Originally posted by Matt
Am I right that hydrogen and helium would leak out cos their molecule size is small enough it diffuses through the material? Or did I dream that?
That's right. We use Helium to leakcheck vacuum and toxic gas systems in work for precisely that reason. (<i>escapes easily</i>)
I guess this is why JBD finds the whole concept of Helium inflated inner tubes so amusing.
On the squeaky voice thing, my brother-in-law managed to render himself unconscious trying that one!