Learning How to Put a Satin Finish on a Blade

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Sharperthansticks

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I have a FFFW (Ferrum Forge Falcon Wing) that needs some work done on it. Part of the work is anodization, and part of the work is refinishing the blade so it has a satin finish. What prompted me to want the blade to be refinished is that it got a scratch in it which I removed using Flitz and a Dremel which then left the blade looking cloudy instead of having that nice satin finish that I love. Initially, I was barking up the wrong tree, using Flitz and optical grade potions and buffs. I eventually realized that those were going to move me towards a mirror polish, when I actually wanted a satin finish, instead.

I started looking around Amazon and the Internet, and I realized that I needed a wheel abrasive, so I bought a bench grinder. The thing is, I think that's overkill, and I may return it, because last night I had some preliminary results from a Dremel approach that is encouraging. (You may think otherwise and laugh at the picture; I encourage you to see it as an intermediate state, instead of the final product, as I am still learning.)

The process did not unfold completely neatly, but instead of going through every misstep, I'll tidy it up and show the arc of improvement:
  1. I decided to experiment on a Kizer that I don't mind ruining.
  2. I went to Home Depot and got Dremel parts 511E and 512E, which are abrasive buffs. They look a little like the seed head version of a Dandelion, except, instead of having spherical symmetry, they have cylindrical symmetry, because the top and bottom of what would have been the sphere have been chopped off.
  3. I clamped the Kizer into my bench vise so it's parallel with the ground.
  4. I put the lowest grit head in the Dremel and used it somewhere between 5k-rpm - 15k-rpm. The grit is probably 120 or so. I passed the Dremel back and forth along the direction of the blade and easily scratched coarse lines into the blade. When the lines looked reasonably clean, uniformly distributed, and they weren't changing, I stopped.
  5. I moved to the 180 grit and repeated this process.
  6. I moved to the 320 grit and repeated this process. Unfortunately, after a while, the head sort of exploded, and all of a sudden it quickly started ruining my work, carving ugly grind lines into what was relatively smooth. I tried to muscle it back to smoothing out the grind lines, but to no avail.
  7. I went on Amazon and bought 40 cheap, no name Dremel heads in grits 120, 180, 320, and 400. I plan to start again from 180.
Posted here is a picture of the knife after it got "ruined" by the exploding Dremel head. It's certainly not perfect -- especially after the 320 grit head exploded -- but I think I'm starting to get somewhere. Hopefully, after doing the 180 grit, 320 grit, and 400 grit, it'll look a lot better. I also have some higher grit Scotch-Brite wheels coming that go into a regular electric drill.

I realize that I didn't mask the swedge; I was eager to see preliminary results on this test. Also, I'm not the best with a FlexShaft/Dremel; the Dremel kept getting sucked down into the blade.

If you guys have any constructive advice, please feel free to share.


cU67DO1.jpg
 
I wouldnt use a dremmel to do what you’re trying to achieve. That’s just me. You could create a low spot very easily. A belt grinder would work better, give you a larger more uniform grinding surface. Also you don’t want your dremmel or grinder spinning at 15rpm. 5k may still be too much. I think doing it by hand, for me, would give the best finish.

You may need to end at somewhere in the 600 grit range to achieve a satin look. Maybe even 800.
 
Thanks for the comment. It was a struggle to find wheels for a 6" bench grinder that are labeled with grits. Instead, they have vague titles. Perhaps I'll get an 8" bench grinder. I think a belt grinder would be a bit unwieldy for an apartment, but I could look into it.
 
The way I use to refinish old straight razors was with wet or dry sandpaper working from around 200-400 grit up to 3000-5000 grit using around 3 sizes in between. Once you get finished with the 3000-5000 grit, which will have a half decent shine then, a good metal polish such as Flitz works well to finish it off. Sand only parallel to the edge. This all takes time but it works very well if you have the patience. But for god's sake ditch the Dremel. Word of caution, watch your fingers, if you have knife gloves, wear them. Lay the knife blade on a good secure flat area preferably wood when working.
 
