Does Acid dissolve grit lines?

Retroguy

Well-Known Member
#1
If I bring my flats up to a 400 or 600 and dip my blade in will that be enough or will the grit lines still show. Is there a point where the grit lines are dissolved? You know after just typing this, maybe it's a good idea for me to get some scrap steel and do a test on different grit levels and etching solution.
 

Chris Railey

Well-Known Member
#2
In my experience the acid will not erase grit marks significantly. I also think trying to leave a blade in acid long enough to do so would be harmful to the blade. A good etch MAY cover or reduce a small visible abnormality (stray mark etc) but I do not see it working for grit to the point that it will come close to a hand sanded blade which I am assuming you are trying to avoid doing. I once left a bird knife in white vinegar for a week and it ruined the blade completely. If you want a decent finish without hand sanding I would look into media blasting, though I have not done so myself.
 

EdCaffreyMS

Forum Owner - Moderator
#3
If you're referring to a machine/grinder finish to those grits..... no, in fact generally the opposite happens.... scratch marks that were minimally visible before etching will "jump" out, and be 10X more visible.

Now, that being said, a good hand finish is another story.... generally, with 400 grit, unless you hand sand until the paper is so worn out it's slick, the scratches will usually be accentuated by etching. 600 grit will create a smoother finish once etched, provided you pay close attention, and remove ALL of what I call "shadow scratches"....... these are scratches that only become visually evident when you shift the sanded blade around, under a strong light.... and then the surface distortion in the finished surface reveals the "shadow scratches". Whenever I etch any blade, it gets dipped for about a count of 10, withdrawn and examined..... any scratches that need further sanding will be evident. The caution here is to NOT ignore any scratches you see after that initial quick etch.....if left, the etch will only accentuate them.

As a side note to the issue, experience has taught me to steer clear of a buffer for any blade intended to be etched...... trying to buff out scratches usually results in what I call "buffed scratches" look, and even if/when all the heavier scratches are cleaned/cleared, buffing will often result in a "blotchy" look of the etched blade.
 

Retroguy

Well-Known Member
#4
Thanks Ed I understand what you what you
wrote. I think I’m going to do a test run on a 600 grit piece. I will include a 10 second dip and correct the shadow scratches and see what it looks like before I go further. Thanks again
 

Justin Presson

Well-Known Member
#5
It depends I have left a 120 grit belt finish on aebl stainless for 1 hour in ferric and it has taken out the grit scratches. But you have to remeber its eating steel away. I had a small little neck knife I made and ground really thin. I left it in the acid to long and my edge looked like serrated knife it had eaten the edge to the point of paper thin and some of it was gone.
 

C Craft

Well-Known Member
#6
Ed, did a good job of explaining.

You have to think of the use of an acid this way. If the scratch is deep, both that scratch and the field of that blades steel are being eat away at the same rate. The scratch is going to stand out more because the acid eats at the sides and the bottom of that scratch. Thus making it stand out even more.
A fine scratch, if you stop the process at the exact right moment, it may not show because the acid ate away at the surrounding metal and you stopped the process before the acid got a chance to deepen the depth of the scratch. Hitting that right moment to stop the process is a very hard to predict process!

Acid is used in many forms to accentuate Damascus or a hamon because the process of eating at the material to make the good attributes of the metal stand out. Left to long it goes beyond accentuating the blade to destroying it!! o_O

Don't ask how I know that one!! I learned the hard way if a little soak in an etchant is good, then a long soaking for a long period is, an oh $^&t moment!!! :eek::mad: There is another one for the scrap bucket!!
 

Entropy762

Well-Known Member
#7
I have a blade of 1095 that has a hamon. After etching it's pretty clear that I didn't spend a lot of time hand sanding. This was my first time using clay. I etched in warm vinigar and lemon juice. The etching enhanced the scratches from amateur hour blade finishing.


Jacob
 

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Ty Adams

KNIFE MAKER
#8
I have a blade of 1095 that has a hamon. After etching it's pretty clear that I didn't spend a lot of time hand sanding. This was my first time using clay. I etched in warm vinigar and lemon juice. The etching enhanced the scratches from amateur hour blade finishing.


Jacob
That might not all be from scratches left from sanding. It looks like some contamination with spots. How are you cleaning off your blades?
 

Entropy762

Well-Known Member
#9
Ty, I use rubbing alcohol for cleaning. That knife still needs some clean up from the epoxy for the scales. The scratches are defiantly there.

Jacob
 
#10
Next time you try a hamon wash the knife in the sink with soapy water before etching. I wash with soapy, and while rinsing don't touch the blade. Don't dry it or wipe the blade down, just go straight into what ever you use to etch the knife. There is less chance of contamination that way.
 
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