metal or ceramic foam

>
> > The following recent article on (terrestrially-produced) ceramic
> > foam may
> > be of interest.
> >
> > http://www.sciencedaily.com/releases/2001/05/010518082028.htm
> >
> When I was looking through the patent listing on metal foam using a
> chemical reaction to cause gas bubbles to be formed on heating was one
> of the older known methods. I ignored that type of method because the
> reactions seemed to use rather esoteric compounds that would require a
> full chemical industry to create i.e. a lot of chemicals being shipped
> from Earth to the factory. I am looking for methods that only require
> a few light weight tools to be shipped from Earth.
>