Neutralizing Etching Solution

opaul

Well-Known Member
Question. I typically use Windex for neutralizing the ferric chloride when I etch blades. Vegas Forge suggests using baking soda as an alternative on their damascus. On a stainless Damascus the windex didn’t do anything as far as revealing the pattern But I etched again And then used baking soda and the difference was amazing. It was like a sloughing off a layer of film and the pattern showed beautifully.
Do any of you guys use baking soda?
 

Gliden07

Well-Known Member
I use TSP but I'm sure the Baking Soda would work? Curious to hear others response. Following!
 

Kevin R. Cashen

Super Moderator
Baking soda works, but... FeCl has a two part action as far as corrosion. It is a weak acid, but there is the "Cl" part to deal with as well. Once you have neutralized the acid nature with a base you will still have stray Cl atoms present, one of the most corrosive elements around. This is why many folks in the past began to believe that baking soda wouldn't neutralize FeCl. They would simply neutralize the acid and then not fully rinse all traces of Cl. The truth is that just about any base will work, I prefer ammonia, but even more critical is the thorough rinsing. This is why I use a combination TSP and ammonia. TSP is a very powerful cleanser and helps remove all traces of the FeCl, even after it has been neutralized. I take the final etch, rinse liberally with water, spray with an ammonia solution until dripping, rinse again, then dip in a strong tsp solution before the final rinse.

After this, I can leave a damascus blade setting on the bench, next to a 400X carbon steel blade and even in the humid summer months see no rust whatsoever on the damascus, while the carbon steel blade will begin to bloom, and require re-polishing, within a day or two.
 

opaul

Well-Known Member
Baking soda works, but... FeCl has a two part action as far as corrosion. It is a weak acid, but there is the "Cl" part to deal with as well. Once you have neutralized the acid nature with a base you will still have stray Cl atoms present, one of the most corrosive elements around. This is why many folks in the past began to believe that baking soda wouldn't neutralize FeCl. They would simply neutralize the acid and then not fully rinse all traces of Cl. The truth is that just about any base will work, I prefer ammonia, but even more critical is the thorough rinsing. This is why I use a combination TSP and ammonia. TSP is a very powerful cleanser and helps remove all traces of the FeCl, even after it has been neutralized. I take the final etch, rinse liberally with water, spray with an ammonia solution until dripping, rinse again, then dip in a strong tsp solution before the final rinse.

After this, I can leave a damascus blade setting on the bench, next to a 400X carbon steel blade and even in the humid summer months see no rust whatsoever on the damascus, while the carbon steel blade will begin to bloom, and require re-polishing, within a day or two.
Thanks. I appreciate the response. I do rinse generously after neutralizing.
Question. Do you reuse the tsp solution or do you keep it and use it several times. Not trying to be cheap. Just frugal.
 
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EdCaffreyMS

"The Montana Bladesmith"
I have a "tank" of saturated TSP next to my Ferric....... I use it over and over. Generally speaking it will last around a year's worth of blade for me. I also use ammonia as a follow up "rinse"..... then a scrub with #0000 and soapy water. As Kevin said.....the important thing is to neutralize everything that's there from the etchant.
 

Kevin R. Cashen

Super Moderator
Thanks. I appreciate the response. I do rinse generously after neutralizing.
Question. Do you reuse the tsp solution or do you keep it and use it several times. Not trying to be cheap. Just frugal.
I'm probably even cheaper than you on how seldom I switch out my TSP tube.
 
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