attempt #7

is in the autoclave. It was a triple batch of Alcogels using a modified version of the “Single-Step Base Catalyzed Silica Aerogel” recipe. After washing it 3 times in triple volume Ethyl, the Wash ethyl was at 198 proof, and as it started its current life-cycle at or around 199.75 proof, I thought that was sufficient.

So, of course, after I (carefully) transfer it all into the Autoclave, and spend a few hours closing the ‘Clave (think 4″ Schedule 80 Nominal Pipe, 12″ long, with a cap welded on the butt and the open end threaded. To thread the 3000lb-rated cap on securely enough to keep it from leaking, I use a wooden frame (4’ 4X6 Lumber, 10″ 3/4″ Lag bolts) with a 36″ pipe wrench embedded in it, a 48″ Pipe wrench on the cap, and a 2.5 ton come-along to turn it. Fun!).  Once Sealed, the whole works goes into a 2 foot square metal tub, Styrofoam insulation is “applied” to the outside of the Tub to keep the inside cool, CO2 Inlet & Exhaust are hooked up, and I test the seals with soapy water. This batch’s initial go failed as the CO2 was spewing out where the inlet check valve meets the Autoclave. I disconnect it, and note that I’ve cracked the Check valve in the threads. So I look for a replacement part, and not finding one local, wait for a few days to get it by mail.

With new part in hand, I reassemble the contraption. No leaks, so I add Ice is to the Bath, and after a few hours, I start extracting Ethyl. I get between 1/5 to 1/4 of the ethyl extracted, and I run out of CO2.

OK. I make plans to get CO2 refilled on Saturday, and due to my own laziness and lack of sleep, I take an unexpected nap around noon. My CO2 supplier is open until 2pm on Saturdays. Guess when I woke up? That’s right, 2:35 PM.

So Monday morning, I get up earlier than usual, and I get the CO2 refilled. I drive back to the lab, and hook the tank up. Pressure in the Autoclave is ~500 PSI, Temp is 0.2° C, and there is at least a Litre of Ethyl left in the autoclave. So, this may be another case of “I fubar-ed it”, but it may not, so I go through the motions. Only to realize after 10-15 minutes that I forgot to Teflon wrap the CO2 Tank’s threads. Pressurized CO2 escaping causes cold. lots of cold. I didn’t realize there was so much ambient water vapor in my lab until I saw the Ice grow on the CO2 tank.

Fixed that, and now I need to see how it fared overnight.

Wish me luck!


About Rey d`Tutto

Hey, Y'all, I've been rather ill recently, and that has kinda deprived me of the ability to post regularly. I may or may not ever post regularly again. Thank you for playing.
This entry was posted in Aerogel, For Science!. Bookmark the permalink.

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