Since the post shows that this is your first experience with damascus, I'll give you and others, like Mike, the etchant advise.
Use ferric chloride, which can be found at Radio Shack as printed circuit board etchant ( PCB etchant). It can be bought on ebay,etc. in the dry powder form, and mixed yourself. Use 5 pounds of powder to one gallon of water to make the etching solution. Do this outside, and stand up wind of the bottle. Add the powder slowly, and don't breath the gas that it gives off. It will get hot from the exothermic reaction, but all will be fine once it is dissolved and cooled off. If using the bottled stuff from Radio Shack or other place, dilute it 3 parts water to one part FC solution.
To etch with FC, make an etching tank from a length of 3-4" PVC pipe. Solvent weld a PVC closed flange on the bottom ( makes a steady base), and slip a PVC cap on for a lid ( don't glue the cap on). This will hold the solution safely and is ready to use all the time.If using another type of plastic container to do the etching, when done etching, pour it off from any sludge in the bottom, and cap it tightly in the storage bottle.The solution can be re-used many times and lasts most people for years. On some etching jobs, you may want to dilute some of the etchant even more for a very slow etch. Up to 15:1 is not unusual.
Etching can be done on mounted blades, but that is a big problem. It is always best to etch the bare blades before any mounting work is done in the beginning. Do etching outside if possible, or in the workshop/garage with good ventillation. The stuff stains anything it drips on, and the little lady will not think highly of her floor, sink, and counters having big orange stains. It stains your hands,too, so wear rubber gloves.
To etch, sand the blade to at least 400 grit, going as high as you wish. Clean the blade with soap and water, scrubbing well with a Scotch Brite pad.Rinse well in hot running water. Try and not touch the blade surface ( hold the tang) after cleaning. Use a piece of iron or steel wire to hang the blade in the tank. Try to hang it in the center. You want the etching to be even. The bubbles that form ( you may not see them, but they are there) will run up the surfaces and create funny marks, so move the blade around ( agitate gently) every minute or so. You can also just hold the wire in you hand ( longer wire) and slowly move the blade all the time. After about one minute, take the blade out and rinse it off with a hose, or in the work sink. Look at the pattern, and see if there are any problem areas that are not etching right. This can be from that area not being layered or patterned right, dirt, oil, or some other resist that is preventing the FC from eating the steel. If there is a problem, rinse again, and scrub the blade with a clean Scotch Brite pad. Repeat the first etch and check again. Once all seems to be going fine, allow the blade to etch for the needed time. Take it out every two to five minutes and scrub the black stuff off, rinse, and return it to the tank. After a while, from as short as five minutes to as long as thirty. The blade will look well etched...a bit more than you want. That is where to take it out. You will be sanding the surface and the etching will be reduced. Take the blade and rinse it well. Place it in a pot of boiling water for 10 minutes. This helps set the black better. Take it out and scrub well with soap and water until it looks good. Now, scrub with TSP, or spray with a good amount of windex ( or use ammonia) and scrub again. This neutralizes the FC, and prevents rust from creeping up from the layers to haunt you later. You can always etch some more, if needed, but sanding down a too deep etch removes some of the blade surface, so try to sneak upon the perfect etch.
Re-sand the clean blade gently, to make the high areas brighter, and leaving the lower areas dark.Use a hard backing block for your paper to get the maxumum effect. You may have to give the blade a quick 30 second etch a couple of times to darken some areas. Remember to rinse well and neutralize the FC with a heavy spritz of windex.
Once the sanding is done.......Don't Buff the Blade on the Buffer. Buffing can smear the pattern and make it look bad. It is best to finish by hand to high grit and get the shine you want that way. Once done, lightly oil the blade to prevent rust. Damascus blades should be stored out of the sheath ( all blades should be stored out of the sheath) and oiled or protected with Renaissance wax or such.
There are a lot of things you can achieve with etching. Even mono-steels can be dramatically changed by etching them. Wrought iron shows its pattern after etching. Short etches simply show the pattern, but don't change the surface. Long etches make the blade have a topographic surface. Play with some scrap pieces to see the effects of different dilutions and longer and shorter etches. Smetimes a final buff by hand with Flitz looks great, sometimes not...experiment.
Final note, don't use the same FC to etch mokume' gane or any copper/brass fittings or it may put a funny copper color on your knife blade.
Stacy
