Why didn't the flame on my thumb hurt?

[Adventure Helmet]

First of all, I know this was really stupid.

I was playing around with bug spray and a lighter (maniacally laughing as I shot flames from the can), and after spraying some flames I noticed something frightening and bizarre. A blue flame was silently curling along my thumb. I stared at it for a moment, and in a burst of panic swatted my hand to put it out. However, I realized I had felt almost no pain aside from a small stinging sensation, and that there was no sign of damage where the flame used to be. How did this happen?

[EdEarl]

The liquid evaporating from your thumb cools, and when it is a bit away from your skin flames.

[Enthalpy]

A spray flame would already be dangerous (...and fun) enough, BUT...

 

(1) Don't make it from a pressure can, which can blow if heated, and then the explosion of the evolving gas is really serious.

 

(2) Bug sprays are deadly poisons. Only for bugs in their normal condition and cautious concentration if you're lucky, but you can't predict what they produce in a flame. It could have been phosgene, cyanogene, an organo-phosphorus or any compound that tetanizes your lungs or blocks your central nervous system, and then, adios Adventure Helmet.

 

Of course, you knew how to extinguish that particular fire before you lit it, and had the corresponding hardware ready at hand with the procedure in mind, didn't you?

 

I know fire is fun, since I'm a scientist, and have played endlessly with it. I've also survived several such games just by bold luck. As an experimented survivor, the pressure canister and the poison are exactly what I would NOT play with. Please don't. Hope to read you again.