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I have done quite a bit of polishing on knife blades with the wet or dry sandpaper, and never could find over 2000 grit locally. Using worn 2000 put on a very good shine, but going further with finer than 2000 would be easier.
 
If I remember correctly I always had to order mine on line, probably at that largest on line store. Don't think I found in locally.
 
If you have a walmart nearby, they usually have 2k, 3k, and 5k grit sandpaper in the auto section.
 
Phil in Alabama said:
I have done quite a bit of polishing on knife blades with the wet or dry sandpaper, and never could find over 2000 grit locally. Using worn 2000 put on a very good shine, but going further with finer than 2000 would be easier.
Click to expand...

If you are still in the market consider 3M Wetordry Polishing Paper. The backing is very flexible and the slurry coat seems to work longer than very fine top coated wet/dry paper.
 
ED Carry said:
The way I use to refinish old straight razors was with wet or dry sandpaper working from around 200-400 grit up to 3000-5000 grit using around 3 sizes in between. Once you get finished with the 3000-5000 grit, which will have a half decent shine then, a good metal polish such as Flitz works well to finish it off. Sand only parallel to the edge. This all takes time but it works very well if you have the patience. But for god's sake ditch the Dremel. Word of caution, watch your fingers, if you have knife gloves, wear them. Lay the knife blade on a good secure flat area preferably wood when working.
Click to expand...
That's interesting information for a different project, but I've described the desired outcome of my project to be different than what you're describing; I don't want my knife to shine.
 
Phil in Alabama said:
I have done quite a bit of polishing on knife blades with the wet or dry sandpaper, and never could find over 2000 grit locally. Using worn 2000 put on a very good shine, but going further with finer than 2000 would be easier.
Click to expand...
As my post mentioned, I'm not looking for the blade to shine. That would be a different project.
 
please watch nick wheeler on how to satin finish he does great job of showing all steps again no power tools needed good luck
 
As a maker I can tell you how to get a satin finish on a blade, and it only involves sandpaper and elbow grease. The videos by Nick Wheeler are great. And there is absolutely no need to go beyond 400 or 800 grit. 2000? 2500? 3000? These are for obtaining mirror polish, these grits are waaaaay too fine for a satin finish.

Basically you start with 120 grit paper and remove any and all old scratches. Sand in only one direction. (Tip to tang, or edge to spine, or diagonal). If you need coarser paper, drop down to 80 grit. Once you have all previous scratch marks gone, move up to 220 grit and do the same thing, erase the 120 grit scratch marks by sanding in a different direction than your previous grit. Then move to 400 and do the same, just in a different direction. Stop here or move up to 800 (or even 1200 if you want a finer finish). Alternating scratch patterns makes it easy to tell that all scratches from the previous grit were erased. That’s really all there is to it. What I do on most knives is take it to 400 grit with the sanding direction tip to tang, then I use a scotch brite belt in the same direction (helps to blend sanding lines together). Then I polish the blade with mother’s mag aluminum polish. Then I go to 800 grit and, using the same direction tip-tang, lightly establish the 800 grit on top of the polished 400 grit. Makes for a superb satin finish.

I would ditch the Dremel tool for this. Just a few sheets of sandpaper is all that’s needed. 120, 220, 400 (800 and 1200 if desired).
 
Sharperthansticks said:
That's interesting information for a different project, but I've described the desired outcome of my project to be different than what you're describing; I don't want my knife to shine.
Click to expand...

Yup, you're right, sorry. "samuraistuart" has the straight skinny above.
 
samuraistuart samuraistuart I haven't seen the Scotchbrite and Mag Polish steps in satin finishing instructions before. What changes if either or both of these steps are left out? Would stepping 400 > 800 > Mag Polish > 800 be useful if one does not have a belt setup? Do you use Rhynowet Redline or something else?
 
