Hand mirror polishing a blade and fine sharpening

Joined
Jun 15, 2010
Messages
45
Hi there!
I really love mirror polished blades.

That's why I just started hand polishing my Gerber Big Rock (G1588). To do that, I started with a 120 grit electric drill sander, and then went on manually with some 240, 400, 800, 1200 and 2000 grit sandpaper sheets.

Now I've run out of grits and I want to bring the knife to mirror-polish conditions, and here is where I don't know what is best:
if:
A) Buy some 5000, 8000 and 12000 sandpaper/micromesh sheets and keep going in that direction
or
B) Buy the green&black Bark River Knives stropping compounds, and use them (first the black then the green) with a leather strop.

What method gives me the best results? What "grit" do the green & black BRK compounds have?

And, at last, which of the two methods is the BEST to obtain a perfect fine edge (sharpening) on a convex blade? Stropping with high-grit sandpaper or compound?

thanks!
 

Any Cal.

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Joined
Jan 1, 2006
Messages
1,404
You should already have pretty close to a mirror polish after the 2000 if you did everything right. I have used 1200 and then white rouge on a buffing wheel to get a nice soft mirror glow on steel.

I would skip all the polish tapes and stropping compounds and work with what you have easily available for the polishing. You need speed to make the white rouge work however, you can't put a small polishing wheel in a hand drill and have it work very well. I used a small wheel in a drill press on the highest speed, which seemed to work ok.
 
Joined
Jul 26, 2008
Messages
2,847
10,000 grit polishing film is roughly .5 microns
Green Chromium Oxide compound is roughly .5 microns. Applied to a soft backing such as a magazine or telephone book, either will give you a very nice mirror finish. (For a convex edge you want a soft substrate for your polish. For a beveled edge you need a hard substrate.)

From there you can use the DMT .25 diamond spray on a soft substrate as your next step. Then finish with bare leather as the silcates in that will be smaller than .1 micron.

That will give you a fine mirror finish.


Stitchawl
 

MTHall720

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Joined
Sep 21, 2010
Messages
2,723
Is there a good source for these grits as attachment wheels for a Dremel moto tool? Would the moto tool do ok for smaller blades?
 

Broos

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Jan 10, 2005
Messages
1,930
You can't just compare grits without considering the substrate. 10 micron sandpaper gives a much coarser finish than 10 micron abrasives on leather, for instance.
you have to look around and try it for yourself to really have a feel for the finish you can get with various abrasives. I won't let a dremel or a diamond plate near a blade I want to put a nice refinish on - the former leaves an uneven finish, and the latter will put scratches in a finish that take forever to remove. This and other info are mentioned on some knifemaker sites if you search around - they mainly use sandpaper and synthetic stones for finishing, and do it by hand. Check out Don Fogg's site - he is a master at finishing a blade and goes into detail on his site how he does it.
 
Joined
Dec 26, 2006
Messages
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Is there a good source for these grits as attachment wheels for a Dremel moto tool? Would the moto tool do ok for smaller blades?

Personally I wouldn't put a Dremel on my knives. Even the polishing bit. At 20,000 RPM, you can easily generate too much heat, and one little slip and you've messed up your edge.
 
Joined
Jan 24, 2007
Messages
1,626
If you don't have a buff the use the finest paper you have with a liquid polishing paste (Autosol) then progress to the liquid and a soft cloth.

Richard
 
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