Help me polish a honyaki

[Luftmensch]

400-~1k sandpaper leaves this kind of finish. Past 1k starts getting shiny instead of "brushed" looking.

For sure!

I can't remember which grit I used in posts [#36 and #44 above] - I think I like the 400~600 region. Above that, like you say, the metal starts to get pretty shiny - especially if you over work the paper (the abrasives break down into finer particles). If you want nicely defined scratch/brush marks, I recommend using fresh paper without any water (more aggressive). You use a moderate amount of paper (as it wears out quickly) doing this but you get the nicest lines.... At this point you shouldnt be polishing out any lower grit marks. If you want 600 grit brush lines, you should already have a >600 grit surface. When you switch to dry paper, you are only trying to control the final 'brush' marks....

 

[M1k3]

For sure!

I can't remember which grit I used in posts [#36 and #44 above] - I think I like the 400~600 region. Above that, like you say, the metal starts to get pretty shiny - especially if you over work the paper (the abrasives break down into finer particles). If you want nicely defined scratch/brush marks, I recommend using fresh paper without any water (more aggressive). You use a moderate amount of paper (as it wears out quickly) doing this but you get the nicest lines.... At this point you shouldnt be polishing out any lower grit marks. If you want 600 grit brush lines, you should already have a >600 grit surface. When you switch to dry paper, you are only trying to control the final 'brush' marks....

There's also sanding a step above your desired finish. Then going over it the grit you want.

I've also heard that some makers use worn out 400 grit sandpaper

 

[4wa1l]

Yeah I'm looking a for a brushed finish. I just don't have the patience for a full polish.

I was mainly hoping that a stone might be less work than constantly refreshing sandpaper but I think you're right about struggling to get an even finish. It's already a slog but looks like I'll just have to do it little by little with the sandpaper. I do have a very fine jnat nagura stone that I quickly tested out. It's not fast enough to remove the coarse scratches but it did bring out a surprising amount of contrast in the hamon and gave a fairly even finish. I'm pretty sure I'll use it as I near the end with some good slurry built up.

Thanks for all the tips! I'll post up a picture when I'm done (or have had enough).

 

[Luftmensch]

There's also sanding a step above your desired finish. Then going over it the grit you want.

Definitely. If using sandpaper - I just tend to over work the grit I am on before moving to dry paper - the paper breaks down quite quickly. But for honyaki... you are probably right....sanding one level above your final grit is probably worthwhile.

Yeah I'm looking a for a brushed finish. I just don't have the patience for a full polish.

Easy! Just use sandpaper I say.... it is cheap. You can get a 100mm by 5 metre roll for ~$15 dollars from Bunnings. I bend small strips around a thick piece of (3-5mm?) leather to give the paper a semi-rigid backing. It is flexible enough to deform into subtle dips but stiff enough to give you a wide contact area. It is also stiff enough to follow guides - if you want super straight/parallel brush marks you can follow a straight piece of scrap wood etc...

I was mainly hoping that a stone might be less work than constantly refreshing sandpaper

You do seem aware... but at the risk of over-explaining (in case you dont do much DIY stuff): use the sandpaper like it costs you $0.00003 per mm^2... because it does ... It only cuts fast for about 30 seconds (probably less!!) before you need to move to a fresh piece. Your time is worth more than the exhausted sandpaper! Overall you don't lose too much time if you pre-cut strips of paper... if you keep using fresh paper it can be quite aggressive and fast....

I'll post up a picture when I'm done (or have had enough).

Definitely... I would love to see progress!

 

[captaincaed]

There's also sanding a step above your desired finish. Then going over it the grit you want.

This worked well for me. Also, sanding both d directions at the final step on the same grit helped ensure the finish was even.

 

[M1k3]

Yeah I'm looking a for a brushed finish. I just don't have the patience for a full polish.

I was mainly hoping that a stone might be less work than constantly refreshing sandpaper but I think you're right about struggling to get an even finish. It's already a slog but looks like I'll just have to do it little by little with the sandpaper. I do have a very fine jnat nagura stone that I quickly tested out. It's not fast enough to remove the coarse scratches but it did bring out a surprising amount of contrast in the hamon and gave a fairly even finish. I'm pretty sure I'll use it as I near the end with some good slurry built up.

Thanks for all the tips! I'll post up a picture when I'm done (or have had enough).

Stones actually work really good to remove scratches. The drawback is it's really hard to do the whole blade.

 

[tostadas]

I've been playing around with a few things recently that have shown some interesting results. Havent tried it yet on the honyaki, but that will be next when I have some time.

Sandpaper up to slightly higher grit than I want to finish at, so in my case I went up to i think 1200 or 1500. Then etch with hot vinegar and/or hot coffee. Still figuring out which gives better results. Then I lightly brushed the finish with some king 800 mud on a scrap of felt cloth.

If you are doing sandpaper alone, it's hard to end up with a matte finish. It would be more like a brushed finish.

 

[cotedupy]

You can work with scratches!

When I thin my daily drivers, I feel compelled to go through the process of refinishing the blades. I do a brushed finish on the flat of the blade, and a haze on the bevel. Getting a good satin brushed finish can almost be as maddening as any other type of polish. It depends what standard you hold yourself to!

Before getting to the brushed finish, you can polish the surface to the final grit level you want, or even one git higher. At that point I have found good success doing more or less what @lemeneid said. Knife below and abrasives above. Put the aesthetic scratches on the blade by doing very controlled passes across the surface. I even use ruler to ensure I am keeping the passes straight. The lighting in this photo is super harsh and revealing:

View attachment 87703

This is the front quarter of a 210mm gyuto. The brushed finish is as straight as I could manage! Drove me mad... had to do many resets. On average I would consider this finish to be 70% perfect. Suits me fine. Again, it is a knife that is to be used. It is a dirty 5000 on the core steel, a painfully done 600 grit brush on the face and a dirty fingerstone finish on the bevel. It looks quite different in normal lighting. The brushed finish is quite bright and shiny, the bevel is a nice dull kasumi and the bevel is mirrorish. There are some nice contrasts.

On uchigumori (bench and finger stones)... Sword polishers have a collection that they can match to the steel they are working with. As @nutmeg pointed out, yours is likely too hard. It is easy to get hung up on tradition. Anything that gets the job done is fine by me! You don't have to use uchigumori . As you noted in your previous post, you may find stones better matched to your knife. I have a Shobudani stone that reliably leaves a lovely scratchless kasumi finish. It may be too cloudy for hamon though. Experiment with what you have in your tool kit!

That is superb. Love it!

 

[Luftmensch]

That is superb. Love it!

Thank you kind sir!

The best part is, you don't need a fancy workshop or tools/stones. Or much skill really.... just patience and stubbornness