While I really love the idea of following the historic method for making flake white, I have also decided to try and create this pigment using some of the newer methods developed within the last century.
I’ve come to realize that in making flake white I am creating a pigment by taking my ore through a number of small steps. In short, the ore is being slowly dissolved using acetic acid fumes and then reacting with the carbon dioxide released from the manure (the heat helps quicken the process). You can imagine that there is an awful lot of different ways to make this happen beyond the traditional Dutch stack method …
My first help in trying to create a modern process came from Reiner. In an old plumbing book he owns, he found a recipe combining glacial acetic acid with hydrogen peroxide that claimed it would dissolve old plumbing solder. Putting it to the test, it did just that; creating a lot of bubbling and over roughly a day completely liquefied my ore.
Step one complete!
I have been eagerly waiting to see what will happen in my attempt to create flake white and I am happy to write that the process of changing my ore into a carbonate is going well. As you can see the little medallions have quickly begun to develop a white crust!
With all the ingredients prepared all that remained was to setup. Researching some of the different methods used to prepare flake white was very revealing. I think that I will probably try a couple of different methods, but to begin with I figured I’d start at the beginning.
The “Stack Method” is considered the simplest method for creating lead white pigment and it was also the most common until the 1880′s. Basically it consists of three ingredients being brought together: Lead medallions, vinegar and horse manurer (the metal is the base, the vinegar changes the metal into an acetate, and the manurer provides both the heat needed for the process to work and also the carbon dioxide gas which changes the acetate into a carbonate). At least that’s the theory … in fact the Stack Method still isn’t really completely understood and is notorious for less than perfect results with pigment that is pink or yellow, rather than pure white. My favourite science quote about this method described it as being, “happy-go-lucky”. This description alone was reason enough for me to try it!
It made me smile to realise that when I was looking for horse manure I had to choose who I should call. In the end, Henry was good enough to give me a big garbage can full. I’m also using some local apple cider vinegar which is hopefully strong enough. And, in setting up, I had some great helpers too.
At this point everything is setup; I guess we’ll see what happens in a week’s time!
In preparation for turning the galena collected at Dundas into flake white I needed some kind of guinea-pig (I wonder if such a phrase is still politically correct ..?) to test my proposed processes for turning such a metal into an oxide pigment.
I don’t know why it came up in conversation, but my neighbour mentioned that they still use lead in balancing tires; and he also happened to have some such wheel weights in a bucket! So outside, and with a good breeze blowing across my little camp stove, I used my little plumber’s torch to melt down these scraps and then cast them into a few aluminum cups.
The work was quick and without incident. Each little medallion released from the cup by giving it a gentle squeeze and I stacked them in a bucket for use in the next step.
My only real concern at present is that I know this sample will not be pure. Wheel weights are roughly 95% lead, but they also have some tin and antimony mixed in them to produces certain properties. These extra elements might have some unexpected impact on my tests (which I will be on the lookout for). Still, it is good to have something other than my little bit of galena to test my theories!