com/uploads/gallery/album_1138/gallery_2_1138_841948.jpg)
I also added a little thermometer/hygrometer in there too to help monitor the conditions.
![gallery_2_1138_301543.jpg](https://www.formiculture.com/uploads/gallery/album_1138/gallery_2_1138_301543.jpg)
I drilled holes in the top foam layer to fit my collection containers just right, in case I need to store some of them inside these also.
![gallery_2_1138_520423.jpg](https://www.formiculture.com/uploads/gallery/album_1138/gallery_2_1138_520423.jpg)
![gallery_2_1138_709012.jpg](https://www.formiculture.com/uploads/gallery/album_1138/gallery_2_1138_709012.jpg)
![gallery_2_1138_945049.jpg](https://www.formiculture.com/uploads/gallery/album_1138/gallery_2_1138_945049.jpg)
![gallery_2_1138_750499.jpg](https://www.formiculture.com/uploads/gallery/album_1138/gallery_2_1138_750499.jpg)
Edit: Added four new pictures.
Edited by dspdrew, June 20 2020 - 11:29 PM.