The answer to this puzzle is a two word phrase (13 letters in total) where the first word starts with W. Good Luck! ;)
Hint 2 (more decisive)
Apply "hint 1" on all three grids. The small squares shows you how.
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So this is a bit of a long shot, but is the answer
As Mattia guessed in his answer, you can get the chemical symbols Ag, Au, Cu, and Sn by swapping the letters in the three grids using the pattern at the top of the image and then tracing the path shown at the bottom of the image. These symbols correspond to silver, gold, copper and tin. Gold, silver and bronze (an alloy of copper and tin) are typically used in competitions as the winning prizes for first, second, and third place, respectively.
When the competitors are awarded their prizes, they are often standing on a platform or podium, with gold standing on the tallest platform, and silver and bronze standing on slightly shorter platforms to either side. The three grids are meant to visually resemble this "Winners Podium": Silver is found on the left (Ag), gold on the top (Au), and bronze on the right (Cu and Sn).
After having swapped all the letters in the three grids, we can overlap the path and the grids reading the string "agaucusn".
We can also write it as AgAuCuSn, i.e. Ag (Silver), Au (Gold), Cu (copper), Sn (tin).
Among these four elements, gold has a lower melting point, so I guess that WELDING SOLDER is Made for three only!