On Tue, 26 Feb 2013 19:56:41 -0800, "PrecisionmachinisT"
wrote:


"Ed Huntress" wrote in message
.. .
On Tue, 26 Feb 2013 19:13:08 -0800, "PrecisionmachinisT"
wrote:


"Ed Huntress" wrote in message
news On Tue, 26 Feb 2013 16:34:01 -0800, "PrecisionmachinisT"
wrote:


"Ed Huntress" wrote in message
om...

I had a six-footer from Edmund Scientific.

http://www.scientificsonline.com/pro...r-balloon.html

"Professional Weather Balloon, One 16 Foot Balloon, 100 Cubic Feet
(3072151) $79.95

Ok, but we were talking about tissue-paper hot-air balloons.

I have a funny story about those weather balloons, and my 8th-grade
buddy's hydrogen-generating apparatus, with zinc chips and some kind
of acid, but I'll spare you. g


Aww come on Ed...

--ya probably already told about it once, just that we've both done
forgotten.

I don't think so. Let me just cut to the end, where the newly laid
tile in my friend's basement turned into a puddle of silly putty...go
easy on the zinc, we learned. g


I vaguely recall making rockets using zinc powder and sulphur as a
propellant, of mempry serves me, the usual exoected progagation rate was
something like 900 fps

That was the formula promoted by Scientific American back in the '60s.
They had a chapter on amateur rocketry in _The Amateur Scientist_ and
I remember the formula. They said it was a lot safer than black
powder. I should hope so...


Pretty sure it's no longer being recommended, good mix / packing job
basically becoming a pipe-bomb

There's supposedly something a lot better.

The formula I was talking about was just pieces of zinc spatter in (I
think) hydrohloric acid. We got plenty of hydrogen -- and a
boiled-over beaker of acid. g

--
Ed Huntress