First off, those Space Shuttle gaskets (O-rings) that failed during the infamous Challenger launch were made from something called FKM, which is a polymeric fluroelastomer. This is not the same chemical compound as PTFE (Teflon), which is a lubricant found in Tri-Flow. Incidentally, those Space Shuttle gaskets were surrounded by a special flame-proof putty that contained asbestos (which is carcinogenic). When the O-ring gaskets burned through, the resulting explosion of the rocket fuel is what blew up the shuttle. The fluorocarbons found in the O-rings and the asbestos in the putty never posed a health hazard in-and-of themselves during the disaster, of course.
Second, the melting point of Teflon is a whopping 621 F. It is not easy to melt this coating in a frying pan unless you leave the pan empty over the highest possible heat for quite a while. And even if you manage to melt it, it won't "burn," as you said. To get Teflon to depolymerize, you need temperatures above 1,000F! If you have "burned" Teflon in a pan, the chances are pretty good that it was actually the pan contents that burned, not the Teflon. Or perhaps the pan itself, or its handle.
Third, Teflon at room temperature, such as the material used in Tri-Flow lubricant, is almost entirely chemically inert, and it does not out-gas. It is not carcinogenic! Nor does it give off carcinogenic fumes, even when heated to the point where wood would start to burn.
Let's not forget that wood dust from many species of wood can be directly toxic when inhaled, and most wood dust is carcinogenic, regardless of the species. Luthiers and carpenters, who are exposed to wood dust in their work, need to be concerned about this. But should you be worried about getting cancer from the wood in your mandolin? Of course not! Playing the mandolin does not expose your lungs to significant quantities of wood dust.
Similarly, lubricating your tuners does not expose you to significant quantities of carcinogenic organic compounds, like those found in all petroleum-based household lubricants, nor does it expose you to significant quantities of Teflon, either, if you happen to use Tri-Flow. The vapor pressure of these lubricants is simply too low to pose a breathing hazard. Besides, as we have seen, Teflon is not even carcinogenic in the first place.
A little chemistry knowledge beats a lot of social media disinformation!
Bookmarks