Well... After the threads regarding where to find foam in the San Francisco Bay Area basically turned up not a lot of options, I finally found some. I went to Bob's Foam Factory in Fremont, CA and they sell the blue stuff. It is in 2'x8' sections that sells for about $26 a section. I bought two sections today and had them cut it in half, so I now have four 2'x4' sections. A little pricy, I suppose...but at least you can get some without making a huge bulk order somewhere or chancing that Home Depot or someone just has some laying around.
Bob's Foam Factory is located at 4055 Pestana Place in Fremont Phone number is (510) 657-2420
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-John
*You are nothing until you have flown a Douglas, Lockheed, Grumman or North American*