Having trouble with an etch

B

buffalo01

Joined
Oct 13, 2016
Messages
333
Hello all, I'm making a knife for a customer and really struggling with an acid etch. I'm using the same process as I did for my first etch for the most part but getting pretty different results.
Knife is sanded to 240 as before
80crv2
Cleaned with rubbing alcohol, also tried Windex with same result
About 15 percent ferric acid in filtered water. (Maybe I used distilled water before but I'm pretty sure I didn't)
I have done at least 4 other knives I can think of with pretty good results. 2 Damascus 1 80crv2, and 2 1084.
The weird part is that after the first fail, I hit it on the grinder again etched again with fresh etching solution and better surface prep, but i still had blotches in the exact same exact places on both sides of the blade, always a white-grey color
Any help will be appreciated, I have searched but still don't understand how the botches are in the same place both times?
Etch https://imgur.com/gallery/TWBU4de
TWBU4de

Sorry for my awkward hands, I'm a quadriplegic and that right hand is a little in the week department
 
It kind of looks like there’s alot of decarb still on it. How was it heat treated?
 
Josh Rider said:
It kind of looks like there’s alot of decarb still on it. How was it heat treated?
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standard Heat to past non magnetic, hold fora a bit over 5 minutes then quenched in canola oil. It did have a bunch but it was all ground off after a 2 hour temper x2 at 375.
Don Hanson III said:
Looks like it needs more grinding. Assuming it got hard.
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It skated like a pro hockey player and was never past luke warm during grinding. I also had to enlarge a pin hole near the blade, it it was definitely hard. Just ask my poor drill bit :( xD
Im going to try a gun blue tomorow instead because I have more experience with it.
 
Did you grind the flats before or after heat treat? I agree with Josh, it looks like decarb to me.
 
Drew Riley said:
Did you grind the flats before or after heat treat? I agree with Josh, it looks like decarb to me.
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Well I will side with yall, after grinding off another failed etch I ended up going with gun blue. It took the blue perfectly so Im assuming the rest of it came off on the last refinish? Question is, (and im still learning here so stay with me) can there still be decarb if the steel is shiny?
 
buffalo01 said:
Well I will side with yall, after grinding off another failed etch I ended up going with gun blue. It took the blue perfectly so Im assuming the rest of it came off on the last refinish? Question is, (and im still learning here so stay with me) can there still be decarb if the steel is shiny?
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There can be decarb if the steel is shiny. Sometimes if you angle the blade in a good light just right, you'll be able to see it very faintly.
 
Besides the possible de card issue. I would add some table salt into your enchant mix. I’ve used just salt in distilled water with great results. Also try a new piece of pad material on the wand.
 
You guys are the best! Ill be more carefull with my grinding next time, Or just hand sand it like a read man XD
 
I can usually tell when I’ve grinded the decarb away when I start throwing sparks again uniformly on the grinder. Sometimes if decarb is deep it’s hard to tell.
 
Josh Rider said:
I can usually tell when I’ve grinded the decarb away when I start throwing sparks again uniformly on the grinder. Sometimes if decarb is deep it’s hard to tell.
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Another question, How big a problem is the decarb? Is the carbon loss a major problem? As I said My knives are certainly getting hard, and seem to perform well enough.
 
I’m afraid I don’t know much about that, many more experienced people on here that will hopefully be able to answer that. I try to spend the least amount of time in the forge or heat treat oven to limit decarb.
 
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