How soft does metal have to be for a scotch-brite pad to wear it down?

J

jerrac

Joined
Jul 31, 2021
Messages
7
Hey all, here is my second post. Hopefully in the right forum. It was this or the general forum as far as I could tell...

Anyway, I took a risk a few months ago and ordered some Damascus knives from a maker in Pakistan via Alibaba. They arrived a bit dirty, and seemed rusty. I just worked on cleaning them today, and in the process I seem to have been able to wear down the etch of the Damascus pattern. With just elbow grease and a green scotch-brite pad.

Here's a couple photos, captioned with which is which:
https://imgur.com/a/3SS2W0R
Sorry for the poor lighting.

The blades are supposed to be around 60hrc.

Is a scotch brite pad really strong enough to wear that down? Or did I get gypped?

Thanks in advance!
 
jerrac said:
Hey all, here is my second post. Hopefully in the right forum. It was this or the general forum as far as I could tell...

Anyway, I took a risk a few months ago and ordered some Damascus knives from a maker in Pakistan via Alibaba. They arrived a bit dirty, and seemed rusty. I just worked on cleaning them today, and in the process I seem to have been able to wear down the etch of the Damascus pattern. With just elbow grease and a green scotch-brite pad.

Here's a couple photos, captioned with which is which:
https://imgur.com/a/3SS2W0R
Sorry for the poor lighting.

The blades are supposed to be around 60hrc.

Is a scotch brite pad really strong enough to wear that down? Or did I get gypped?

Thanks in advance!
Click to expand...

Both of the Damascus knives from Pakistan that I have measured 50 - 55Rc with my Tsubosan files. But they are pretty, so I'll keep them.
 
Scotch-Brite is aluminum oxide abrasive in a plastic binder. Aluminum oxide is conservatively 2.5X as hard as hardened cutlery steel. Most any blade finish or in most cases, the steel itself, would be easily scratched, altered or polished away by Scotch-Brite. Need to be careful in how you use it.
 
Last edited:
Ordering “Damascus” knives from Pakistan is a crapshoot at best.
It appears you removed the oxides left from the etching process which will happen to and etched blade. It’s difficult to tell if you wore down the metal, I kinda doubt you did by only hand rubbing with a scotchbrire pad.

Yea you most likely did get gypped.
 
Thanks for the extremely fast replies!

Obsessed with Edges said:
ScotchBrite is aluminum oxide abrasive in a plastic binder. Aluminum oxide is conservatively 2.5X as hard as hardened cutlery steel. So, most any blade finish would be easily scratched or polished away by ScotchBrite. Need to be careful in how you use it.
Click to expand...
Ok, that's interesting. So, don't use scotch-brite.


3fifty7 said:
It appears you removed the oxides left from the etching process which will happen to and etched blade.
Click to expand...
Would scrubbing with baking soda and a toothbrush do the same thing? That's one of the methods I found for removing rust.

Any other suggestions on cleaning them up?

I mainly bought these for the looks. I wasn't expecting very high quality, but I'd like to at least get them shined up enough to look pretty.

*goes off to research cleaning the rust off some more....*
 
jerrac said:
Thanks for the extremely fast replies!


Ok, that's interesting. So, don't use scotch-brite.



Would scrubbing with baking soda and a toothbrush do the same thing? That's one of the methods I found for removing rust.

Any other suggestions on cleaning them up?

I mainly bought these for the looks. I wasn't expecting very high quality, but I'd like to at least get them shined up enough to look pretty.

*goes off to research cleaning the rust off some more....*
Click to expand...
Need to be very careful in trying to 'shine' or polish any damascus finish. The dark, contrasting oxide left by the damascus etching process will be removed if anything harder than the oxide is used to scrub or polish it. That means avoiding most polishing pastes, most of which are aluminum oxide, and Scotch-Brite & other products like it. Years ago, I made the mistake of polishing a damascus blade with some aluminum oxide polishing paste (either Simichrome or something like it). The pattern of the steel can still be seen now, but the dark-contrasting oxide was rendered a dull grey. So it's quite a bit more drab than it used to be. Live & learn...

Baking soda is soft enough that it won't scratch a finish like this. So, for some gentle cleaning of red rust, it could work.
 
Last edited:
With Scotch-Brite or any other AlOx-based abrasive product, the RC hardness of the steel really won't matter much. Even HRC 60+ isn't nearly hard enough to resist being altered by the AlOx abrasive in the pads.

