# Pykrete



## JustCliff (May 21, 2011)

http://en.wikipedia.org/wiki/Pykrete
I have been meaning to post this but time has gotten away from me. Another post reminded me of this so here it is.

Pykrete
Is a very durable mix of water and sawdust. 14% sawdust to 86% water. The reason for me bringing it up are not so much the structural properties but the thermal properties. 
Pykrete has a low thermal conductivity. Meaning it take forever to melt. Making it ideal for a cold storage cellar. I had thought about making some 24"X12"X6" molds for making the big Pykrete blocks that I could stack along the walls from floor to ceiling And maybe a stack in the middle or even a cabinet made of it in there to keep milk and other things real cold. 
If the cellar roof was insulated with a good foam coat of insulation, I think the northerners could probably go season to season with a lot of ice left.


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## Navajo (Mar 4, 2013)

The ground would have to stay frozen....Even our deep root cellars don't stay that cold, ice floors melt by July/ August

http://en.wikipedia.org/wiki/Pykrete

The mixture can be moulded into any shape and frozen, and it will be extremely tough and durable, as long as it is kept at or below freezing.

In 2009, the Discovery Channel program MythBusters episode 115 tested the properties of pykrete and the myths behind it. First, the program's hosts, Adam Savage and Jamie Hyneman compared the mechanical properties of common ice, pykrete and a new material specially created for the show, dubbed "super pykrete", using newspapers instead of woodpulp. Both versions of pykrete indeed proved to be much stronger than the chunk of ice, withstanding hundreds of pounds of weight. The super pykrete was much stronger than the original version.

The MythBusters then built a full-size boat out of the super pykrete, naming it Yesterday's News, and subjected it to real-world conditions. Though the boat managed to float and stay intact at speeds of up to 23 miles per hour (37 km/h), it quickly began to spring leaks as the boat slowly melted. After twenty minutes the boat was deteriorating, and the experiment was ended. The boat lasted another ten minutes while being piloted back to shore. Though the boat worked, it was noted that it would be highly impractical for the original myth, which claimed that an entire aircraft carrier could be built out of pykrete.[12] Their conclusion was "Plausible, but ludicrous", since building vessels out of tens of thousands of tons of the material that would sink without being kept cool.

The MythBusters test was done at or slightly above freezing temperatures and generally proved that pykrete as a material was not simply better than other alternatives. Their vessel did not contain refrigeration units keeping the pykrete cold as the original plans called for and the boat had a much thinner construction than the ships proposed in World War II.


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## roselle (Oct 20, 2013)

JustCliff said:


> http://en.wikipedia.org/wiki/Pykrete
> I have been meaning to post this but time has gotten away from me. Another post reminded me of this so here it is.
> 
> Pykrete
> ...


A couple months ago...This big container of "pykrete" appeared in my freezer...My littlest one had decided to make some...I had never even heard of it before, but he was singing the praises of it...Every day...A new surprise around this house! I asked what was he gonna do with it...He said "Play with it! It's really cool stuff!"


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## roselle (Oct 20, 2013)

Well after writing about my little son and his pykrete...It just came to me what my children are....

They are "Free Range Children!"


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## jeff47041 (Jan 5, 2013)

I have been thinking of building a concrete underground cellar with a floor drain. I thought of making a bunch of forms for pykrete, but only 3" x 24"x 12". 
Some years, we have very mild winters, so I thought the 3" thickness could help me guarantee to get them frozen solid.
I thought that lining the floor with a few layers, and stacking the walls a few 12" blocks thick, it would maybe stay cool most of a year. 
It would have a concrete ceiling, several inches of polyiso roof insulation, a roof, then at least 6" of dirt.


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## Tirediron (Jul 12, 2010)

Maybe pykrete combined with this type of device would really work well, keep in mind that the dark sky even in summer can absorb a lot of heat (cooling effect)
http://fourmileisland.com/IceBox.htm


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## Ezmerelda (Oct 17, 2010)

roselle said:


> Well after writing about my little son and his pykrete...It just came to me what my children are....
> 
> They are "Free Range Children!"


That's the best kind!


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