Bradbury called.
He wants his number back.
A careful study of The Testimony of Eight Witnesses shows that these men who handled and hefted the plates and saw the engravings thereon would notice that they did not state that the plates were made of gold, only that they "have the appearance of gold". This suggests that they were either composed of another metal or alloy plated with gold, or were composed of an alloy of gold.
That they were definitely not made of solid gold is proven in two ways: (1) As related in Investigating the Book of Mormon Witnesses by Richard Lloyd Anderson, William Smith, in an 1883 book, wrote: "I was permitted to lift them as they laid in a pillowcase, but not to see them, as it was contrary to the commands he had received. They weighed about 60 lbs. according to the best of my judgment." That would be much too light for plates of solid gold in the dimensions described by Joseph Smith and others. (2) In the 1879 Saints' Herald interview of the former Emma Smith, she stated: "The plates often lay on the table without any attempt at concealment, wrapped in a small linen table cloth, which I had given him to fold them in. I once felt the plates as they thus lay on the table, tracing their outline and shape. They seemed to be pliable like thick paper, and would rustle with a metallic sound when the edges were moved by the thumb, as one does sometimes thumb the edges of a book." Sheets of pure gold, if bent, would not spring back flat again.
There are many alloys of copper. In an 1884 sermon, William Smith, who was not among the eight who saw the plates, stated: "When the plates were brought in they were wrapped up in a tow frock. My father then put them into a pillow case. Father said, 'What, Joseph, can we not see them?' 'No. I was disobedient the first time, but I intend to be faithful this time. For I was forbidden to show them until they are translated, but you can feel them.' We handled them and could tell what they were. They were not quite so large as this Bible. Could tell whether they were round or square. Could raise the leaves this way (raising a few leaves of the Bible before him). One could easily tell that they were not a stone, hewn out to deceive, or even a block of wood. Being a mixture of gold and copper, they were heavier than stone, and very much heavier than wood."
I'd like to know where William got the information about the "mixture of copper and gold", and whether "mixture" meant a copper-gold alloy, or copper or some copper-based alloy plated with gold. In any case, "435 pounds" presumes a metal composition that is not supported by the historical evidence available. In other words, "435 pounds" is urban legend, designed to enable ignorant mockery.