The amount of copper used to build the vessels for the Temple was so massive and unprecedented that it completely surpassed human ability to measure it. The primary approach among commentators is that King Solomon eventually stopped trying to weigh the items altogether. Because of their sheer number and immense weight, he simply gave up and abandoned the effort to count them.
Other perspectives suggest that rather than giving up on measuring, Solomon was actively storing and physically placing the items. According to one view, he brought the vessels from the location where they were cast and set them down in their designated spots inside the Temple [רד״ק]. Another perspective, based on a parallel account in the Book of Chronicles, explains that Solomon intentionally manufactured a much larger quantity of vessels than was needed for immediate use. He then placed this surplus into the Temple treasury, storing them away as a preparation for the future [מלבי״ם].
Ultimately, the vast collection of copper items was left exactly as it was, without anyone ever finding out its exact weight. This concluding thought serves as a conceptual repetition of the initial events. The idea is repeated in different words to add clarity and to emphasize just how incomprehensible the total amount of copper truly was [מצודת דוד].