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I polished a lot of old 1911 pistols for years and the best way is sandpaper wrapped around a dowel or a stick or a block. It takes a long time and a lot of sandpaper but it's worth it. I have burned through 2 Dremels in 25 years and they are great tools - but not for fine finish work. They will round off corners and grind valleys in your work.
 
I’m not saying that the scotch brite finish and metal polish steps are necessary AT ALL. The SB belt just helps to blend lines together. The polish just helps brighten it up (and the polish will be totally negated if you “go to town” with abrasives on top of it, whatever grit they are).

My point being that this method, done correctly, gives me the finish “I am after”. I’m not in any way saying it is necessary or better. I’m just divulging my go to method.

No need for any belts, fellas. No need for the scotch brite belts. I have them. I use them. They work for me. They’re not necessary!!! They just aid the process along and make a cleaner finish “in my shop”.

Yes. Rynowet paper. Excellent stuff. I use 80-1500 paper. Rarely above 800. Usually it’s 80, 120, 220, 400, 800.

Bottom line....scotch brite belts and metal polish are not necessary at all. All that is necessary is sandpaper. Stop at whatever grit you think looks good to you. For stainless steel any grit is acceptable. For carbon steel, the finer the grit the better the corrosion resistance. I say a minimum of 400. For kitchen knives I double that and say a minimum of 800. And again, this is personal opinion. I usually always will follow up with whatever is my final grit (stainless steel or carbon steel) with a mother mag aluminum polish by hand.
 
samuraistuart said:
As a maker I can tell you how to get a satin finish on a blade, and it only involves sandpaper and elbow grease. The videos by Nick Wheeler are great. And there is absolutely no need to go beyond 400 or 800 grit. 2000? 2500? 3000? These are for obtaining mirror polish, these grits are waaaaay too fine for a satin finish.

Basically you start with 120 grit paper and remove any and all old scratches. Sand in only one direction. (Tip to tang, or edge to spine, or diagonal). If you need coarser paper, drop down to 80 grit. Once you have all previous scratch marks gone, move up to 220 grit and do the same thing, erase the 120 grit scratch marks by sanding in a different direction than your previous grit. Then move to 400 and do the same, just in a different direction. Stop here or move up to 800 (or even 1200 if you want a finer finish). Alternating scratch patterns makes it easy to tell that all scratches from the previous grit were erased. That’s really all there is to it. What I do on most knives is take it to 400 grit with the sanding direction tip to tang, then I use a scotch brite belt in the same direction (helps to blend sanding lines together). Then I polish the blade with mother’s mag aluminum polish. Then I go to 800 grit and, using the same direction tip-tang, lightly establish the 800 grit on top of the polished 400 grit. Makes for a superb satin finish.

I would ditch the Dremel tool for this. Just a few sheets of sandpaper is all that’s needed. 120, 220, 400 (800 and 1200 if desired).
Click to expand...
Thanks for this. I read it a few times and a am a little confused, so I'm going to rewrite this in a slightly more formal way, putting the parts I'm confused about in red. If you wouldn't mind, maybe you could explain those parts a little more. I'll put questions in brackets, too. Here's your procedure, rewritten:
  1. Start with 80- or 120-grit sandpaper, depending on how coarse paper you need to get out existing scratches/lines on the blade. Choose a particular (back-and-forth, linear) sanding direction and sand in that direction until all previous scratches/lines are gone.
  2. Sand with 220-grit paper, changing the sanding direction (but again using only one direction), and continue to sand until the lines made in the previous step are gone.
  3. Repeat the basic step with 400-grit paper.
  4. Use a Scotch-Brite belt of 400-grit. [On a belt sander? By hand? Since this is the same grit, how long do you sand? Where do you purchase this belt, anyway?]
  5. Polish the blade with Mother's Mag Aluminum Polish. [With a soft cloth? Won't this blur the lines? How long do you polish?]
  6. Polish for a little while [how long?] with 800 grit.
Thanks for your help, man.
 
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