How To: Mix biodiesel fuel

Most videos by Graydon Blair are quite satisfactory, however, this one is incomplete. Graydon spends inordinate amounts of time massing out KOH with a terribly difficult to use scale. Electronic balances are readily available for $15-$20 that are infinitely easier to use. He treats the KOH as if it is the most toxic and dangerous substance one could encounter but cavalierly pours methanol close to his eyes with no protection (his corenea would not appreaciate an methanol bath either!). KOH is essentially lye that is available in stores as a drain opener: it is harmful and one must be careful, but you don't have to be afraid of it. If it gets on your skin, rinse thoroughly. Definitely wear goggles: it does cause very bad damage to the cornea.

The most disappointing part of the video is that he never gets around to actually mixing the methanol/KOH mixture with the oil and running the actual reaction to produce biodiesel. He also mistakenly combines the methanol and KOH in the graduated cylinder which prevents easy stirring of the not completely soluble KOH and difficult transfer of the KOH to the oil. But he neve gets around to showing the actual combination of the KOH/methanol suspension with the oil to demonstrate how to complete the transfer nor to show how the 3 components mix. I do not think there will be complete solution formed and that the reaction is an interfacial one requiring fairly vigourous stirring. I will have to dig around further to find out what happens when the components are actually mixed. Title of video is misleading in this sense.

That said, I really appreciate the information provided by Graydon. He has convinced me that making biodiesel is a gross pain in the neck and not something this backyard chemist is not going to do! (::)

OK, new user here and since we can't edit our comments on this site, I have to explain... Graydon does get around to mixing the three components together in Chapter 2! of the video clip! Makes the video much more satisfying, answers my questions and gives a complete picture! Still would not combine the KOH with methanol in the grad cylinder and stirring would make that step much faster. I am surprised to learn that the KOH is soluble in the methanol.

The methanol/KOH soultion is not soluble in the oil: the change Graydon describes as a "color change" that occurs immediately upon combining is really just the cloudiness of insoluble liquids combined together.

Overall though complete and interesting.