cork belt ?

tuskbuster

Well-Known Member
just got some cork in from the Boss,thought there was a screw up ,man are they got some texture to em . they are 600 grit,whats the correct way to break em in as ive read around,HELP dont wanna screw em up not knowing
 

Rudy Joly

Well-Known Member
They tell you to run the belt for quite a while with the end of a steel bar pushing into it. That seems like it took forever the first time and I still didn't get an even finish.
Next I used a flat concrete paver brick with moderate pressure, then a little massaging with a steel bar to even it out, that worked like a charm. The intent is only to get those gnarly bumps off, so pay attention. Don't use a regular red brick, it will likely stain the belt or inpregnate brick dust in it. They last a good long time and I spruce up the face with grey compound every now and again.

Rudy
 
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rhinoknives

Well-Known Member
The first time I received cork belts I was also puzzled with the texture of the grits.

Here's what I do to break them in, Load them up with Green Crome and run them at at least 50-75% speed, take a piece of harden steel from a botched knife that has been finished to the grit below the cork you are using and press fairly hard. The grit will flaten out in about one knife of polishing and then you will be ready to work on your keeper blades.

The blades get hot very fast so I personally keep dunking in a fresh clean pail of water so that they never get about about 200 degrees or boiling water. Cork are a whole different animal and you may need to experiment to find what works best for you. Also with all that green chrome rouge getting in the air, make sure to wear your resiperator while using them.

Hope this helps.

Laurence

www.rhinoknives.com
 

BossDog

KnifeDogs.com & USAknifemaker.com Owner
Staff member
cork belts are funny stuff. They put a really nice finish on a belt once you knock off the high spots.

SRJohnson uses them with green chrome loaded on the belt. A technique he carried forward from his days in Ron Lovelass shop.
with practice you can go from an 80 or 120 straight to a mirror finish. I've done it.
They do make a blade hot quickly so then you dunk and then you get green chrome all over. Then you look like a martian.

You don't have to use buff compound on them if you aren't going for a mirror finish and they leave their own, nice satin finish depending on the grit.
They last forever, years literally, if you use them with green chrome.
 

Frank Niro

KNIFE MAKER
I believe the stripping and then loading with rouge was just a development . There are the usually sizes of cork belts as other types. They are used extensively in the glass working business. The problem for knife makers is that if you use them as they are for grinding without a rouge, they will plug off and stop removing metal. Going over them with a belt cleaner rubber will clean them up some. There are a couple of types of other rouge that can be used but man if you think the green rouge creates a mess try one of those that are like grease. I believe the grinding material in the belt is silicon carbide not aluminum oxide. I still have one on hand in 150 size I use for sizing and cleaning edges on glass platens when I change them. I've seen knives finished in the SR Johnson way . Boy do they shine when the meathod is worked out ! Frank
 
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Josh Dabney

Moderator
Surprised no one mentioned this yet. I soaked my cork belts in water for about 10 minutes before breaking them in. Cant remember where I picked that tip up but it's ok to run cork belts wet also.

I've never run any rouge on mine and have gotten great satins with them. A 600 cork finish looks great for a machine finished blade IMHO.

-Josh
 

Sampson knifeworks

Well-Known Member
I use mine occasionally for a machine satin finish. After breaking them in I use WD-40 sprayed on the belt, keeps the heat down. Kinda messy and the WD-40 dries up and needs replacing quite often, but every time its applied they work like new again. Also train the edges of the belt just like other belts and they do wonders for refining your shoulders.
Clint
 

rhinoknives

Well-Known Member
Surprised no one mentioned this yet. I soaked my cork belts in water for about 10 minutes before breaking them in. Cant remember where I picked that tip up but it's ok to run cork belts wet also.

I've never run any rouge on mine and have gotten great satins with them. A 600 cork finish looks great for a machine finished blade IMHO.

-Josh

I had not heard of soaking cork but it makes perfect sense.
I saw them used years ago with the green rouge in the Loveless shop but I just started using them a little over a year ago on my knives. I have been using the scotch brite type belts for a nice brush satin finish since I started and wanted to experiment with a finer finish without hand sanding.

Cork, and cork and rouge do give me a finer finish.

Laurence

www.rhinoknives.com
 

Frank Niro

KNIFE MAKER
Thanks for the water bath thing Josh. I still have a few old type 800 grit ones on hand. I'm going to try the stripping and green rouge thing again. I never did get that to work well .Once properly prepared I have been told a belt will last one very long time. Frank
 

Josh Dabney

Moderator
No problem

FWIW My experience mirrors others. The cork belts last and last. I don't use it all the time but I've got a 600 that's probably at least 3 years old.

-Josh
 

Frank Niro

KNIFE MAKER
I found a 1000 grit and put it in to soak. It was cork alright. It wanted to float. I took it out a few hours later but can't get back to it. Did you "turn your's down" while it was wet , Josh? I will go at it again tomorrow. I have one of those simple stone wheel truing giz moes I will try on it. I sure would love to get a polishing belt !!! Frank
 
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Josh Dabney

Moderator
Frank,

I did the initial break in by pushing a piece of 1080 barstock flat against the belt running full tilt for a few minutes. This more flattened down the cork than turned it smooth like you're thinking. It still has a coarse appearance in comparison to your typical belt.

I wouldn't attempt your giz moe just for fear of it tearing the cork up.

Keep in mind too that the abrasive is embedded in the cork so when the cork is rough in the beginning you may get a little bit of a streaky look from it. The smoother it gets the more even the finish will be.

-Josh
 

Frank Niro

KNIFE MAKER
I did get it down quite a bit with a hardened piece of metal, but I still didn't like the looks of it. What I did was did into my belts and come up with a ceramic 36. I placed a dowel inside the 36 and pushed it up against the moving cork. Even this look a few minutes and I had to keep moving the 36. I think it took several visible ware areas. I did put some green on it but no blades ready at this time to try it on. Frank
 

rhinoknives

Well-Known Member
Frank,
be careful here using the ceramic 36 grit belt. Yoou could imbed the ceramic in the cork and ruin it.

Cork are just a different kind of belt. It won't ever look even. Don't comcentrate on what the cork belt looks like?
Look to see the finish it will give you on harden steel.

Just trying to help.

Laurence

www.rhinoknives.com
 

Frank Niro

KNIFE MAKER
Laurence, I hope I haven't screwed this one up. It was the only 1000 I had. Do the ones you have developed give an actual polish ? Thanks Frank
 
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