- Wood Information
Stabilized Wood Information
What is stabilized wood?
Stabilized wood that is to be used for knife handle material is wood that has been impregnated with a chemical stabilizing solution. This stabilized wood can then be worked with normal wood working tools. Cutting, shaping and sanding will be similar to working with a dense hardwood. The purpose of stabilizing wood is to make it more durable and less prone to warping or cracking than natural, untreated wood. The cost of a piece of stabilized wood compared to a natural, untreated piece is usually about $10 more.
The stabilizing process.
Dry wood (preferably lower than 10% moisture content) is placed in a container with the stabilizing solution. It is put under a vacuum and then high pressure to insure that the solution completely penetrates the pieces of wood. After the wood has been completely infused with the stabilizing solution it is heat cured. This curing process turns the liquid stabilizing solution into a solid.
What to expect from stabilized wood
Many knife makers look at using stabilized wood as an insurance policy. Properly stabilized wood is more durable and much less likely to develop problems in the future. Stabilized wood is also easier to get a good finish because the stabilizing process tends to fill some open pores and evens up the hardness of the wood.
Different woods will respond differently to the stabilizing process. Some woods such as Maple, Ash and Box Elder will have a significant weight gain from stabilizing often more than doubling in weight. Other woods such as Redwood and Walnut will have a lesser weight gain and may end up not quite as hard. When stabilized these woods are still much harder and more durable than the natural untreated wood.
Working with Stabilized Wood
Working with stabilized wood is a lot like using natural, non-treated woods. It can be worked using the same tools and abrasives as with natural woods. The stabilizing process will even up the hardness of the wood as well as fill in a portion of the open pores in the wood. This makes the wood easier to sand and get an even finish that will often times show off the grain patterns and figure in the wood better than the results obtained using the same procedures with natural wood.
Not all stabilized woods will be the same hardness. Some types of wood will not attain the same hardness as others. While the hardness and durability are improved by the stabilizing, care should be taken when working with them. Examples would be some Spalted woods, Redwood and Walnut. These are best worked by hand after rough shaping. Power sanding will remove material faster than harder woods so attention is required when working with these.
Care should also be taken when power grinding/sanding stabilized wood to avoid overheating the material. Using sharp abrasives and not applying excessive pressure helps to avoid overheating. Once again, paying attention to what is happening with the wood can help to avoid problems. Overheating can cause warping and cracks much the same as when working with other natural or manmade handle materials. Easiest way to avoid problems is to throw away abrasive belts when they start to become dull and take your time when sanding and shaping.
How to do fills
It is not uncommon to need to do minor fills with stabilized wood. Especially when using burl. Different types of wood may have small voids, bark pockets, open eyes or checks (shallow hairline cracks). Some people choose to leave these unfilled calling it the natural character of that piece. But if you choose to fill them it is a fairly easy process.
Filling checks is very easy. Using thin CA glue run it into the crack and allow it to settle. Then apply a little more so the glue level is slightly above the surface of the wood. While the glue is still wet take a piece of the last used grit sandpaper and sand the area that has the checking. This mixes sanding dust with the glue to fill the check and blend with the surrounding wood. Let this dry and then sand any remaining glue from the surface of the wood. Done correctly small hairline checks will disappear.
Small voids and open eyes are also fairly simple to fill. Small ones can be filled with a couple drops of CA glue. Apply a few drops of glue into the opening. After a few minutes the surface will drop a bit as the glue soaks into the opening. Let that dry and then apply a couple more drops. Repeat until the dry glue level is equal to the surface of the wood. Sand away any dry glue on the surface of the wood.
Larger voids can require just a little bit more effort. Using epoxy mix with sanding dust from the wood and fill the void. A flat toothpick usually works well for getting this mixture down into the void. While this mixture is still wet, poke down into the void with the sharp end of the toothpick to push it down into the opening and to get rid of any air pockets. As the epoxy mix dries it will likely settle below the surface of the wood. In that case you will want to repeat this process until the dry mixture is level with the surface of the wood. Finally sand away any dry epoxy that remains on the surface of the wood.
Bark pockets are fairly common with burl. When stabilized the bark is hardened but will usually have a small open area surrounding the bark pocket. Fill the openings the same way as mentioned for larger voids. But you might want to mix the epoxy with a dark color sanding dust so the area filled blends with the bark instead of the surrounding wood. The epoxy fill also helps to secure the bark portion to the surrounding wood.
After your fills are completed you are ready to finish your wood.
How to finish stabilized wood
In the early days of wood stabilizing there were only a few different types of wood being stabilized. These were light colored, small pore, non-oily woods. Stabilizing companies would say all you needed to do was sand and buff, no finish required. While this process can give a reasonably good finish to the stabilized wood, you can finish it to look a lot better utilizing slightly different processes.