Other factors, like the shape of the abrasive grains (sharp/jagged-edged or blocky/rounded/blunt grains) or the softness of the binder (or the pad itself) can limit how deep the scratches get. But there's no way to prevent scratching altogether with products like these. If one has ever used a Scotch-Brite pad to scrub a sharpened blade, the edge will be quickly dulled if it makes contact with the pad. That's a more obvious indicator as to what the abrasive in the pad is capable of doing to the steel.
 
Last edited:
I cannot see the rust in your pics, I’d start cleaning with least intrusive measures first.

A lot of WD-40 and cloth, a lot of WD-40 and a nylon brush, a lot of WD-40 and a toothpick.
 
I worked with Scotch Brite to clean aluminum parts at a previous job. There are different "grades" of it, like sand paper. Green was the go-to if you wanted to remove the corrosion prevention coating. White was the one to use for light cleaning of a coated piece. I see blue and green in the grocery stores, and guess that blue is a similar grade as white. You do not want to use green Scotch Brite on any coated frying pans or anything delicate.
 
I'd suggest using fine steel wool rather than unitized abrasive pads.
 
000Robert said:
With my Tsubosan testing files. They work pretty good but only give an approximate hardness. But at least you'll know the steel was hardened.

View attachment 1610880
Click to expand...
How do you use them? Is it as simple as: If they scratch the metal, the metal is softer than the file. And: If they don't scratch the metal, the metal is harder than the file?
How hard do you press on them?

3fifty7 said:
I cannot see the rust in your pics, I’d start cleaning with least intrusive measures first.

A lot of WD-40 and cloth, a lot of WD-40 and a nylon brush, a lot of WD-40 and a toothpick.
Click to expand...
WD-40 and paper towels already made a large difference. Dad and I can't believe we didn't think to try it earlier. I got some nylon brushes and will be using them soon as well. The knives are already looking a lot better. :)
 
Sharp Steel said:
I see blue and green in the grocery stores, and guess that blue is a similar grade as white. You do not want to use green Scotch Brite on any coated frying pans or anything delicate.
Click to expand...
Yes my friend, you are quite correct, the blue is the less abrasive one. It is the one recommended for all stainless steel cookware, i use it to clean my seasoned stainless steel fry pan without an issue, and my seasoned cast iron skillet and fry pan. Hope this helps for future reference. Have a good weekend.
 
The green Scotch-Brite pads are good for applying a satin finish to bolsters on knives in brass, 'nickel-silver' or stainless. AND, they'll do the same to the blades and springs, if you're looking to clean up scratches & scuffs.

I gave this 4-dot Buck 112 the green Scotch-Brite treatment yesterday, and also to a Buck 111 a while back. The high-polish brass or nickel-silver bolsters had looked good before on both. But they also show every fingerprint and smudge, which ends up becoming part of the finish, being oxidized into the surface. The satin left by the Scotch-Brite does a much better job concealing those fingerprints and smudges on knives that get handled a lot. I carry the Buck 111 every day lately, and the finish holds up well.

xNKM6Z4.jpg

XXVa4LQ.jpg

UDihLj4.jpg
 
Many years ago, I did not realize that the green Scotch Brite pads had abrasive imbedded in them. I found out the hard way. Scrubbed some stubborn gunk and water spots on my windshield. Ended up with some very fine scratch marks in the glass. Not bad enough to replace the wind shield. Lesson learned.
 
jerrac said:
How do you use them? Is it as simple as: If they scratch the metal, the metal is softer than the file. And: If they don't scratch the metal, the metal is harder than the file?
How hard do you press on them?
Click to expand...

If the Tsubosan file is harder than the steel it will bite into the steel. So when the file bites, you go to the next softer file until the file skates across the steel without trying to bite into the steel. So, if the Rc60 file skates and the Rc65 file bites, you know that the steel is harder than Rc60, but softer than Rc65. The Rc60 may still scratch the finish of the blade, but it will not bite into it if the file is softer than the steel. So test the blade in a place that won't make your blade look tacky. I test the files on or near a sharpened edge so if I scratch it the scratch will be gone the next time that I sharpen it.
That also helps to see if the heat treat of the edge apex was damaged at the factory, or by someone else, by them using a dry belt grinder.
 
You must log in or register to reply here.
Back
Top