Hydrogen-based fireworks?

[ScienceNostalgia101]

I've got a whole bunch of half-drained batteries and wood ash around, and I was considering making homemade hydrogen-based fireworks with electrolysis for Canada Day.

 

1. I tried testing the wood ash for hydroxides by putting them in an aluminum can and mixing them with water, but it didn't dissolve the can. Are carbonate compounds effective enough electrolytes? Are they safe to use?

 

2. Do balloons store hydrogen reliably for days? If so, does it depend on the material? If not, do you know of what else can be used to store them that can also be used to pump the hydrogen into balloons? Or if not balloons, do you know what else would be lightweight enough to float when filled with hydrogen? (I'm not talking on the scale of blimps here, I'm talking anything the size of balloons or only slightly bigger.)

 

3. I was also wondering how to light them once they're in the air. Would throwing a sparkler do the trick, or would it be better to soak a thin string attached to the balloon in gasoline? Would the fire be out before the string hits the ground? (I could do this well away from any houses or trees, but ideally I'd want to avoid the hassle if it's safe enough.)

[hypervalent_iodine]

I realise this is too late for the intended purpose, but to answer your question regarding balloons: no. Normal balloons are not good at keeping in hydrogen. You can mitigate it partly by using helium quality balloons or by placing one balloon inside another, but you will always get leakage. I wouldn't trust either set up to keep the hydrogen inside for days.

[ScienceNostalgia101]

Eh, it's fine, turned out my hometown went ahead with that municipal fireworks display after all. Forgot all about this thread after that until now.

 

Another question, for future reference; would glass store the hydrogen more effectively? If so, and if I put a balloon full of air over the tip of the bottle, would it become 50% hydrogen by diffusion? (Or alternatively, more than that because hydrogen is lighter than air?)

 

And even if so, would there be a way to get the concentration higher than 50%? Would a tube of water inserted underneath the balloon, filling the bottle, force hydrogen into an empty balloon wrapped over the tip?

Edited July 16, 2017 by ScienceNostalgia101