At what grit can you longer see scratches?

L

Leon Husock

Joined
Jul 17, 2019
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320
Basically, is there a level below mirror finish where you can't see the scratches from sanding a blade, no matter what angle you look at it? Mirror finishes on use knives seem pointless, but it does bug me when I finish a knife and I can see the scratches from sanding it (I usually stop around 1200 grit because I'm impatient).
 
The reason something looks like a mirror is because the scratches are small enough to not interfere with light reflection, however, on the other side, if it isn't a mirror you will see scratches. rhynowet 1200-1500 will look like a mirror in certain light but have visible/frosty/satin sand lines in other light.

The closest thing I have ever gotten to what you are asking was working with hamons, sand to 1200, and do 5-10 light etch cycles (5 seconds) in dilute ferric and use 1500 grit silicon carbide powder in between etches. This leads to a frosty looking blade with almost no lines but also not mirrored.

Also, have you tried hand sanding to 400-800 grit and getting a perfectly uniform satin finish? or is that what you don't like?
 
You should watch the Nick Wheeler hand sanding YouTube video.
Unless you take it all the way to 6000 grit 3M polishing sheets, you can see some scratches in the right light.
Most likely you actually have deeper low grit scratches than you think.
If you truly remove all lower grit scratches and work up to 800 grit finishing in a smooth single direction (no j-hook scratches), then it will look very nice under any light.
 
Skiller1nc said:
The reason something looks like a mirror is because the scratches are small enough to not interfere with light reflection, however, on the other side, if it isn't a mirror you will see scratches. rhynowet 1200-1500 will look like a mirror in certain light but have visible/frosty/satin sand lines in other light.

The closest thing I have ever gotten to what you are asking was working with hamons, sand to 1200, and do 5-10 light etch cycles (5 seconds) in dilute ferric and use 1500 grit silicon carbide powder in between etches. This leads to a frosty looking blade with almost no lines but also not mirrored.

Also, have you tried hand sanding to 400-800 grit and getting a perfectly uniform satin finish? or is that what you don't like?
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I actually posted this after finishing a knife almost exactly the way you described (hamon, a couple quick 5 second dips in ferric, polishing with loose silicon carbide) but I used 2000 grit after a 1200 grit hand sanded finish and I think that's what's bugging me. I'll get some 1500 grit and try again on the next one. Normally on a plain monosteel hand-sanded blade I don't mind being able to see the scratches, it only bugs me when I'm working on a blade with hamon.
 
Leon Husock said:
I actually posted this after finishing a knife almost exactly the way you described (hamon, a couple quick 5 second dips in ferric, polishing with loose silicon carbide) but I used 2000 grit after a 1200 grit hand sanded finish and I think that's what's bugging me. I'll get some 1500 grit and try again on the next one. Normally on a plain monosteel hand-sanded blade I don't mind being able to see the scratches, it only bugs me when I'm working on a blade with hamon.
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I just finished out a hamon at a clean 1200 (after a couple go's) and after a few etch & polish cycles you can see any of the sanding lines
 
Bill DeShivs said:
Why would a mirror finish be pointless?
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Because it's going to get instantly scuffed and scratched up and therefore doesn't seem worth the effort.

AVigil said:
If the point is to have the most corrosion resistant finish on a knife, then it is not "pointless".
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I make mostly kitchen knives so I'm not super concerned about rust or corrosion. Also, if I want the most corrosion-resistant finish I could parkerize it, rust blue it, or a number of other finishes that would offer comparable if not greater protection and be a lot less work.
 
If not seeing scratches and "mirror finishes are pointless
" even though you would not see those scratches, then maybe you should chrome your blades. You will not see those scratches ever again from sanding
 
i have been carrying my mirror finish edc for almost 2 years, it looks great if i wipe off the tape goo. there are some fine whispy scratches depending on what angle you look at it. and trust me, i am not careful with it. at around 5000 grit it gets hard to see the grit lines, its a slightly frosty looking finish.
 
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