umm rust is not toxic. And if the UTH covers a larger area, i dont think its likely for the tube to get too warm at the bottom. the warmth is spreading out over the surface area of that tube, since it has high thermal conductivity. With this shape, high thermal conductivity just doesnt mean that when it touches the UTH, it will get as hot as the UTH at the bottom of the pipe. It means that heat gets distributed in the whole structure of the pipe.


so i see no need to throw it out, you might as well keep it. You might test how warm it gets when you dig it deep into the substrate when the snake is taking a bath or something. worry about rust if rust appears, since you can easily sand it off. sanding off some fresh rust is easier than sanding off edges. then you can still apply a coating.