After reading all of the critical reviews that said "doesn't keep my coffee hot enough" I sure wasn't expecting mine to melt.  The plastic around the edges of the warming surface bubbled and cracked after being on for about two hours.  I used it once, successfully, and it kept my coffee piping hot from just after breakfast until just before lunchtime, maybe three hours.  I noticed that a little of the black paint or surface had flaked off the warming plate, but I was still very pleased with it at that point.  Cosmetic flaws don't bother me.  Then the second time, it melted.  Be VERY careful with this device and monitor it VERY closely.  Also recommend NOT putting it on any surface that could be damaged by heat, as the outsides and the bottom were burning hot to the touch - like I could pick it up but it was very uncomfortable.  But it will definitely keep your coffee hot, at least until it melts!