Alan,

On Mon, 14 Aug 2006 16:15:45 +0100, Alan B. Pearce wrote:

> >Other thoughts:
> >Concrete containing expanded polystyrene (styrofoam) 
> >is already fairly common.
> >Maybe you could just add some baking soda to your concrete? ;-)
> 
> Well, I was thinking of ping pong balls ...

Or just lay perforated plastic pipes at the bottom, and pump air in so that it bubbles up into the setting concrete - it works with Aero chocolate!  :-)

Cheers,


Howard Winter
St.Albans, England


-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist