Tchild wrote:The current apologetic rationale is that the plates were made of tumbaga ( non-specific alloy of gold and copper with anywhere from 97%-3% gold content).
Tumbaga is the natural apologetic explanation because the "witnesses" who lifted or hefted the plates (covered of course) estimated their weight from about 40-60 lbs. So, it stands to reason from the LDS mindset, given the dimensions of the plates, that the gold content must have been rather low. Also, tumbaga was used extensively by pre-columbian cultures in central and south america.
Why don't apologists factor in the possibility that the plates were a prop made of tin that could readily be found at a local cooper shop, such as was owned and operated by a Joseph Smith Sr.?
What is the weight of tin with the same measurements as the plates? About 40 lbs.
Let me have another go at that calculation, except I'll use copper:
Copper has a density of 8.94 grams per cubic centimeter, and the plates were described at being 8" x 6" x 6".
8 x 6 x 6 inches = 20.32 x 15.24 x 15.24 centimeters which equals 4719.47 cubic centimeters.
4719.47 cm3 multiplied by 8.94 grams per cm3 = 42,192 grams = 41.192 kilograms = 92.8 lbs.
So, if we assume that these plates were not gold, but rather a 97% copper +3 % gold alloy, we can see the weight drops to less than half, but that weight is still more than 93 pounds. If we allow a 100% air gap (plate thickness to air gap ratio) then we can bring the weight down to ~46 lbs, right where the apologists need it to be.
But then we go back to the problem with the box, which could not have been made water-tight. Any substance which is 97% copper is gonna have a helluva time with oxidation (corrosion). Plates made of this material may physically be able to last for thousands of years, but any writing upon them would surely be so badly eroded by the patina of copper oxide as to make it difficult to read.
I'd say the apologetic
Tumbaga Gambit causes as many problems as it solves. Which is to say it is in good company with many other apologetic explanations hastily concocted with the vain hope of saving the church from its own sordid history.