Companies that make paint balls, the kind shot out of an air-gun at 
other people, form and cut half-spheres out of sheets of polyethylene. 
These half-spheres are then heat-welded together. This all happens 
faster than the eye can see, of course.
I'm not so sure that "blowing bubbles" would be the best method of 
producing those plastic bubbles.
Another method may be extruding a continuous cylinder and cutting and 
fusing the end of the cylinder into appropriate lengths. These envelopes 
of plastic could then be loaded into a vacuum chamber - the air inside 
would expand creating a sphere

The whole process of recycling plastic is complicated. The plastic has 
to be washed several times, chopped up, heated, extruded into pellets, 
mixed with virgin plastic, and used in whatever process you want 
thereafter. It may be more beneficial to buy already-pelleted recycled 
plastic.

Other thoughts:
Concrete containing expanded polystyrene (styrofoam) is already fairly 
common.
Maybe you could just add some baking soda to your concrete? ;-)
--
Martin K

Gus S Calabrese wrote:
> I want to make a machine that recycles plastic,  grinds it up, heats it
> and blows very thin wall bubbles to mix with concrete.
> The advice I am looking for is .....
> #1  What plastics are suitable
> #2  suggestions on best size for bubbles
> #3  Has anyone ever worked with a technology like this and if so,  
> what happened ?
>
> Gus S Calabrese
> 4337 Raleigh Street
> Denver, CO
> 720 222 1309     303 908 7716 cell
> adding "spam2006" bypasses my spam blocker.  Please place in the text  
> or at the END of the subject line.
> ( i am hard to reach by phone )
>
>
>   

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