I have been busier than a one legged man in a fanny kicking contest lately with real world contract work and have not had any time to work on rifles and the other fun projects. However, I have been interested for quite some time in better ways to permanently stain and color organic materials and have always been interested in the chemistry behind the visual effect. I recently purchased a copy of Bill Knight and Bill Mende's excellent book on "Staining and Finishing for Muzzleloading Gun Builders" and the two "Bills" have been very gracious in their help answering some of my questions.
Just to keep my hands busy for a few minutes each evening, I have been carving the front end of a couple of scrap horns. In the past, if the throat needed staining, I have used leather and Rit dyes or silver nitrate with varying degrees of success. In the following photo of a group of my past horns, some had a naturally black tip, but most were stained by the above methods. They look fine, but the dye is not very durable.
In the next two pictures, the throats of these horns were painted with silver nitrate and exposed to bright sunlight for a day or two. On human skin, this produces a very purplish black, very permanent stain. On horn, it is more on the purple side than black and, if you add a second application, the color actually gets lighter. So these were stained as dark as they would go with the silver nitrate and then evened up and darkened with dark brown leather dye. But, over time, they have had to be retouched as the dye wears off easily at the high spots. (Of course, you can just leave this alone and enjoy the worn look, but I am experimenting with staining here.)
The next two pictures show the latest horn throat experiment done on a scrap horn in a two step process with iron nitrate (prepared by slow dissolution of iron in diluted nitric acid) followed by gallic acid. Unfortunately, I did not think to take pictures along the way, but I will do so in the next experimental run. The tip of this horn was roughly the same color as the body of the horn when I started. To summarize the coloring process, I carved the throat area and polished it to about a 400 grit finish. The iron nitrate was then painted on the slightly off white natural surface and allowed a day to dry. Heat was applied, with a hot air gun, and the throat turned a pleasing, translucent amber (much like honey). The tip can easily be left this way with a very pleasing effect. However, I applied a second coat and heat treatment, but no further darkening occurred. After a few days of sitting on my bench, I dissolved a little gallic acid (solid powder) in warm water and painted it on the throat. Immediately, as I was applying the gallic acid, the horn turned this color black. If scraping some of the black off from around the engrailed edge is any indication, this coloring is very durable as it took considerable effort to remove it with a sharp scraper. Based on what I read in another horn post, I thought some of you might be interested in this coloring process. And again, I would like to thank Bill Knight and Bill Mende for their writings and their advice on the preparation and used of 18th century stains and finishes.
(P.S. The white tip on the horn below is an applied antler turning.....another experiment.)
