Last weekend I etched some Alabama Damascus and put a handle on it. This was my first time trying to etch damascus. I now have some surface rust on one side of the blade. The process I used was to mix the Radio Shack Ferric Chloride with water in a 50/50 mixture. I used acetone to clean the knife and then etched the blade for 5 minutes. I cleaned the blade using windex while scrubbing with a tooth brush. After cleaning I dried off the knife and used WD40 to oil it down. Later I used 1500 grit sandpaper to light sand the blade to bring out the contrast and re-oiled. Put blue tape on and then used standard techniques to put scales on. Today we had sun for the first time in weeks and took the blade out side to see how she looked and that is where I noticed some brown spots which I assume was surface rust. These are not deep pits.
So my question is what did I do wrong. I have another knife to etch so I want to get the forums advice here before I move forward. Also I could use some advice on what to do with my finished knife and how to address it without me further screwing things up. I do not want to remove the handle as it is African Blackwood Burl and it looks great.
Thanks in advance,
Scott
Hi Scott, I know you have heard folks say they use WD-40 as a lube, but it's not a good oil! It's made to simply displace water, which means it will keep the blade protected from moisture, but only as long as it's not dried out, which it does faster than most think. After my etching is done I will soak a blade in Mobil One over night, then wipe it down the next day, you won't find anything much better than that for soaking into the blade and protecting it. You most likely wiped the blade down good before taping it too and I imagine and that in itself probably stripped any protection from corrosion you had for the blade as well. did you get much depth of etch with a 5 minute soak? Even at 50/50 cut etchant it doesn't seem like it would. Most damascus etch's better with a 3 to 1 mix and a longer soak time. I do use WD-40 at times when I use 1500 grit paper to clean the oxides from the damascus after etching, but then I'll clean the blade of everything and do the Mobil One soak. Hope this helps. Those brown spots should clean up with the 1500 grit lightly polish and wont affect your etch if it's deep enough.
Our best damascus etchant (FeCl) is also a tougher one to neutralize than folks may first think because it leads to corrosion from two fronts. So it is not just matter of neutralizing the acid with an appropriate base, like you would with other acids. Because it is acidic it must be neutralized with a base- sodium bicarbonate, ammonia etc… or the steel will rust. But since it is derived from chloride even after this has been dealt with you can still have chlorine atoms which really react with metals. This is why a simple dip or rinse with a base is not enough, you need to really clean the surface to eliminate those residual Cl atoms.
My usual neutralization involves heavy rinses combined with soaks in ammonia based cleaners and tri-sodium phosphate; a heavy application of both bases and cleansers, followed by plenty of rinsing.
"One test is worth 1000 'expert' opinions" Riehle Testing Machines Co.
Thank you Wes and Kevin. The first time I etched the blade I was using the FeCl straight and I had hand sanded to 600 grit. After 30 and 45 minutes I realized I was not getting a good etch. Read some more on here and called a knife maker I know. He told me to resand at 400 grit as 600 was to fine and dilute the FeCl 50/50. He said I did not need to leave it in as long as I did. He will etch for 5 minutes so that is what I tried. Etch came out great but I did have to lightly sand with 1500 grit to bring up the detail.
Wes, yes I did wipe the knife to put the tape on as I thought it would still protect it. The Mobile One sounds interesting. What do you use to clean that off? Soak in Acetone?
Kevin I believe that Windex is an ammonia based cleaner. Where do you get the tri-sodium phosphate from? Do you oil after cleaning? I have also heard that bees wax is good to use.
Scott
Scott, The Mobil One can be wiped of with paper towel, or cleaned with acetone if it's going to be soldered or epoxied on. I will usually sand to 600 or even 1000 grit as 400 will often have the etchant showing etched scratches on my blades. I do like to protect my blades with a good paste wax also. There are a lot of different ones used and everyone has a preference, mine is simply Johnsons Paste wax. Like Kevin, I will neutralize the etchant with windex, baking soda, and a soak in the tri-sodium phosphate. I find mine at the hardware store and the lumber store in the cleaning supplies. Be sure to wear rubber gloves with this stuff as it is strong and harsh on the skin.
Thanks Wes. Headed to the hardware store today.
Scott,
I can relate to your post etching rust as we've all had it at some time. As Kevin has said, Ferric Chloride or FeCl is sometimes difficult to neutralize. It isn't a typical acid but more of a corrosive salt.
Something that has helped me is after I have applied a generous application of Windex and wiped clean, is to apply some dish detergent (Dawn) and scrub the blade vigorously between two fingers and rinse thoroughly. This seems to aid in the rinse and removal of the FeCl.
Once you are confident of neutralizing & removing all FeCl, I usually will apply a coat of car wax (Mother's Carnuba Wax) to protect the blade from moisture. [Wes has recommended Johnson's Paste Wax which is another excellent choice.] Wax will adhere to the steel better than an oil and does a very nice job of protecting it from moisture.
All my best,
Gary
Thanks Gary. I use renaissance wax which I typically use once i finish a knife. Guess I should try that next time. I never used WD40 before and probably will not again. I found another knife today that had discolored after I etched my markers mark on that I used WD40. I caught this one before I put the handle on so I could re-sand.
