Will home made candle flame vaporizers cause combustion?

I made a home made vaporizer using a metal sauce cup you get from restaurants heated with a votive candle(little two inch candles that everybody has). It works great, or so I thought. I did a little more research and leaned how you must the temperatures just right to vape thc but not combust the bad stuff. I know a candle flame is around 2500 farenheit. MJ needs to be heated no higher that 392F in order to vaporize without combusting. So, does that mean using a candle flame to heat a metal cup will most definitely cause the weed to combust and ruin the pure vaping effect I want? Would I be more getting the bad stuff and are there any tell-tell signs that your weed is combusting, such as seeing a certain color vapor or actual smoke becoming visible inside the vapor collection chamber?

i think the temp info for the candle you got is way off base. silver melts at 2100f and you could hold pure silver wire over a candle for a month and just burn your fingers. candle flame probly closer to 700f (guess). if using this method to medicate i think the soot may likely kill you. i would certainly recomend a much cleaner heat source. not a doc but hope this helps.

sorry i didnt actually answer your ? earlier. i dont think so but if your concerned temp can be adjusted by increasing or decreasing height of your cup. is your material ashy or just crispy crunchy?