I have not bought any Sodium Silicate for some time, but it used to be
available in drug stores.

It is also used for casting, so a foundry supply may have it in large
quanities. You mix sodium silicate with sand, pack your molds, then
use a thin tube to inject CO2 which causes the sodium silicate to set.
Sodium Silicate is also known as Water Glass.

Another thing you can do with it is put some in a paper cup and
microwave it. It boils and hardens to form a heat resistant foam.


Dan