Sharpening carving tools is an essential step in carving. A sharp carving tool works better because it slices through the wood easier, making it safer and quicker to use. It, also, leaves a cleaner path behind. A good sharp edge means less effort, which means less force. When less force is needed, more control is possible, making the work safer.
There are many methods of sharpening carving tools from power grinders to wetstones to sandpaper and finally the strop. The most inexpensive method is using a couple of grades of sandpaper and a strop.
Compound Saw
How much sharpening is needed depends on how damaged the edge of the blade is. If damaged or dull, you will need to use a 400 grit sandpaper laid on a flat surface such as the edge of the table. Place the blade edge down and drag it across the wet surface of the paper at an eleven degree angle. One way of finding an approximate eleven degree angle is to use either a nickel or a dime beneath the spine of the blade.
If your carving blade is three quarters of and inch in width or more, lay your blade flat on the sharpening surface and raise the spine of the blade until you can fit the edge of a nickel under it. If it is less than three quarters of an inch, use a dime.
Drag the edge along the wet sandpaper surface until all the nicks are gone and you have a smooth edge. Then do the same thing using a 600 grit wet sandpaper.
Finish by loading your leather (strop) up with your white aluminum oxide to the point that it won't absorb any more compound. You can use some light oil to help create a paste-like consistency. Make sure you wipe your blade clean of any sandpaper residue with a cloth. You don't want to get any grit on your strop. Then drag your knife edge along the strop at the same 11 degree angle, and continue equally on both sides, sharpening until you get a mirrored edge.
You can test the sharp edge by taking your knife and carving across the end grain of a piece of carving wood. You should see a smooth shiny surface and the end grain clearly. If you see a white line in your slice, you have a nick in your edge. You need to go back and start the process over. Once you have the edge you like on your knife, all you should have to do is strop about every fifteen minutes and protect your edge when you're not using your knife.