<P> Replacement bars were annealed and sandblasted to remove iron filings and other contaminants that would or could eventually cause the stainless steel to rust, and then dipped in nitric acid for protection . The "long term service behavior" of 316L stainless steel, according to a professor of metallurgy at Massachusetts Institute of Technology who had some involvement in the early stages of the restoration effort, was not known . The replacement bars of the iron grid system were insulated from the copper with a PTFE (Teflon) polymer resin tape produced by the DuPont company . </P> <P> A New York Times article from May 31, 1986 reported that inspection crews overseeing the restoration efforts had noticed several months earlier that a five foot long armature bar near one of the arms had been stamped with the forty names of the forty iron workers who had installed the armatures . The bar, which had to be replaced, was paid for by the contractors . Before being replaced, the bar was photographed; the image is in the June 1986 issue of Smithsonian magazine . </P> <P> The torch was removed from the statue on July 4, 1984 . An article in The New York Times from October 8, 1984, stated that the new torch is to be completed in the same manner that the old torch was made in 14 months by ten craftsmen from Les metalliers Champenois based in Reims, and that a workshop at the statue's base on Liberty Island had been made accessible to the public that month . </P> <P> Within the copper body of the statue is the structural support system consisting of a 97 - foot (30 m) central pylon, which is the backbone of the statue . The pylon consists of four girders with horizontal and diagonal cross bracing systems, which provide support to the secondary framework and to the armature, and a 40 - foot (12 m) long extension that supports the raised arm and torch . It had been a well - documented fact at least since 1932 (when the War Department reinforced the arm - shoulder structure), that the support for the shoulder of the upheld arm had been misaligned . Then, it was discovered that the arch that supports the head of the statue had also been misaligned . The cause (s) of the misalignments are undetermined, but a few hypotheses have been suggested . The first hypothesis proposed was that Viollet le Duc--the engineer who initially worked on the project with Bartholdi and who designed the structural reinforcement of the arm and the head (displayed in 1876 at the Centennial exhibition in Philadelphia) had died after having completed those two sections--and had employed engineering methods that differed significantly from those of the better - known bridge engineer Gustave Eiffel, who had finished the remainder of the work on the statue, and who is generally credited for the statue's remarkable structure . The second hypothesis was that the Americans, after having uncrated the different sections of the statue in 1886, incorrectly reassembled the structural framework . The third hypothesis is that the statue's creator, Bartholdi, was aesthetically dissatisfied when the statue was fully assembled and displayed in Paris on or just prior to July 4, 1884, and that he must have willingly sacrificed the structural integrity for his aesthetic vision . </P>

When was the statue of liberty torch replaced
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