I was concerned that using a mugwarmer instead of a hotbed wouldn't be as effective, so I left it a little longer.
Luckily, I'd worried for nothing. Just look how smooth and shiny it made that part! Far too much in fact -- it turned it into jelly :D Luckily I just used a scrap piece!
Further experimentation required.
 People reccomend 15-20 MINUTES. this was at least two HOURS.