Episode 115: Alaska Special 2

Air Date: April 15, 2009

Pykrete is bulletproof.

confirmed

The MythBusters demonstrated that a block of pykrete was able to stop a .45 caliber slug. In comparison, a block of ice was completely shattered by the bullet.

(Pykrete is a substance made of 14% sawdust or wood pulp and 86% ice by weight.)

Pykrete is stronger than ice.

confirmed

The MythBusters subjected ice and pykrete to a mechanical stress test where lead blocks were placed onto a cantilevered slab of each material to determine its breaking point. The ice failed when the weight exceeded 40 pounds (18 kg), while the pykrete had no problem supporting all 300 pounds (136 kg) of lead blocks the MythBusters had, and resisted several additional hammer strikes from Jamie before breaking. After this test Jamie made a slab of “super pykrete” (made out of newspaper instead of wood pulp). It held the lead blocks and Adam’s weight combined, even holding strong against repeated hammer strikes.

A working boat can be completely constructed with pykrete.

plausible

The MythBusters first tested how long ice, pykrete, and Jamie’s special “super pykrete” could last in warm water before melting. The super pykrete proved to last the longest, prompting Adam and Jamie to use that as their main building material. The MythBusters then built a full size boat out of the super pykrete 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 soon began to spring leaks as the boat slowly melted. At twenty minutes into the experiment, with the boat deteriorating, the experiment was pulled, and 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 predicted that an entire aircraft carrier could be built out of pykrete. They agreed to settle on a “plausible but ludicrous” conclusion.

A V-shaped snowplow is capable of perfectly splitting a car in half from front to rear in a head on collision, while the driver and the passenger both escape unharmed.

busted

Unable to find the necessary facilities in Alaska, the Build Team instead settled for a test location in Wisconsin. In their first test, the Build Team rammed a front engine car into the snowplow at 55 miles per hour (89 km/h). However, the snowplow failed to slice the car in two due to the thick engine block. In their second test, the Build Team used a rear engine car (made out of a front engine car with the engine relocated into the trunk), increased its speed to 70 miles per hour (113 km/h), and sharpened the edge of the snowplow to maximize the chances of slicing the car in two. Even though the front portion of the car was sliced in two, the snowplow again failed to cut through the engine block. Also, in both tests, the inflatable dummies representing the driver and the passenger did not escape unharmed, busting the myth.

17 Comments

  1. Assunta says:

    According to Wikipedia, the Aircraft carrier plan for pykrete involved using refrigeration units. I assume that they wanted to line the pykerete with cooling coils winding through its entire length (or embedded in the pykrete itself. That might make it last longer (or indefinitely) in warm waters…so long as the refrigeration units stay operational. Nice idea but probably only have limited applications. For example…if a country is running out of metal to make ships in a big war, they probably might as well consider using pykrete…specially if the war involves operations in colder waters. Peacetime uses might include building structures out of pykrete in cold climates (such is research centers in the Arctic or Antarctic). I think someday someone might eventually find a good use for this material.

  2. Bob says:

    They weren’t going to build a “boat” with Pykrete, the were going to build an artificial iceberg (with a 35 foot thick “hull”!) and use that as an aircraft carrier. The whole thing was going to be cooled with a network of galvanized iron pipes which would be pumping cold air all over the pykrete. So it would definitely have been viable ship. Slow and hard to maneuver yes…but it would have been hard to sink though. Probably have to use specialized thermal weapons to sink the thing…or damage the refrigeration units. Definitely plausible.

  3. SuperSparky says:

    About the refrigeration units…

    Not only were refrigeration units proposed, but the proposal stated super-cooling, not just to keep it frozen, but to keep it VERY frozen (several degrees below zero F). This would increase the strength and would minimize the melting issue. The ice would be so frozen it would be dry, even in the sun.

    The main problem wasn’t the logistics of building such a ship, but powering the cooling system itself. It involved far too much fuel oil, which was counter intuitive as it would require large heat generating engines to generate the necessary power.

    The feasibility of a pykrete ship is actually better today, due to nuclear power, and there are a lot of high-tech insulating materials available to insulate the crew and the elements (ocean/air) from the pykrete itself.

    There’s even a possibility of better filler materials than wood product (sawdust, or paper).

    However, there is a BIG BIG BIG problem. All you need to do is drop thermite on it and it’s a hydrogen fueled bomb. DOH!

  4. tim says:

    The pykrete ship was actually built as an experiment(in a smaller scale), there was construction of a structure, 60 feet long by 30 feet wide and 19.5 feet high on a lake in the Canadian Rocky Mountains – Patricia Lake in Jasper, Alberta

  5. Heather says:

    Does anyone know where in Wisconsin the car splitting myth took place?

    • Marsha Stoner says:

      It took place across the highway from my house, at MGA Proving Grounds just south of Burlington, Wisconsin.

  6. Yhet says:

    If you watched the episode, they mentioned in the show that the car splitting myth happened in Alasaka not in Wisconsin

  7. dan says:

    using real pulp not wood chips saw dust may improve results newspaper is not a viable sub also refrigeration and the thickness would help

  8. george park says:

    yes, you tried splitting the car at 70mph,but only the car was moving.even the car going at 70mph,it wouldn’t have near the energy that the snow plow would have at half the speed.mass (weight)is the main difference. mass x speed=force. so do it right guy’s most snow plow’s are usually driving at 45 to 50mph,and most car’s at 55 to 60mph.

  9. SchoolKid says:

    Thanks for the info guys as I need some on “super pykrete” for a school project. if you guys could provide some numbers and stats(tensile strength, density,crushing strength etc.) that would be great! Thanx

  10. Jim Guthrie says:

    As noted above, the concept was tested in Jasper National Park in Canada. Churchill was especially enthusiastic about the idea. The test was technically satisfactory but the main rationale (to provide impregnable “stepping stones” to transfer aircraft between the UK and North America, and to provide bases for ASW and shipping convoy air cover) was overcome with the implementation of longer range bombers.
    The remains of the test still remain at the bottom of the lake.

  11. Yvan says:

    what is the right solution for the pykrete? thanks

    • michael says:

      I think it is 14% sawdust by weight

  12. JOSECARLOS says:

    IM DOING THIS AS MY SCIENCE FAIR PROJECT =D

  13. Logan says:

    they should retry the snowplow myth with an electric car (no engine block)

    • Dean says:

      News report from Perth Australia says car split lenghtwise by palm tree in high speed crash. Dated 20 december 2011. Police described crash as horrific

  14. armi says:

    Have the plausibility of Pykrete made from newspaper and sawdust combined ever tested? Just a thought, if frozen newspaper can hold up for 30 minutes, what do think the two combined can create? I would like to see if this concept actually work.

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