even though the welder uses them to print the seed phrase
So you gave your seed phrase over to someone else and had them engrave the plates for you? That's a big mistake! If you have any coins on the seed phrase you handed over you should move them ASAP.
I have to say as well, those weight plates look like cast iron without any protective coating, and they already look pretty badly rusted. I think there is a risk of your seed phrase becoming illegible over a long enough time frame here.