Thread: Finishing Stone Question

Does anyone see any issues with using a flattening stone on this guy? Seems a bit warped, and there's weird discoloration happening. Stone is completely smooth to the touch.

Hard to say from the pic. Remove it from the box and spray it with oven cleaner to remove the bulk of the crud, scrub with a stiff brush.

A long soak in Simple Green or any good degreaser 50 percent solution will get it clean. May need to soak for days, weeks or months if it is very greasy.

It looks large and possibly an Arkansas stone. If so, only loose Silicon Carbide will get it flat, start with 60 grit. There are many posts on lapping Novaculites.

Some better photos after cleaning may help identifying it.

Originally Posted by Euclid440

Hard to say from the pic. Remove it from the box and spray it with oven cleaner to remove the bulk of the crud, scrub with a stiff brush.

A long soak in Simple Green or any good degreaser 50 percent solution will get it clean. May need to soak for days, weeks or months if it is very greasy.

It looks large and possibly an Arkansas stone. If so, only loose Silicon Carbide will get it flat, start with 60 grit. There are many posts on lapping Novaculites.

Some better photos after cleaning may help identifying it.

I started to use a Norton flattening stone on it - the "crud" part is actually what's underneath. The more I flatten it, the more of the solid gray goes away and the more of that "rusty crud" starts to show. It's all super smooth though. Not greasy at all to the touch.

Originally Posted by Euclid440

Hard to say from the pic. Remove it from the box and spray it with oven cleaner to remove the bulk of the crud, scrub with a stiff brush.

A long soak in Simple Green or any good degreaser 50 percent solution will get it clean. May need to soak for days, weeks or months if it is very greasy.

It looks large and possibly an Arkansas stone. If so, only loose Silicon Carbide will get it flat, start with 60 grit. There are many posts on lapping Novaculites.

Some better photos after cleaning may help identifying it.

I second that, Silicone carbide powder has saved me so much time, just make sure to clean the stone and lapping surface 100 percent before moving on to the next grit, Im sure that would be covered in video.

Using a lapping plate on coties can be done but it will ruin a lapping plate as the cotieis so damned hard. Sounds like the color is coming thru more so a cleaning should be done. Grease and oils get down in the stone and can feel smooth to the touch. It wouldnt hurt to cleaning it.

Looks like a washita

I'd agree with it looking like a Washita. But still needs a good scrubbing, before its definable. If it is, you have a very versatile stone.

Having just done this, what worked for me was a week long soak in a degreaser (Simple Green). Heatied the solution and put the stone in just off boil at the start, followed by a good scrub with a nylon scrub pad, then back in for a soak at room temp.

Access to an ultrasonic tub would of course be better... I didn't have that...

Oven cleaner will remove the bulk of the surface crud, then soak for a day in Simple Green or any good degreaser. That will tell you if it needs more.

Most of these stones were used for years with oil and the oil has penetrated deep into the stone. They may not feel greasy but once soaked in degreaser or hot water will release oil. Often the oil becomes rancid and smell something awful, which is the reason I soak them.

Lapping a hard stone is some work that will require fresh hard abrasive, the Norton lapping stone will not flatten an Arkansas stone or any Novaculite, they are just too hard.

You can buy a progression of loose Silicone Carbide grits from 60 – 500 from Got Grit.com for about $15. You will use more of the 60 grit to get flat, after that the other grits go quickly. You will have enough grit to do several stones. Lap on a steel cookie sheet, on a teaspoon of grit and a bit of water, add grit as needed, mark a grid on your stone with a sharpie.

Originally Posted by Gasman

Using a lapping plate on coties can be done but it will ruin a lapping plate as the cotieis so damned hard. Sounds like the color is coming thru more so a cleaning should be done. Grease and oils get down in the stone and can feel smooth to the touch. It wouldnt hurt to cleaning it.

Originally Posted by Mikeinri

Looks like a washita

Originally Posted by outback

I'd agree with it looking like a Washita. But still needs a good scrubbing, before its definable. If it is, you have a very versatile stone.

Originally Posted by Euclid440

Oven cleaner will remove the bulk of the surface crud, then soak for a day in Simple Green or any good degreaser. That will tell you if it needs more.

Most of these stones were used for years with oil and the oil has penetrated deep into the stone. They may not feel greasy but once soaked in degreaser or hot water will release oil. Often the oil becomes rancid and smell something awful, which is the reason I soak them.

Lapping a hard stone is some work that will require fresh hard abrasive, the Norton lapping stone will not flatten an Arkansas stone or any Novaculite, they are just too hard.

You can buy a progression of loose Silicone Carbide grits from 60 – 500 from Got Grit.com for about $15. You will use more of the 60 grit to get flat, after that the other grits go quickly. You will have enough grit to do several stones. Lap on a steel cookie sheet, on a teaspoon of grit and a bit of water, add grit as needed, mark a grid on your stone with a sharpie.

I spent a bit of time cleaning it up. Here's what it looks like now:



You can see at the very bottom left the area that my flattening stone started to hit. Looks like I could spend a little more time cleaning it?

Also - there are some spots on my flattening stone that are started to feel pretty smooth. I assume I should abort using this stone and find something more coarse?