3/16 of an inch; this was the total thickness of Dowmetal that protected the balloonist from the uncertainties of the stratosphere during the the 1934 and 1935 National Geographic Society - U. S. Army Air Corps Stratosphere Balloon Flights. The Dow Chemical Company in Midland, MI touted their magnesium alloy as the "World's Strongest Light Metal" (it was only two-thirds the weight of aluminum and less than one-quarter that of steel) and for that reason, the Explorer Gondolas were constructed of Dowmetal. The spherical shape of the gondolas would allow stresses to be uniformly distributed. The gondola constructed for the 1934 flight was 100 inches in diameter and only weighed about 700 pounds empty. As described in last week's discussion, this gondola was destroyed during the 1934 crash of the Explorer Balloon. The gondola constructed for the 1935 flight of Explorer II was 109 inches in diameter, but weighed only 637 pounds empty. The decrease in weight was realized when shelving used to support the weight of scientific equipment used during the 1934 flight was eliminated. During the 1935 flight of Explorer II, the scientific equipment was bolted directly to the side walls of the gondola.
Pieces of the Explorer Gondola have been on display at the United States Air Force Museum in Dayton, OH for several years. The Explorer II Gondola is on permanent display at the Smithsonian Air and Space Museum in Washington, D.C.
In order to promote their part in the Explorer Balloon Flights, Dow Chemical produced commemorative coins (tokens) made of Dowmetal. The tokens measure 1 3/8". Examples can be seen in the attached photo. Typically, the tokens are extremely oxidized and nearly black (as shown in the middle example) when offered for sale. Using proper cleaning agents, the oxidation can be removed.
For many years, Dowmetal Explorer II tokens were considered extremely rare and sold for as much as $1000. Ebay and the discovery of a cache of the tokens have considerably decreased their value.
In next week's installment of The Souvenirs and Collectibles of the National Geographic Society - U. S. Army Air Corps Stratosphere Flights, we will discuss NGS Presentation Flags carried on the flights.
In your article you mention removing the oxidation, which process has best worked for you?
Awesome your my hero worked like a charm! It was so dark it wasn't ledgable Now I can actually read it and display it. Thanks for sharing your knowledge Charles