Aug 20 2013, 5:31pm
There is a wonderful snout of depth in Tolkien's works! That is the greatest part of their appeal to me, personally.
No such thing as "too deep"!
However, we can sometimes touch the bottom.
In reference to the visuals you have provided, it would seem that you are speaking of the Peter Jackson adaptation, note the use of the word --adaptation. There could be many different answers, depending upon the version in question, and I will attempt to answer some of them.
Going from PJ's adaptation, he could have used the heat, merely to activate the power if the Ring, or he could have just forged it at that instant, using non-physical means. There is really a lot to be speculated upon in this version, as it leaves much to the imagination. There is no time to cover every fact in a movie, and something is lost, inevitably.
If we dig into the books, we can possibly get a more comprehensive answer. It is said that it WAS forged in Mt.Doom, but that it was chanted over by Sauron, and that the Elves overheard it. There are many ways to reconcile the facts, perhaps he forged the Ring first, in intense heat, to make it harder to destroy? What good would it be if it was easily destroyed? Then he might have gone back to the forges, to put his power into it, or to be near the Rings he wanted to enslaved?
There is still much doubt, as the exact process is not elaborated upon, but this is certain, he forged it in Mt. Doom, and chanted over it in the forges of Celebrimor, revealing his designs to the Elves. How, or in which order he proceeded, is unclear, but it is to be taken as true
As to armor, the books say nothing, so it was left to PJ, who has left the explanation open to us.
No RIGHT, or WRONG answers, just different interpretations if the unknown.