Cant get a satin finish...

[Jeremiah Rostig]

Thanks! its 1084. So you think a mirror finish on a large chopper would look ok ?

of course a mirror finish is ok, if You dont mind the effort.to get a mirror finishes You need a polishing machine, polishing wheels and polishing compounds in coarse, medium and fine....because polishing to a mirror finish by hand is something for the Titans.

in the case of Your blade I would finish to grit 400 and sisal polish(coarse) length wise and You are done.

 

[Jeremiah Rostig]

Call me crazy- but I've had pieces of steel that seemed like no amount of sanding would eliminate mysterious scratches that seemingly appeared around 600 grit, running in a direction that I had not sanded in at all.

I just had another issue that was driving me insane, but I figured it out. This may be what you're seeing-

I could get a good looking scratch pattern, and then I'd get crazy scratches from nowhere. I actually thought my paper towels were scratching the finish when I'd wipe the surface to change grits. (I sand with WD40).

I was half-right. I started shooting the blade with windex to lift any residual swarf or grit from the surface- and LIGHTLY wiping in the same direction I had just been sanding.

I discovered that my paper towel was picking up grit I couldn't see and then I was raking it across my finish and scratching my blade.

I have never had this problem before until I started using this brand of paper towel (el cheapo).

Using this windex / wiping direction step between grits restored my sanity. I also think it's the solution to my mysterious scratch problem I've had at times that I mentioned above.


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John WD40 is something only for daily maintenance of machines and tools.
try cutting oils, because they are designed for that.....you will feel and see this, paper cuts better,longer and the result is more even. those cutting oils are a big help to get some better performance out.

 

[Doug Lester]

What you're going to get here about mirror finishes, or any finishes, is going to be personal opinion. I personally would not put a mirror finish on anything but a collectors knife. Some real eye candy. (Not that I'm capable of creating it.) A mirror finish will be quickly ruined with use so I look at it as not worth the effort. If others want to do it it's up to them.

Doug

 

[John Wilson]

John WD40 is something only for daily maintenance of machines and tools.
try cutting oils, because they are designed for that.....you will feel and see this, paper cuts better,longer and the result is more even. those cutting oils are a big help to get some better performance out.

Do you have an oil you would recommend? Or just any kind of cutting oil will do?


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[Jeremiah Rostig]

What you're going to get here about mirror finishes, or any finishes, is going to be personal opinion. I personally would not put a mirror finish on anything but a collectors knife. Some real eye candy. (Not that I'm capable of creating it.) A mirror finish will be quickly ruined with use so I look at it as not worth the effort. If others want to do it it's up to them.

Doug

Doug, of course You are right, I would do neither, but I just wanted help "Black cat" to find his informations, so that he can decide and collect experience.
it is fact that high mirror polish, prevents better rust, less friction in the cut and is more stable against scratches than a satin finish, wich always has in micro terms more opened matrix left, high polished blades are the tougher ones, ,,,well some fellows might disagree, but it is an old school fact.
satin finishes came with high alloy/stainless steels and are only cosmetics, but in fact counterproduktive.....in my opinion, and I am pretty much old school:biggrin:

 

[Jeremiah Rostig]

Do you have an oil you would recommend? Or just any kind of cutting oil will do?


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John, I had a hard time finding cutting oil in Bangkok, the first one I worked with is from Australia and was an excellent product, but like it is always in Thailand, went to the same shop, sold out....never found again.
so I was happy to find at least another brand, it is from the states and it is ok, the Australian oil was better but I got used to it and it works fine.
...I guess any cutting oil will do, just try.They cost a few bucks and they are worth it,....first can lasted 7 years!
I mainly use it for blade finishing and sometimes for drilling, it is amazing how this oils can push a nearly worn down drill bit to new peformance.
I really want to know what kind of additives are in and how they work....

 

[Black cat]

Wow lots of good advice here and ive been putting it all to the test to figure out where im going wrong here.
Ive changed my grit progression, changing the direction of sanding and using cutting oil and so on.
This has helped A LOT.
Changing the direction was awkward at first but makes such a difference! I now can see all the scratches that I was unaware of. Cutting oil helps bit I want to try the windex and wipe idea... I suspect there is grit from previous passes that is imbedded in the surface as well.
Im still torn on the finish however. A mirror finish is pretty easy for me but I jist want to get the hang of a satin finish.
This is somewhere between a show blade and a beater. By that I mean its my personal blade to showcase a few skills but I also plan to use it as a chopper brush cutter this summer. So I was thinking a satin finish would be easier to maintain. However ive also hear a mirror finish is easier to maintain lol. For me... Repairing scratches on a miror would ne pretty simple, a little difficult on a satin.
Either way... Depressed lol ive put in something like 24 hours of sanding into the blade now and its worse than when I started Because I have had to start over the progression a few times and correct a few mistakes. Now the blade is getting paper thin and too flexible. Theres no material left to make another mistake. And its cost me around 200 dollars in sandpaper now. I suppose thats just part of life and learning though. Now I onow the mistakes ive made and im sure doingnthis one again would be much quicker and less sanding.
I think im going to put this one aside and start from scratch (no pun intended) lol
I dont want to destroy this one by going any farther but I dont think I have the skill to complete it at this point without sanding it to death. If and when this one is finished its the third complete knife I will have made. I have MANY others in various stages of completion for other people.

