Thank you all for your answers.
Now I have a doubt: Is ignition by spark or by fuse in comercial bulbs?
Well... I intend to use aluminium foil as this is what I have handy. (I eat a lot of chocolate.) Of course magnesium foil or zirconium wire would be better, but where to get? I also think some of the big bulbs avaible from manufacturers were filled with aluminium foil.
Yes, I will coat the glass. I think laquer for wood or metal will suffice, I will try to get a thick one.
Final achievment of the experiment should be bigger bulbs that the ones avaible comercially. But I will begin with small ones out of safety considerations.
Steve, is that wire wool the thing used to clean/scrub hardened residues from dishes?