However, we do (or more precisely, will) have the capability to produce beeswax and vegetable oils (e.g., canola or sunflower oil), which we hypothesized we might be able to combine in certain proportions to produce a mixed-lipid substance with a tunable melting point. The first thing we had to do was build something to measure the melting points. Oh boy, a project!
|We wanted to use a spare piece of leftover metal from the 90° electrical conduit punch-out elbows we used for the row cover we built last fall, but the Home Depot spec sheet said the pieces were either cast zinc or galvanized steel. We were a little nervous about heating zinc (it turns out it would have been fine for this application anyway), but when we held the pieces, they sure didn't feel dense enough to be zinc or steel (which have densities of 7.2 and 7.8 g/cm3, respectively). We suspected they might be aluminum, so we converted an empty spice jar into a makeshift graduated cylinder (sort of like a really nerdy MacGyver), then used the old displacement principle to calculate a density of about 2.7 g/cm3--suspiciously close to that of aluminum. No zinc fume worries, and good thermal conductivity--yay, science! (And Home Depot shoppers be warned...)|
|Then we built a little contraption out of scrap wood to turn our aluminum piece and our wood burning tool into a melting point apparatus. She ain't purdy, but she sure is sturdy!|
|We drilled a partial hole in the center of the bottom in which to nest the wood burner, and two holes equidistant from the center: one for a small piece of whatever solid we're melting and one for a thermocouple or thermometer. This setup heats surprisingly quickly, so we had to serve as our own PID controller by plugging in and unplugging the wood burner. It would be way easier to add a potentiometer between the wood burner and the wall outlet (something like this guy did), if we had one on hand and wanted to precisely control the heating rate.|
|The next step is to put a small chunk of the wax or wax/oil mixture in the one hole, hold the thermocouple in the other hole, and heat 'er up! Keep heating until...|
|....the wax melts! We got 142 °F as the melting point for the pure beeswax, which is pretty close to the normal range. The aluminum plate cools down pretty quickly, so we can record the temperature at which it re-solidifies also, and do multiple melts to get an average. (Since we know the approximate melting point from the first melt, we can unplug the wood burner sooner in subsequent replicates to approach the melting point more slowly--maybe even as slow as a real melting point apparatus would!)|
|With the instrument and methodology validated, we can finally pursue our goal of finding a beeswax/oil blend with the melting temperature we want. We mixed up combinations of 80%, 60%, 40%, and 20% beeswax in canola oil (by volume) as our standards.|
|Then we made sure they were good and melted in the microwave. We stirred the melt to mix everything well, then set them outside to freeze. If the air outside is going to be cold, we might as well make use of it!|
|The 20-80% beeswax standards all had a pretty high melting point (e.g., the 20% mix melted at 118 °F), so we added a 5% beeswax mix to the curve. It looked kind of like runny Vaseline, and seemed to cross over to the liquid side around 70 °F. That's lower than the melting temperature of coconut oil (which we measured at 79 °F, compared to an internet value of 77 °F), and is probably too soft for making deodorant. The 20% mix seems like it might be about right.|
|Here's the data all together. The point at the far left (pure canola oil) is from here since the air outside wasn't quite cold enough to freeze it (nor was our freezer, for some reason). Naturally, the curve would look different if other oils were added into the mix, but we'd wager that oils with a similar fatty acid profile to canola oil would give similar results. The line is a fit to the equation shown, which has no physical meaning, as far as we know, but seems to fit the data well. (Hooray for empiricism!) Physical chemistry students: you might be able to publish a paper on the theory behind it.|
Have you mixed beeswax with other oils for your own homestead hygiene? What's your favorite combination? Let us know in the comments section below!