<html><head></head><body><div style="color:#000; background-color:#fff; font-family:Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:13px"><div id="yui_3_16_0_ym19_1_1497830829254_2526">Hi All,</div><div id="yui_3_16_0_ym19_1_1497830829254_2526">Just been thinking about low cost ways to make foam. I am sure at the end of the day, I will make my foam the standard way, but it is still an interesting subject to explore. I have learned that microspheres are added to many things, even concrete. That got me thinking, if the compressive strength is there, the best product to reinforce the spheres should be the lightest possible material. Polypropylene is very light and has a compressive strength of 6,000 psi. The fun part about Polypropylene is, it can be recycled from bottle lids etc. I don't think it would take to much imagination to build an oven with a mixer inside and a microsphere injection port. Polypropylene has a specific gravity in the neighbourhood of .7g\cc that means a light weight foam can be made with microspheres and no macro spheres. I don't know about the water absorption properties yet.</div><div id="yui_3_16_0_ym19_1_1497830829254_2526">Hank</div></div></body></html>