What Sajen and Lew said are correct. Here is the procedure that I use.
Steve
Please understand that there are as many methods to etch blades as there are people that do it. Do a search on etching and read what others have to say.
Polish the blade by sanding with some very fine wet-or-dry sandpaper, starting with at least 400grit, then with 600, then as high as you want to go, up to 2000. Use Windex, or any brand window cleaner with ammonia to lubricate the sandpaper, and keep it from loading up. Try not to cut your fingers off.
With each finer grit of sandpaper try to get any scratches out that were left by the previous sanding.
1. Use acetone or denatured alcohol to degrease the blade. Both are flammable, so use good ventilation and follow the safety instructions on the can.
2. Saturate a rag or paper towel with warm vinegar or pineapple juice and rub it onto the blade. Put it on with a fully saturated rag, and wipe it on evenly. Do one side then the other, doing your best to cover the full side of the blade in one pass. Don’t let the solution run down into the grip. I use a plastic trough that is used to wet wallpaper that I bought at the local home improvements store to catch the drips.
3. When satisfied with the pattern, rinse with cold water.
4. Neutralize the acid by rubbing the blade with a thick mixture of baking soda (sodium bicarbonate) and water, or with ammonia, or window cleaner containing ammonia.
5. Rinse the blade in cold water.
6. Dry the blade thoroughly, and oil it well with mineral oil, or whatever you currently use to prevent rust.
An alternative is to use ferric chloride. It works quicker and sometimes brings the pattern out better, but is potentially more dangerous to the blade. (this is the procedure that I use as it is much quicker and often provides more contrast)
1. After polishing as above, use acetone or denatured alcohol to degrease the blade. Both are flammable, so use good ventilation and follow the safety instructions on the can.
2. Mix one part Ferric Chloride, available in the US from Radio Shack as Printed circuit board etchant, with 3 or 4 parts distilled water.
3. Using rubber gloves saturate a rag or paper towel with the solution and rub it onto the blade. Put it on with a fully saturated rag, and wipe it on evenly. Do one side then the other, doing your best to cover the full side of the blade in one pass. Don’t let the solution run down into the grip. I use a plastic trough that is used to wet wallpaper that I bought at the local home improvements store to catch the drips.
4. When satisfied with the pattern, rinse with cold water.
5. Rub the blade with a rag or paper towel saturated with vinegar. I’ve read that this helps to stop the ferric chloride reaction.
6. Rinse with cold water.
7 Neutralize the acid by thoroughly rubbing the blade with ammonia, or window cleaner containing ammonia.
8. Rinse with cold water.
9 Dry the blade thoroughly, and oil it well with mineral oil, or whatever you currently use to prevent rust.