I lapped and dressed my two Arkansas whetstones that I purchased from Dan's. The two stones: Black Arkansas (Ultra Fine), Hard Arkansas (Fine). They were not flat (especially the Hard Arkansas). I started by marking the surface that I was lapping with a red sharpie. I also put an arrow on the edge to point to the surface I was treating. I only lapped one side of each stone.
I purchased the "Small Rotary Grit Pack" from The Rock Shed. To lap the stones, I used 60-90 grit SiC powder, with water, on top of a steel cookie sheet, on top of the concrete garage floor. I lapped until the red markings were gone. Then I marked again and ran the stone over the grit to confirm it was flat. I continue with the 120-200 SiC powder and then the 500.
I switched to the w/d sandpaper. I had a spray bottle of soapy water. I sprayed the stone then rubbed the surface with the sandpaper. I started with 600 grit on both stones. Then on the Black Arkansas, I used 800 grit followed by 1000 grit.
One note regarding the cookie sheet. After a while it would bow up in the middle, so I had to press down to keep it flat. Eventually, I put a stack of ceramic pots on it to make it easier to hold down (reducing usable area but also reducing the amount of work). End-to-end it took a couple of hours. I would rinse out the cookie sheet and bucket of rinse water for every change in grit when using the SiC powder.
Final note, I had a hell of a time finding SiC powder in the grits that I wanted. My first order Cutting Edge Supply was a disaster (long story short, it took almost a month to get it, and then it wasn't what I ordered). The Rock Shed was much better and prompt. The grits they have didn't match what I wanted in all cases but was good enough. My order from Cutting Edge Supply was on 15-Nov and my order from The Rock Shed came in yesterday (20-Dec). The Rock Shed was good at getting the order in the mail, but it was "in the network" for a while before it finally emerged a couple of days ago.
I purchased the "Small Rotary Grit Pack" from The Rock Shed. To lap the stones, I used 60-90 grit SiC powder, with water, on top of a steel cookie sheet, on top of the concrete garage floor. I lapped until the red markings were gone. Then I marked again and ran the stone over the grit to confirm it was flat. I continue with the 120-200 SiC powder and then the 500.
I switched to the w/d sandpaper. I had a spray bottle of soapy water. I sprayed the stone then rubbed the surface with the sandpaper. I started with 600 grit on both stones. Then on the Black Arkansas, I used 800 grit followed by 1000 grit.
One note regarding the cookie sheet. After a while it would bow up in the middle, so I had to press down to keep it flat. Eventually, I put a stack of ceramic pots on it to make it easier to hold down (reducing usable area but also reducing the amount of work). End-to-end it took a couple of hours. I would rinse out the cookie sheet and bucket of rinse water for every change in grit when using the SiC powder.
Final note, I had a hell of a time finding SiC powder in the grits that I wanted. My first order Cutting Edge Supply was a disaster (long story short, it took almost a month to get it, and then it wasn't what I ordered). The Rock Shed was much better and prompt. The grits they have didn't match what I wanted in all cases but was good enough. My order from Cutting Edge Supply was on 15-Nov and my order from The Rock Shed came in yesterday (20-Dec). The Rock Shed was good at getting the order in the mail, but it was "in the network" for a while before it finally emerged a couple of days ago.