ferric chloride strength

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BUILTnotBought#B&B

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Mar 19, 2023
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so im just beginning to make damascus knifes and im using ferric chloride to etch them but im having a hard time figuring out if my solition is too strong or if im leaving it in there too long..... does anyone have any tips on how to tell if my solution is too strong or too week?
 
I used to etch with ferric chloride, the Radio Shack brand, but found it’s 10 times faster with a 9volt battery with leads, salt, water and a q tip.
 
okay i was running it betweek 15-18 min... i keep a stop watch running as i etch it... im using loudwolf etchant the bottle says 99.9 pure regent im usings a 50/50 min
 
slim tissue said:
You can watch the contrast start to form & darken over time. When it's at a contrast i like it gets put in baking soda & water.
Are you also agitating the blade while it's in there?
Click to expand...

not much just to the point of shaking it back in forth a few times ever dunk and will beush it a lil bit with a small brush wen its inside.... the thing i notice tho is literally after a min or 2 its dark covered completely in smut should that be happening?
 
BUILTnotBought#B&B said:
not much just to the point of shaking it back in forth a few times ever dunk and will beush it a lil bit with a small brush wen its inside.... the thing i notice tho is literally after a min or 2 its dark covered completely in smut should that be happening?
Click to expand...
No. That should not be happening
 
Your FC is too strong. Dilute the stock solution 3:1 or 4:1 with water for etching damascus. You start with a 42°Baume stock solution (the standard solution). That needs to be diluted. For some things, like a hamon, the FC is diluted 15:1 with water.

How long to etch???? It can take from 30 seconds to just check the pattern to 30 minutes to get a deep etch on some steels. Most etch to give a reasonable topography (peaks and valleys) in 5 to 15 minutes. Room temperature is fine.

Clean the blade thoroughly with dish soap and running hot water. Don't touch it on the blade area after cleaning.
Place the knife in the FC and let sit for a few minutes. Take out and wipe the black crud off with a clean paper towel. Rinse off and put back in the FC. Repeat the wipe off every 3-5 minutes as needed. The crud covers the blade and stops or slows down the etch.

While the black color looks cool, it is just the surface and will mostly wipe off. Etching is about creating high and low spots in damascus or getting a patina on monosteels. It won't make a blade black. Also, the surface color is only a few millionths of an inch thick and will wipe or rub off easily. The normal result after cleaning is a darker gray tone/patina.

When done with your etch scrub the blade in running water with a stiff brush (most of the black will come off), then scrub with baking soda and hot water. A neutralizing wash with TSP or ammonia cleaner will help prevent future rust spots showing up.

Some folks take the blade from the FC when done and rinse it off but leave the black crud on and then boil it in water for about 30 minutes. This helps remove any Fc in cracks and some say it helps the black etch stay on better. I don't do that and really don't see a reason besides getting the last FC out of the cracks. I would still give it a good spray with TSP when done just to be sure all FC is gone. Those who do this procedure may chime in with their comments on it.
 
After all that a light hand sanding with 2,000 grit sandpaper too.
 
Stacy E. Apelt - Bladesmith said:
Your FC is too strong. Dilute the stock solution 3:1 or 4:1 with water for etching damascus. You start with a 42°Baume stock solution (the standard solution). That needs to be diluted. For some things, like a hamon, the FC is diluted 15:1 with water.

How long to etch???? It can take from 30 seconds to just check the pattern to 30 minutes to get a deep etch on some steels. Most etch to give a reasonable topography (peaks and valleys) in 5 to 15 minutes. Room temperature is fine.

Clean the blade thoroughly with dish soap and running hot water. Don't touch it on the blade area after cleaning.
Place the knife in the FC and let sit for a few minutes. Take out and wipe the black crud off with a clean paper towel. Rinse off and put back in the FC. Repeat the wipe off every 3-5 minutes as needed. The crud covers the blade and stops or slows down the etch.

While the black color looks cool, it is just the surface and will mostly wipe off. Etching is about creating high and low spots in damascus or getting a patina on monosteels. It won't make a blade black. Also, the surface color is only a few millionths of an inch thick and will wipe or rub off easily. The normal result after cleaning is a darker gray tone/patina.

When done with your etch scrub the blade in running water with a stiff brush (most of the black will come off), then scrub with baking soda and hot water. A neutralizing wash with TSP or ammonia cleaner will help prevent future rust spots showing up.

Some folks take the blade from the FC when done and rinse it off but leave the black crud on and then boil it in water for about 30 minutes. This helps remove any Fc in cracks and some say it helps the black etch stay on better. I don't do that and really don't see a reason besides getting the last FC out of the cracks. I would still give it a good spray with TSP when done just to be sure all FC is gone. Those who do this procedure may chime in with their comments on it.
Click to expand...


orite awsome! i appreciate the advice.... and gonna try diluting it 3-1 or 4-1.... i started off with a 99.9 pure powder and only diluted it a 2-1 mix
 
No, just wipe it off between dunks. Once done and neutralized, give it a light sanding with very high grit paper to brighten the high spots.
 
Here is my recipe for mixing FC. I was a chemist back in the 1970's.

Here is my standard recipe:

Mix outdoors and don't breath the fumes when it is dissolving. Wearing gloves and a face shield, is a good practice. Add the powder to the water .... never the other way around. Add slowly.

FC should be mixed to make a 42 Baume stock solution. You add one pound of crystals to 18 ounces of water to get this strength - one pound to one pint is close enough. Delbert Ealy, who knows a lot about etching solutions, suggests you let it sit for a couple days before use. Dilute the working solution from this stock . Three parts water to one part stock is what I use ( that is the same as Del's one pound to one gallon in his recipe).
If you are just making up one gallon, skip the stock solution. If making up a larger batch, one gallon of stock solution is easier to store than four gallons of working solution. For one gallon of stock, mix four pounds FC powder with a gallon of water.

The liquid will get warm/hot as you mix it, so add the powder slowly to the liquid in a large heavy plastic drywall type bucket. Add slowly, stir gently, keeping upwind. A fan running behind you to push the chlorine vapors away is a good idea. When the solution has completely mixed, cover loosely and let cool off before transferring into a heavy duty plastic storage bottle. Use a funnel and pour slowly. Pour over dirt or grass, as FC will stain concrete and can ruin deck boards (don't ask me how I know this :) )
 
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