 

[John Wilson]

Thank you, Jeremiah.

Black Cat- I also agree that a mirror (or near-mirror) is easier to maintain than a satin finish. A satin finish has the opposite problem that a mirror has. I find- especially with a kydex sheath, that a satin finish that rubs in the same spot will become polished in that area. So yeah- you might not have a scratch, but you have these random shiny spots or streaks. Which is worse? I guess that's a question of personal preference.

I like a near-mirror finish. It looks haze gray at a glance but laid against something the reflection looks like a mirror. I get this by going to 2000 grit by hand and then stop. No buffing. My clients love it on hunting knives. It's much easier to keep clean and blood washes off easily.

On my culinary knives I go to 800 grit. A mirror sticks to veggies whereas 800 releases sliced pieces better.

2000 grit

800 grit


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[Black cat]

John Wilson I like the look of those. Thats exactly what I was aiming for with about 800 grit or even the semi mirror.
I got to that point but the sanding lines on mine didnt look anywhere near that good. Now that im sanding in different directions im seeing a lot more missed scratches. I have a feeling that was the problem. Thanks

 

[John Wilson]

Thank you very much. The 2000 grit finish only takes about 15 more minutes per side than the 800. (1000 grit + 2000 grit). Adding in 1500 will knock out the haze, but the haze is part of the look. The key is finishing each grit from 600 on by sanding only in the final scratch pattern direction. Yes, I realize this breaks from the correct way to do it. It's just the way I get the look I like.

So from 600 on, sand back and forth until you are done with that grit, then take another little square and drag only from the ricasso to the tip. (From 600 on I only sand in the direction I want my final scratch pattern to be.). I don't want a perfect mirror. I like it frosted. But the scratches have to be in line or else the frost looks like random scratches instead. I know I'm leaving some residual scratches - that's why it's hazy. So long as the scratches line up it looks satin.

Yes- sanding by alternating 90 degrees each grit was a gigantic help to me as well. If it seems like more work, that's because it is. I realized how many scratches I was leaving behind at grit changes once I was able to see those residual scratches.

I stand by the windex/wipe with the sanding lines technique. You'll be shocked at what comes up with the towel when you float it off the surface with the squirts of windex. I was spending all that time getting rid of every last scratch and then dragging grit down the blade. I thought I was going crazy.


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[nine9jack9]

Scotchbrite belt

Had a similar problem. Needed to get finish that would be acceptable on the final product and that would allow me to get away from hand sanding finish to a great extent. In my neck of the woods there is an abrasives wholesaler that also caters to the custom knife-making crowd. In any event he turned me onto Scotchbrite belt, he had at least three different levels of finish. They put a nice satin/brushed finish look to the knife and had no problems polishing out the troublesome area at the plunge line. They last a long time and unlike a Gator/ceramic belt they don't imbed with grit and cause a larger scratch. If you have steady hand/light touch they won't round over edges, unless you want to. I've seen guys use them on kitchen knives to hunters. Hope this helps.

 

[John Wilson]

I bought two scotchbrite belts. One fairly course and one finer. I'm doing something wrong. They definitely do a great job on blending in and smoothing, but I can't get anywhere close to a hand rubbed finish. But I see that plenty of people can.

I found that I can get pretty close by running them on my 10inch contact wheel, but I can't get much out of them on a flat platen.

Is there a technique to them, or some compound I should be applying?


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[wall e]

This is past where your wanting to get?
This is hand sanded to 2k, if your trying to get all the scratches to disappear it will become rflective if you continue sanding on the blade.

 

[scott.livesey]

another option would be a wool felt belt and the polishing compound of your choice. here is a source for the belt http://www.supergrit.com/products/products_belts-misc
as far a secret technique, practice and low belt speed. i have found that belts finer than 120 last longer and work better if run wet at low speed(less than 600 FPM). if i were a rich man i would have a dedicated 2x72 just for finishing.