)<br /><br />See the info on foam here:<br /><br /> http://www.uscomposites.com/foam.htmlIt refers to the weight per cubic foot if it is mixed and freely blows under ideal/perfect conditions without being confined.<br /><br />They do this by controlling the size of the bubbles it will make. In its liquid state, it will weigh almost the same by volume no matter which density it is made to be when it 'blows'. <br /><br /><br />Other variables you'll see is that being in a cold situatiuon will cause it to blow less, and being in a highly heated place will cause it to expand more. <br /><br />Also, the more you mix at at time will cause it to generate more heat and expand more (bigger bubbles)than the same amount in smaller pours.<br /><br />When I did several pours- usually about a quart or so of each part using about 14 gallons of the stuff (2lb density) for the hydro, I heated the garage up to at least 90. I got some blowing noticably less than 2 lb. per cu. ft. <br /><br />For the floor, that is 2 layers of Al. 1 1/2" apart, I mixed it when it was about 60 degrees and as soon as the pour was made, I started riveting the deck on as fast as I could, confining it somewhat. Those pours came out much denser and stronger than it was really intended to be if it blew freely and I would have had to trim & shave it to get the decking on.
