Mirror finish problem- help

R

Reivan

Joined
May 25, 2018
Messages
3
Hi,
im trying to make my first knife and get it to mirror finish and I could use your help guys :/

note pls that I bought cheap steel bar for construnction

Everything was fine until buffing... first I went from 40 grit sandpaper up to 3000 grit. Changing directions making 100% sure that I removed previous scratches. I ended up with light 3000 grit scratches in one direction on the blade. At that point the blade was basically mirror but at certain light/angle the scratches from last grit were visible. So I got a buffing wheels and blue/green/white compounds. I decided to go with white since I read that its best for mirror polish and light scratch removal...I used soft wheel of course. And that gets me to my problem- The buffing compound removed scratches from sandpaper but it makes completely NEW SCRATCHES on its own...I thought these things are supposed to hide the scratches not CREAT them :( I triet other compounds and also combinations like first blue (coarser) and then white (finer) and so on but every compound leaves light scratches ...am I missing something? how to get rid of scratches completely? Pls help
 
Reivan said:
I thought these things are supposed to hide the scratches not CREAT them
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The only way to remove a scratch is to remove all the metal down to the bottom of the scratch.
The buff doesn't hide anything it merely abrades the steel down to the bottom of the previous scratch depth.
If the scratches are too deep for that to happen all you get is shinny scratches.
 
But the compound itself is scratching the knife. There are no previous scratches just small light scratches made by the compounds... those I need to remove
 
Compound is an abrasive just like sandpaper only the grit is finer and it is in a paste or stick form...……. I think you have contamination in your wheel...…… Do you use a buffing wheel rake to clean it when you are changing compounds?...…. Have you ever cleaned it?...… start with a clean uncontaminated wheel and I think your problems will go away...….. Remember that when you go from a coarse to a finer compound you need to rake the wheel before applying the finer compound.....
 
that's the thing the wheel was new the compounds as well. Could it bee the steel? its not stainless or anything. Maybe it just takes a lot of time? I only buffed it for a like a 2 minutes maybe the scratches will eventually blend in? or my last gues could it be that the blade is not heat treated? its my first training knife and I just wanted to learn how to achieve mirror finish before doing anything else...
 
Reivan said:
the wheel was new the compounds as well.
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Still something could have contaminated the wheel or the compound has a problem . . .
Rake wheel.
try a new wheel from a different / better source
try different batch of compound

PS :
Reivan said:
There are no previous scratches just small light scratches made by the compounds... those I need to remove
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If you haven't be sure to wash the blade with some solvent or citrus cleaner to get all the compound off; maybe you are seeing fine micro streaks from the base of the compound.
 
I can mirror a finish by going through all my stones then finishing with a ceramic and sapphire stone.
Maybe the buffing wheel is just too much. It could be leaving scratches.
 
It has to be something to do with the wheel. After sharpening you should try going for that mirror polish on a strop loaded with a fine compound or diamond spray. Just learning stropping myself and to be honest it's not as hard as you would think. This was my first mirror edge try with a KME sharpener. I went from 140 grit up to 1500 grit then polished it with a 9 micron lapping film but the same can be done with a strop and some 9 micron Diamond gel or spray by making slow passes with little pressure. If you do try stropping make sure you designate a strop to a certain grit so you don't contaminate it with a coarse grit.
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I think the op is referring to mirror polishing his entire blade guys, not just the edge. Good luck with that, not something I have ever been successful in!
 
Reivan,
You're a goner.
If Josh can't do it with a power wheel . . .

I must admit that I have been successful doing it the way I said; going higher than 3,000 with the wet or dry (wet) (from what I have been reading lately maybe use oil) and using a flexible rubber block with the paper folded over the block.
Think : A WHOLE LOT OF WORK.
But
That was on a tiny Buck and a Henckles four inch paring knife that was not all that wide.
Not particularly hard or complex alloys . I hear some of the more complex alloys the best you can hope for from using a power buffer is a faint orange peal like surface . . . hence the grind lines we usually see.
 
razor-edge-knives said:
I think the op is referring to mirror polishing his entire blade guys, not just the edge. Good luck with that, not something I have ever been successful in!
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well that made it make more sense ... I haven't attempted that but just a nice satin can be a pain to keep that way ... don't think I'd want to mirror polish any full blades.
 
NEVER use a coarser compound than you already have on your buffing wheel- unless the coarser compound is all you will use on that wheel.
Wheel rakes don't remove buffing compounds from buffing wheels. You have separate buffs for each compound, and you store them in zip-lock bags.
You can spray your buff with WD 40 to make it cut smoother.
 
Bill DeShivs said:
You can spray your buff with WD 40 to make it cut smoother.
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People here some times hate on WD 40 but I was even taught by my mentor who, as a side line, sold Apple computers and set people up and tutored them , that I could pop the cover off a dot matrix printer ribbon cartridge that was dead and bring it back for a good long run just by spraying some WD on the ribbon.

OK that had nothing to do with anything.
Thanks for the education on the buffer though.
 
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