It caught my attention 30 years ago! The first time I saw it, I was mesmerized! All that gas from a short weld bead and it just kept coming and coming! It makes you think of how small the hydrogen atom must be to pass through solid steel.
The demonstration doesn't work any wheres near as good with the new E7018-H4R because they are formulated to resist moisture pickup. I have to say, the new flux works pretty good.
I've seen the demonstration on U-Tube as well. There are several fellows that have put it on the internet.
Best regards - Al