My cold plate leaked around the tubes that led into it. A refrigeration expert suggested that I pack it with 5200 on the outside. I was skeptical it would work, but five years later, it's still holding!
But, a salt water eutectic solution? That would be odd. Mine uses a 4:1 water to antifreeze mix. Either propylene or ethlyene glycol will work, but the former is, of course, less toxic.