Mirror polish finish

razormaker

razormaker

Joined
Mar 6, 2015
Messages
99
Hi guys,

I'm sure this question has been asked before and buried somewhere in here. But I'll ask again anyway.

I can not get the mirror finish I am looking for. There are always those little micro scratches in the finish that detract from the look. I am stumped. I belt grind to 1200, polish with red rouge and then white rouge. What is the answer? More grinding, am I missing a belt grit? More pressure or less pressure. Longer polishing or a different rouge?

I am working with 52100 and D2.

I appreciate the help.
 
Not a bladesmith but when I had this issue on my swords it was generally because I had not removed all the scratches from the previous grit.

Another option is you have debris in your equipment that is causing the microscratches. Happened to me when I tried to buff and polish a sword with a paper wheel and using rouge.
 
I don't have any experience really with this, but i recall a different thread asking the same question and he was using the same buffing wheel for the same different rouges. That was his problem. Best of luck.
 
I see a few issues. First, I think you arent getting out all the scratches. I have talked to guys and they say grinding to a really high finish works best with heat treated steel, go through your grits to around 1200, then start going by hand jumping back down to 600-800-1000. When hand sanding, make sure each new grit is sanded 90 degrees to the last marks. Its really easy for belt grinders or hand sanding to hide scratches when you sand in one direction. Lastly on the buffer, red doent cut. Its a polishing rouge for jewelry. I would get some coarse black, then fine and rough white as well as green compound of sharpening and polishing. I have one dedicated felt wheel for nothing but green and one for buffing wood, then two that I clean regulary and use with black, fine white or rough white.

Then again, I hate mirror finish. I like Laurence Segal's saying, nothing looks worse than a mirror blade with a scratch.
 
hellspawn415 said:
I see a few issues. First, I think you arent getting out all the scratches. I have talked to guys and they say grinding to a really high finish works best with heat treated steel, go through your grits to around 1200, then start going by hand jumping back down to 600-800-1000. When hand sanding, make sure each new grit is sanded 90 degrees to the last marks. Its really easy for belt grinders or hand sanding to hide scratches when you sand in one direction. Lastly on the buffer, red doent cut. Its a polishing rouge for jewelry. I would get some coarse black, then fine and rough white as well as green compound of sharpening and polishing. I have one dedicated felt wheel for nothing but green and one for buffing wood, then two that I clean regulary and use with black, fine white or rough white.

Then again, I hate mirror finish. I like Laurence Segal's saying, nothing looks worse than a mirror blade with a scratch.
Click to expand...

Great idea on the hand sanding and going 90 degrees. I have black rouge, I'll try it instead of the red. I am leery of mixing colors on the buffing wheel. Green and black on the same wheel? What do you think?
 
Before buffing you need to sand up to at least 2000 grit, and don't mix buffing compounds on the same buffing wheel. A separate wheel for each compound.
 
Are you flat or hollow grinding? What steel?When I mirror finish on a hollow grind I do it all on the grinder up to 2500,(a30,a16,a6 trizact) green compound, then pink scratchless. If flat, 600, 800, 1000, 1200, 1500, 2000, then green and pink. Alternate directions and have good lighting. Doing it by hand sucks so I usually only mirror finish hollow ground blades!
 
Rookie25 said:
Are you flat or hollow grinding? What steel?When I mirror finish on a hollow grind I do it all on the grinder up to 2500,(a30,a16,a6 trizact) green compound, then pink scratchless. If flat, 600, 800, 1000, 1200, 1500, 2000, then green and pink. Alternate directions and have good lighting. Doing it by hand sucks so I usually only mirror finish hollow ground blades!
Click to expand...

I am hollow grinding D2 and 52100, straight razors. The 600 and 1200 belts I use are the 3M micron belts. You must like the fine Trizact belts.
 
razormaker said:
I am hollow grinding D2 and 52100, straight razors. The 600 and 1200 belts I use are the 3M micron belts. You must like the fine Trizact belts.
Click to expand...

The trizact belts are just how I was shown to do it. You really can do it with any of them but the lifespan of the trizact belts on a contact wheel is really good. I polish the flats all the way on the grinder, alternating directions. Then do the hollows. This helps keep the grind crisp. I use a lot of 440c so results may vary with other steels.
 
What Karl and Frank said!! You have to hand sand up to the point that you ask yourself if buffing afterwards is even necessary. Then buff, just barely touching the compound on the buffer, not the wheel.
I suggest to try with a little coupon of steel to get a start
 
D2 steel polished to a mirror finish. I think that's called masochism. I've tried but never got to the point where I was happy with the result. I blame the steel and my lack of patience. I followed proper procedure working back and forth through the grits up to 2000, and then up to .5 micron compound.

Theortically at .5 microns I'm in the ballpark of the size of light waves. Given the the compound was apparently friable I should be bellow the threshold of blue light. That is the 'scratches' should be narrower than a lightwave. My only legitimate excuse is that because D2 is significantly harder than stainless steels that I just wasn't being patient enough. The overall job was what I'd call 90% satisfactory. Most people would call it mirror (but I know it's not perfect). I would probably go with diamonds next time. <opinion> D2 is hard enough that the compound breaks down faster than it can work the steel </opinion>.

I prefer just grinding finer and finer until I'm dealing with microns. Flitz aparently works chemically, not abrassively which may help the last stage, I don't know, haven't used it

I think my D2 knife was hardened to about 62 ish rC. Depending on the treatment 52100 is even harder, 65 rC rings a bell. With the exception of using red before white rouge my guess is that it's just a lack of patience. From my experience VG-10 and 156cm are very similar in properties but I find VG-10 takes a polish much easier if they are the same hardness.
 
I've heard it mentioned quite a few times on this forum that some hardened steels don't lend themselves well to a mirror finish because they have "large" carbides like vanadium. If you dislodge one of these "rocks" during polishing or hand sanding at very fine grits, you basically dig a trench through the surface. I cannot attest to the correctness of this, but . . . in essence, it can be an exercise in futility with some steels.

Disclaimer: I do not use mirror finishes so I am speaking from hearsay, but believe the theory is correct because I believe I've experienced the same effect when hand sanding to 1500 grit.

Than again, clean buffs and equipment, hand sanding, and cross-directional sanding and polishing is probably more important, as noted above. One loose grain of abrasive from a 60 grit paper will ruin your work when buffing or final hand sanding the blade.
 
You must log in or register to reply here.
Back
Top