We use sand baths at work to cal check thermal switches & various temperature elements. Depending on sensor mass, it can take hours to stabilize with this.
If we were using salt bath, it would take under a minute. But salt is a consumable, and sand is useful forever.
You know how that goes from a company standpoint..
Pay us hourly for a week round the clock to cal check 108 thermocouples, instead of a few hours, with upgraded equipment(that cost chump change in additional funds).
But hey, at least we're not mortgaging the site for inductive hogwash, or guessing with flame and color charts!