The folks at Aerogel.org are serious about it: The “Make” section of their exhaustive “open source aerogel” site will teach you how to make high-quality monolithic aerogel the way the pros do it, from building your our own supercritical drying apparatus (“manuclave” is their neologism), to mixing up the wet ingredients, to actually performing the supercritical drying operation. It still won’t be easy or cheap, but all the information you need is right there, well organized and clearly explained.

More:

• Homemade Silica Aerogel
• Experiments with aerogel
• Aerogel – 99.8% air, 100% cool