
The very first custom piece that I ordered was an Irish skean with a bog oak grip. While the knife itself was not that elaborate, I remember that the bog oak grip was excellent. It had an inky black color that really brought the whole piece together. Ever since that point, I have been drawn to bog oak.
It is hard to find a large enough piece of bog oak that has a really desirable inky blackness to it; so I’ve been experimenting with making my own bog oak in my shop (minus the bog and the thousands of years for the reaction to take place).
Bog woods form when the acidic, iron rich water (iron acetate) of the bog reacts with the tannins in the wood. This reaction stains the fibers of the wood. The color of the staining process ranges from dark brown to inky black.

Around the time of the 16th century, woodworkers utilized this reaction between iron acetate and tannic acid to turn woods black (or darker depending on the type wood). This process is know as ebonizing. Unlike stains which are more of a surface treatment, ebonizing (like bog wood) reacts in the fibers of the woods making the finish much more durable. In other words, the coloring is integral rather than just a surface treatment.
Armed with this information, I set out to make a bog oak haft. The first thing I did was to make the iron acetate. This was a simple process. I washed a pad of 0000 steel wool with soap and water to remove any oils, and I placed it in the mason jar. I then filled the jar to the top with Heinz white vinegar. You need to put a small hole in the lid because the reaction will give off a lot of gas. Which brings me to my next warning: Do not do this in your house because it produces a strong smell. After 5 days, the pad was completely gone. I then put another pad in the solution and left it for 5 more days. 5 days is enough time to give the vinegar an opportunity to dissolve all the steel it can handle. I then filtered the solution using coffee filters to remove any solids.
I put the iron acetate on the shelf and worked on the haft. Once I finished all of the shaping and fitting to the axe head, I sanded the haft to 320 grit. You want to use fresh sand paper and a light touch so you do not burnish the grain closed. This was something that happened on my smaller scale experiments. You want to raise the grain of the wood at least twice and sand again with 320 grit. Once I was finished with the sanding, I deglazed the wood with acetone to remove any oils that may be on the wood surface. I then set up my work table to do the ebonizing process.

The first step in ebonizing the haft was to make the tannic acid solution. After researching tannic acid powders, I contacted the fine people at Shellac.net and they advised me to purchase Quebracho bark powder. Quebracho powder is from the bark of the Quebracho tree and it contains 74-77% tannins which is much higher than other commercially available tannic acid powders. ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………..

This stuff is a massive irritant, so I wore a respirator, nitrile gloves, and eye protection. I began the process of making the solution by putting the correct dry quantity in a mason jar and adding a portion of the required amount of warm distilled water. I put the lid on and shook the jar till the powder was completely dissolved. I then added the concentrate to the rest of the warm distilled water in a glass container. …………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….

Next, I brushed the tannic acid solution on the wood. From previous experiments, I developed a technique of brushing the solution onto the wood liberally for 5-8 minutes, and then allowing the wood to dry on the surface for 20-30 minutes before applying another coat. The goal is to allow the wood to absorb as much of the tannic acid solution as possible. I applied the solution 4-5 times, and let the haft dry completely for several hours. Note: at this point, the solution was not really a nasal irritant, so I removed my respirator. I still wore eye protection and nitrile gloves. …………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….

After several hours, the haft was dry and I started the next step: application of the iron acetate. Over the course of an hour, I applied iron acetate to the haft at 8-10 minute intervals.
At first, there was little reaction, but the following pictures will show the transformation of the wood over an hour. ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
10-15 Minutes

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30 Minutes

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1 hour

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After the last application of iron acetate, I allowed the haft to dry completely. Once the haft was dry, I gave it a final wash in the tannic acid solution, and allowed it to dry overnight.
The next morning, I wiped the haft surface with a clean cloth to remove any dried solution. I then buffed the haft with 0000 steel wool. The staining from the reaction is deep in the wood fibers, so the steel wool did not remove or lighten any of the inky black color. The picture to the left shows what it looked like the next morning after being buffed with the steel wool. …………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….

Actual bog oak has a range of darkness to it: from dark brown to inky black. It is possible to select a wide range of shades by adjusting the amount of iron acetate you allow to soak into the wood and then rinsing it in distilled water once the desired darkness is reach. It is a good idea to stop a shade or two lighter than you want because even with the water rinse, the reaction will still continue in the fibers for a short time. When I made the haft for the recreation of the boy’s burial axe from Dr. Lee Jones’ collection, I wanted a lighter style of bog oak, so I only used a few applications of the iron acetate and rinsed it with distilled water when it was close to what I wanted. The picture on the left shows the final product. ……………………………………………………………………………………………………………………………………………………………………………………………………………………..
One of the big differences with this process and actual bog oak is the depth of the reaction. Actual bog oak has been exposed to the reaction for thousands of years, so the dark finish runs all the way into the center of the wood. I have found that I can achieve a depth of 2-2.5 mm by allowing the solution to soak into the wood with multiple applications. This makes a very durable finish. As I mentioned above, the steel wool did not remove or lighten any of the finish when I buffed the haft. I would, however, like to see if I can get the reaction to go deeper into the wood for the purpose of carving and other decorative elements. I’ve tried some smaller tests in my vacuum chamber with some promising results, and I plan to experiment with larger pieces to figure out the process. More to come in the future!
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Great write up! I have been thinking about doing a very similar process. I was also thinking that putting it in a vacuum chamber similar to how knife handles are stabilized would work well to work the tannins throughout the entire piece. However, the wood would then have to be left to dry for a period of time before working with it.
Thank you! Wonderful article. I am going to try this with red elm for my sons great axe and a set of quarter staffs for my grandsons.