I originally wrote this for the "Horn Tips" section of the Honourable Company of Horners "Horn Book" some time ago. It was recently suggested that I post it here. Here is the edited and updated version.
Frequently I’m asked how and why I apply color on a powder horn. The second is the simpler of these two questions to answer. Old horns are often very appealing shades of yellow. At least my eye finds them appealing. While I don’t have any definitive proof, my belief is that most of these various shades of yellow are the result of oxidized oil accumulated through the years. I say most, because I have seen and examined old horns that were obviously colored. The Jacob Mermeseau horn (Photo 1) is a good example. Note that two shades of yellow were used; one as background and the other as a highlight. Tansel horns also show the use of this technique (Photo 2). In addition, some people find white horns too stark in appearance. Basically, if it is historically appropriate or someone asks, I color the horn.
When I am ready to apply color, the very first thing I do is clean the surface to be colored. I use de-natured alcohol, liberally applied until there is no trace of oil remaining. Then I apply a coating of Aqua Fortis with a piece of clean cloth. I set the horn aside to dry for awhile, supporting it with a small screw driver in the spout hole set upright in a vise. This keeps the colored area from touching anything. After a half hour or so, I wipe the horn to make sure that the Aqua Fortis is evenly distributed. You don’t want runs, or thick and thin spots, at least not if you want a uniform shade of yellow. The Aqua Fortis goes on almost clear and gradually turns a faint yellow. I let this set until it is thoroughly dry, then, using a heat gun, I apply heat. I continually rotate the horn, gripping it by the spout, while applying heat. Use a heavy glove as the horn needs to get HOT. How hot? Hot enough so that you won’t be able to comfortably touch it. You will see the color darken as the horn gets hotter. Sometimes this can occur quite abruptly, so don’t get carried away with the heat or you will see blisters and then smoke! On the other hand, don’t be timid. The horn needs to get really hot to bring out the color.
If you don’t think the color is dark enough, let the horn cool to room temperature, then recoat it with Aqua Fortis and apply heat again. It usually doesn’t take more than two applications for me to get the depth of color I want.
Expect variations; each horn is somewhat different from every other one. If the color is a bit too bright, you can tone it down by rubbing the horn with a very dilute solution of potassium permanganate. Using this method I have produced colors from almost orange to a tawny yellow.
To achieve the effect illustrated on the Mermeseau or Tansel horn, after the background color is finished, apply Aqua Fortis with a small brush or piece of wood to the areas to be highlighted. Then heat these areas, repeating the application as many tines as necessary until the desired depth of color is achieved.
There are a variety of methods that others horn workers use today. As only one example, Scott and Kathy Sibley have an excellent written and illustrated presentation of their method in “Recreating the 18th Century Powder Horn”. These other techniques can be just as successful as mine. I like my method as the materials were available in the Colonial period and in my small shop this method doesn’t require any additional space. I also find it quick, easy and controllable, too.
