By Chris Crawford (October, 2001)
PLEASE NOTE: Many of my knifemaking methods have changed since writing this tutorial. To see my latest methods, please check out the DVDs Basic Slipjoints and Intermediate Slipjoints.
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I found a good method for stabilizing and coloring bone in the “Shop Talk” area of BladeForums. This was my first time to try this method, and I was pretty pleased with the results. Here are the steps: 1) Take a glass jar and fill it with wood hardener. 2) Add in the die of your choosing and mix it up well. You can add some acetone if you want to thin the liquid. 3) Use a hair drier and heat the liquid in the jar until it’s warm to the touch. Leave the top partially off as seen in the second photo. 4) When the liquid is good and warm, heat the bone in the microwave for around 25 seconds. 5) Immediately drop the bone into the liquid as soon as it comes out of the microwave. 6) When the bone quits fizzing, screw the top tightly onto the jar. 7) Wait until the jar reaches room temperature and place it in the fridge overnight. 8) Take the pieces out of the liquid, blot them off with a paper towel, and set them out to dry.
I took my bone out after about 12 hours, but I would have liked to bone to have gotten a little darker. Next time I’ll leave it in for about a day. Also, I didn’t have any wood hardener so I used polyurethane. I used leather die as my coloring agent, but I’ve also heard of using food coloring or Rits Die.
While the bone scales are drying, we will turn our attention to cleaning up the blade. Be patient and allow yourself plenty of time for these steps. I start off by clamping a board in the vice and c-clamping the blade to the board. I use leather around the blade to keep it from getting scratched up. Take a piece of brass, or any other flat and hard material, and wrap it with sandpaper. I start off with a 180 grit. Sand the blade back and forth until all of the scratches in the blade go in one direction. Turn the blade around and do the same to the tang area. Flip the blade over and do the same to the other side. Then take the blade out of the vice and sand the areas that you couldn’t get to. When you have all of the scratches going in the same direction, go to a finer grit sandpaper and repeat the process but change the direction you are snading. Keep doing this until you get up to about an 800 grit paper. Be sure to remove all of the scratches from the previous paper before moving on to the next.
If all of the sanding was done correctly, the blade should look similar to the one above. I included a comparison picture showing the blade just after I finished grinding it, and the way it looked after I finished sanding it down. Can you believe the difference? The blade at this point is very hard but very brittle. It needs to be hard so it will keep an edge, but it needs to be softened a little so it’s not so brittle that it breaks. Do this by heating it in the oven for 1 hour at 350 degrees. Take the blade out and let it cool to room temperature. Then put it back in the oven for another hour at 350 degrees. When the blade comes out it should be a golden straw color. You may have to adjust the temperature and time depending on your oven. I use to heat the blade at 400 degrees for an hour and a half twice, but the blades were coming out too dark. You can clean the straw color off the blade with a metal polishing compound or by sanding the blade again with a high grit paper.
The inside of the spring needs to be cleaned up so that it will appear nice and smooth when you look down into the knife. Clamp the spring in the vice and use different grits of sandpaper to work it down smooth. Don’t worry about the outside of the spring at this time because it will be cleaned up after the final dressing of the knife. It’s also important to clean up the sides of the end of the spring, as seen in the second photo. When the knife is in the half opened position, the sides of the end of the spring will show.
I usually glue the bone scales to the knife before I pin them down. Take super glue gel and cover the surface if the liner. The gel helps seal any cracks that may be between the liner and the bone. I put a pin through the bone and the liner to make sure that the bone is lined up. This next part has to be done fast…. Press the bone firmly down to the liner, remove the rod, and wipe the excess glue away. Be sure not to leave your finger, or anything, in place to long or it will be stuck. Trust me on this. I use to use epoxy for this step. Epoxy gives you a longer working time, but it sometimes warps the liners when it dries.
Once everything is dry, you will probably have to drill the holes in the liner again to remove the dried glue. Next, take a cone shaped Dremel bit and countersink all of the holes on the outside of the liners. You will also need to countersink the two small holes on the inside of the liners.