There is not one process that will give the absolute best finish with all stabilized woods so I am going to list a few methods to accomplish a good finish. Then you will have some ideas how to adapt your methods of finishing for the best results when finishing stabilized wood.
The very easiest stabilized woods to finish will be the light colored woods with very small pores and fine grain. A good example would be Maple. The quick and easy way is to shape and sand your handle to a minimum of 1000 grit. You can go finer but if you stop at a lesser grit you are not obtaining the full potential of the wood. Especially with figured woods. Usually the finer you sand the wood the more defined the grain patterns become. Think of it like focusing a picture. The lower grits can look a bit out of focus while the finer grits bring the picture into focus with a crisp, clear image.
This first method is easy and works well on most woods. After you have sanded as fine as you are going to, then blow off any dust with compressed air. Then using an oil blend like Danish oil or Tru-Oil apply a light coat of oil rubbing it in with your fingertip. Wipe off any excess with a soft rag like an old t-shirt and let it dry. Repeat until you like the way the wood looks. The reason to use an oil blend is that it will fill very small pores with a finish that dries hard, giving a smoother more even surface. This method tends to make the colors more vibrant and adds depth to the figure in the wood. After the final coat has dried apply a paste wax over the dry handle followed by hand buffing with a soft cloth.
Medium grained woods such as Koa, Mango, Silky Oak and Sycamore can be finished the same way as the finer grained woods. But they might still have some open pores. If you want to eliminate the open pores you can get a smooth surface using the following methods.
Wet sanding is a method used by high end gun stock makers that also works well on knife handle material. This method works well on medium and coarse grain woods. The idea behind this method is to develop a slurry of the oil blend and sanded wood that will fill the open pores. Letting the surface dry between several wet sanded coats, eventually ends up with a smooth surface and no open pores.
After you have sanded your handle material to at least 400 grit you are ready to start wet sanding. Using an oil blend such as Danish Oil or Tru-Oil, apply a liberal coat to your handle material. While the oil is still wet sand the wood by hand using a wet or dry sandpaper. This will begin to form a slurry as the oil mixes with the wood that is sanded away. After you have sanded all surfaces let the slurry dry in place on the wood.
After it is completely dry sand away the dried slurry until you reach the surface of the wood. This removes the dried finish that is on the surface while leaving the dried slurry in the pores of the wood.
Next using the oil blend repeat the wet sanding step. After it is dry once again sand away the surface finish. Repeat these steps until the surface is smooth and does not show any open pores.
Then finish sanding with finer grits followed by a light coat of the oil blend you are using. After that is dry apply a paste wax and hand buff with a soft cloth. This method creates a smooth surface that will refract the light in a manner that keeps the colors vivid as well as adding depth to the figure in the wood. Hand buffing allows the figure to maintain its chatoyance, flash and movement that gives the impression that something made of light is moving beneath the surface of the wood.
This method involves more work than other methods but the dramatic results are more than worth the extra effort. If it is more important to you to do the best quality work you can instead of doing things as fast as you can, then you should at least try this method.
CA glue can also be used to accomplish a finish similar to that achieved by wet sanding. I would suggest using one of the odorless varieties. After you have finished sanding the wood, blow off any excess dust. Then apply a coat of CA glue to the surfaces of the wood. Allow the glue to dry completely. Then sand away all the glue from the surface. Repeat the glue followed by sanding until you have a smooth surface with no open pores. Finally apply a paste wax and hand buff with a soft cloth.
There can be variations on these methods. After a little experimenting you will probably develop your own method that works out best for you. The final goal is making the wood you use look the absolute best by bringing out the full potential.
Power Buffing - Unless you get it just right, power buffing can burnish the wood eliminating a lot of the flash and movement in the figure. Some woods will take on a smeared, muddy look when power buffed. Coarser grained wood with larger pores tends to get clogged with buffing compound. My opinion is that you can get a better look by hand buffing and it is a lot safer too.
Maintaining the finish of stabilized wood.
Stabilized wood will keep a good finish much longer than natural non stabilized wood. But over time you might want to freshen it up a bit or maybe you will need to repair some scrapes or scratches.
If there is no damage to the surface you can usually brighten things up just by applying a couple coats of paste wax followed by hand buffing with a soft cloth. Much like polishing a pair of leather shoes.
If it needs a bit more than the simple waxing you can rub down the wood with extra fine steel wool to remove any surface gunk. Then apply a couple coats of an oil blend and allow it to dry. Finish with paste wax and hand buff with a soft cloth. This method works out well with kitchen knives and others that see a lot of use.
If the surface has scrapes, scratches or other surface damage you will want to re-sand with a fine grit sand paper. After you have sanded away the surface damage follow up with a couple coats of the oil blend followed by paste wax and hand buff.