I held it right up against the glass, but I think that actually might not be such a great idea, because it started to crack a little from the heat.

I left the flame there tell it was completely full and white inside, but keep in mind I put the cap back on if my lungs reached their capacity, exhailed, and finished it off.

With that being said, for the cap I did something a little different, which I now realise would have kept it from cracking, had I used it correctly. I kept the hole I had initially made for the pen tube, and at first, kept my finger over it when I was heating the weed. Then the bulb cracked (although only slightly) from a combination of the heat, and the pressure of smoke on the inside. so then I realised if you keep the hole uncovered, the pressure can escape, but not that much vapour seeps out, so it didn't crack anymore.

I still can't figuire out why it didn't work for you though... cause that's alot of weed to vaporise. But, I've also heard other people complain about it, so who knows... Personally I prefer my bong, but the vape's too good for when I'm at home and I don't wanna the rents pissed.

Oh, and also, I used one big mother fuckin' lightbulb. at first I had this little one, and thought it would be chill cause it was one of those green color lights. Then I looked behind it on the shelf and was like.. "Ohhh shit." It was one of those big round ones.

But since that one's broken, I just have a regular one I'm making right now..

Peace

Edit: Burning plastic!? describe the lighbulb, it sounds like you used the wrong kind, but i dunno yet. And no, no you didn't, you have to breath in alot of one particular carcinogen to get cancer, atleast to my knowledge.. like asbestos for example... smoking random shit apperently can kill you, chemicl depending though.