How to Finish Stabilised Knife Handles

Knife handles are a difficult thing to finish. They will be handled, so soft finishes are not viable, and even the highest mirror sheens will dull with use. Knife handles are also often made of extremely dense, oily, figured or stabilised woods. These types of wood offer different finishing issues to other applications.

From shaped to finished, Sanding is the most important part of finishing.

One major factor to remember is to keep the wood cool. Just as steel can overheat and ruin its temper, wood that gets too hot will scorch, crack, check, twist or change in colour. For handles, I highly recommend buying the very cheapest Aluminium Oxide belts and paper and changing them out relatively often, always using fresh, sharp grit to lower the risk of these issues. Its also important to wait a little while sanding to allow the wood to cool down and for the heat to travel within the piece. Uneven heat can also cause cracks and checks. This can also be improved by using a belt grinder at ~25-35% speed. A variable speed grinder makes getting a good finish much easier than going by hand or at a high speed.

A good finish starts with good sanding. After the handle has been shaped, you must remove each layer of scratches carefully and completely before progressing up the grits. Left over scratches will be almost impossible to remove at higher grits.

Assuming handle shaping ended 60-80 grit, The first step should be to go over the handle with an 80-100 grit belt to make sure there aren't any deep scratches from the initial shaping stage. This is also a good time to apply thin CA glue to any small cracks, checks, pin holes, voids and anything else that is vaguely worrying. Run a thin bead over any areas of concern and allow to cure. Depending on the depth of the crack, you may see bubbles as the superglue seeps into the voids. I recommend using multiple thin layers. By filling the crack once or twice with CA, and if glue still seeps down give it 10-15 mins to cure before adding more layers.

Once the handle is at an 100 grit, progress up the grits as normally, common grit steps are grits of roughly 120-150 to 180-240 etc etc Stray grits or pieces of sawdust can scratch the wood or damage the finish. I recommend using strong compressed air to blast away any foreign debris.

Continuing to sand to roughly 320-400 finish. At this point, i recommend stepping down a grit to ~300 and sanding the handle by hand. Examining the piece all over, you may find scratches that had been missed. It will be incredibly difficult to remove these scratches moving forward, and if they can not be easily removed with the 300 paper you may have to re sand the piece at 240 grit and work your way back up.

From here, you can continue jumping up the grits until you reach your desired finish.

Large pored woods like walnut, oak, or wenge can be sanded to ~400-600 grit before no real improvement is made.

Medium pore woods like stabilised Maple, Masur birch and bog oak can be sanded to ~800-1500 grit.

Very fine pore woods like ebony, rosewood, or desert Ironwood can be sanded to 2200-5000 grit.

With a well sanded handle, the next step will usually be buffing. Buffing allows a much glossier finish on wood and can make a huge difference. Many of the same rules from sanding apply to the buffing process.

Buffing

Before you start buffing, I would recommend thoroughly cleaning the handle. Compressed air works well. You must make sure the wood is completely clear of abrasives or leftover sawdust which could get caught in the buffing wheel and damage the finish.

Buffing wheels should be kept covered, if on the machine putting a shower cap over them when not in use works, otherwise being kept in a drawer or bags also work. You can also blow down the wheels with compressed air. Grit and dust that settles on the wheels will be present and mar your materials finish.

Be gentle, soft wheels, low speed and fine compounds.

Use slow speeds if possible, 750-1000 RPM is best. Higher speeds make both damaging the finish and throwing the knife much more likely.

I recommend using a soft, unsewn buffing wheel Dense, spiral sewn buffing wheels can damage the wood and the finish.

Practice good wood buffing technique. Apply a small amount of compound and recharge often.

Avoid overloading the wheel with compound. If you apply too much compound to the buffing wheel, it will become clogged. It will stop effective polishing and deposit a layer of the compound onto the handle, often filling pore or staining part of the wood. Use a buffing rake to clean the wheels as needed

When buffing, take short, slowly moving passes to keep the buffing action even. Buffing a cutting action, just like sanding. If you linger too long in one position, you will carve into the wood slightly, heat up one area and lead to other issues.

If you see scratches, you will NOT be able to buff them out. You will have to return to sanding and remove any scratches by progressing through the grits again, cleaning well with compressed air before returning to the buffer.