Re: i'm looking for a simple substance that dissolves well in water



darluzo wrote:
>
> Salt is a pretty firm crystal, it doesn't dissolve quickly enough. I
> haven't tried grinding it into powder, that would probably make it
> dissolve instantaneously. The problem is that, to be able to model
> shapes from salt i think i have to moist it first, then it just hardens
> into a formation and dissolves very slowly.
>
> I thought about mixing salt with something that would help the firm
> formation dissolve faster. I don't know, i think hydrogenperoxide
> should dissolve well. Do you think mixing the salt with it's solution
> when building the model would do any good?
>
> I can't use ice because the model has to be lasting.
> By dry ice do you mean carbondioxide?
>
> -- ice with entrapped air would be white and disappear faster --
> What are the simplest ways of making foam like stuff

Mix powdered NaCl table salt that is insoluble in acetone with
powdered NaI that *is* soluble in acetone (gonna have hyroscopic
problems, but what the Hell) and high pressure consolidate or extrude
a solid block. You now have an interpenetrating composite of two
bonded lattices. Carve. Leach with acetone. This leaves an
exceptionally porous yet structurally robust NaCl skeleton that will
rapidly dissolve in water. You vary the amount of NaCl vs. NaI to
control the amount of porosity. You vary the particle size (e.g.,
ball milling) to control the size of porosity.

NaCl, NaBr, and NaI flow like molasses under high pressures otainable
with unremarkable hydraulic presses.

Conceivably one could substitute a combo of *dry* 1:2 mole-mole citric
acid and sodium bicarbonate for the NaI, mix with NaCl, then high
pressure consolidate the NaCl. Carve. When the finished product hits
water it will fizz and disintegrate. Ditto instead adding Pop Rocks,
though that will be pricey unless you can source bulk stuff.

Umpolung! Minimal sugar plus NaI, heat to modest temp to sinter the
sugar, carve, leach the NaI with organic solvent. You now have a
porous sugar form. Ditto the fizzies, too.

Uncle Al would also add a few ppm of sodium fluorescein (uranine) or
other water-soluble fluorescent dye. Give the mob a show before and
after.

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz.pdf
.