Aerogel — that mixture of air and silica — is one of those materials that seems like a miracle. It is almost not there since the material is 99% air. [NileRed] wanted to make his own and he documented his work in a recent video you can see below.
If you decide to replicate his result, be careful with the tetramethyl orthosilicate. Here’s what he says about it:
And the best part is, that when it’s in your eyes, it gets under the surface, and the particles are way too small to remove. For this reason, you could go permanently blind.
It can also mess up your lungs, so you probably need a vent hood to really work with this. It isn’t cheap, either. The other things you need are easier to handle: methanol, distilled water, and ammonia.
The process involves developing a silica gel and then letting it dry. Sounds easy, but you’ll see in the video that it isn’t as simple as it sounds. [NileRed] made it harder because he wanted to make nice shapes of aerogel even though it is very fragile. The construction of the mold is actually very clever and requires a trip to the dollar store.
Drying the material out requires a lot more methanol to displace water. Then you can remove the methanol leaving the air in the material. Doing that requires CO2 to drive out the methanol and then rapidly convert the liquid CO2 into a gas. A sous vide cooker found a new use in the process.
This was not a quick project. The video is 43 minutes long and we can’t think of where you’d cut anything out, other than the promotion of other videos in the last few minutes.
Given you can buy an aerogel disc or cylinder for around $40, we aren’t sure we are going to rush to replicate this experiment. On the other hand, we were super impressed with the work and it was interesting to see the solutions to the difficult problems.
There are other materials that can form aerogels, including ceramics. [Ben Krasnow] has done a similar video in the past that uses a very similar process, but he didn’t have the clever molds that [NileRed] uses.