Buffing issues

Black cat

Well-Known Member
This could be similar to the post just below this but im not sure.
I do mirror finish on my blades but im having a few issues getting there.
I grind usually to about 400 grit surface then HT.
Then I grind off scale and do final grind up too 800 grit rhynowet sheets.
Im making every effort to remove all the scratches from the previous grits... Or at least that I can see. Lots of water or windex, blade is fastened to a sanding block and im using a sanding bar with the paper.
when in finished with the 800 grit it seems to be completely smooth.
next I take it to the buffer... Which is actually a little on the fast side.
I have clean wheels one is green compound the other is white.
I start with the green and it takes about an hour to buff one side.
The problem now is as soon as I start buffing it just seems to bring out the scratches!
Too me it seems like 800 grit isnt fine enough ? Or... The buffer is too fast ? Or... Theres something wrong with my technique. I just dont know which but it doesnt seem right that the most difficult step is the hours of buffing out scratches.
The other issue im running into is after the pass with the white compound wheel the blade has a hazy look. Under light it shows lots of fine scratches from the final buffing compound. Is this normal and how do I get rid of this haze ?
Thanks again ! :D
 
I'd like to see some pictures.

Buffing doesn't remove scratches, it really highlights them.
The way you posed your question seems like you used white after the green compound? It's normally the other way around.

Buffing compounds are often called 'cut', 'color' or 'cut and color'

bigger grit compounds can cut metal and shape a blade, color compounds add polish and will seem to change the color of steel to something like blue.
a medium grit compound can both cut and color
green is color and polish only
white can be cut or cut and color depending on the maker and several makers have multiple grits of white

If you are getting haze, look for something called 'pink no scratch'. it removes that pesky fog look from white compound.
 
Oh haha yeah... I think I have been using them backwards. I read the buffing link a few posts below just a moment ago and noticed I had the order reversed... No idea where I picked that up.
Yeah highlighting the scratches it what it seems to be doing.
I can get a few pictures tomorrow. Im not sure though if they will show much.
Thanks !
 
If you are sanding length wise on the blade and the scratches are running across , then you have not removed the scratches created by belt grinding. In this case the belts are worn or you are not using each grit enough. Frank
 
Im hand sanding lengthwise and the scratches are also lengthwise... That whats confusing me. I thought that 800 grit was high enough grit to not show scratches when buffing. If im leaving scratches... Idk id need a serious magnifying lens to see them. Even under bright light im not seeing any until I hit the buffer. Also after they show up after a buff ill go back and sand some. Ore with the 800 grit and it doesnt help. It seems like the 800 grit is just not fine enough. But again from what ive read 800 should be plenty fine enough. I think its something with my technique I just cant seem to figure it out. Im going to try 800 grit on tue lap wheel today then hand sand lengthwise with 800 then try buffing white then green and see what happens.
 
I make working knives, Culinary, Camp & a few hunters. I take my stainless blades to 400 grit and then use Scotchbrite belts through all four of them to have a nice working bright satin finish.

Just a suggestion. To me nothing looks worse that scratches on a mirror finish and that's gonna happen real fast on a working knife.
 
I make working knives, Culinary, Camp & a few hunters. I take my stainless blades to 400 grit and then use Scotchbrite belts through all four of them to have a nice working bright satin finish.

Just a suggestion. To me nothing looks worse that scratches on a mirror finish and that's gonna happen real fast on a working knife.

I agree. I just havent yet figured out how to do anything other than mirror finish. It takes a long time but eventually I do get mirror. Ive tried satin finishes but they never work out right. Are these scotchbrite belts like a regular grinding belt or more like a polishing belt ? Im going to try my first blued finish, only because somebody requested a gun blued knife.
 
First one is after hand sanding with 800 grit. Second and fourth are after buffing for 5 minutes with white compound you can see the bad scratches. I went back and hand sanded from the start again. Only seemed to make it worse. Oh sorry these are upside down. They always seem to do that when I post from my ipad for some reason.
 
I agree. I just havent yet figured out how to do anything other than mirror finish. It takes a long time but eventually I do get mirror. Ive tried satin finishes but they never work out right. Are these scotchbrite belts like a regular grinding belt or more like a polishing belt ? Im going to try my first blued finish, only because somebody requested a gun blued knife.

Scotch Brite belts are a finishing belt. Brown, Red, Blue, Grey is the order to use them. All knife supply houses sell them.
 
those look like 120 grit (or so) scratch marks. You didn't get them all out when you moved to 240 (or so).
 
those look like 120 grit (or so) scratch marks. You didn't get them all out when you moved to 240 (or so).

That had crossed my mind. Why cant I see them when im sanding ? I have a good light and I get right in close and dont see any scratches till I bring it to the buffer. Is there a technique to it ?
 
It will get easier to see them with practice. They are there and can be seen -- with time and experience.
After going from 120 grit (or so) to your next grit (240 or so, you usually double the grit each time) run it over the buffer using green for just 30 seconds or so...no more, you will instantly see what work you have left to do to remove the 120 scratches.

Buffing, unless you are using a specific set up, (like sisal wheel with black compound or grease based tubes that cake on abrasive) you can't remove scratches with buffing.
 
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