As promised, I follow up on this broken stone, hoping that i may be helpful to others.
First, after looking more carefully at the stone I noticed that there was another point where the stone was starting to break appart
Anyway, I tried to do my best to fix all that.
Step 1: sealing the bottom
I sealed the bottom parts of the stones with shellac. (5 layers). Very simple: use latex gloves and and respect the drying time between layers.
Step 2: find a good base
In my pile of useless crap that I keep, I noticed that I had a piece of slate coming from a roof. I thought it could be a perfect base for the stone. I cut it to shape using a trowel (see below this great youtube video to know everything about cutting slate without dedicated tools tools
[video=youtube;hjFyiq0Eiwo]https://www.youtube.com/watch?v=hjFyiq0Eiwo&t=21s[/video]
Step 3: attach the stone pieces to the base
I glued the stone slate. I did not used epoxy because I wanted to avoid bisphenol-A (contained in epoxy). I used a all around glue (TurboFlex 4 in 1). Working fast I glued the stone to the slate, put wises and waited.
Step 4: reinforce the cracks
Then I apply a not too thick layer of the glue on the sides where the cracks were. The idea was to make a layer outside of the stone that hold together the broken part without being problematic when sharpening or polishing. Anyway, when using the stone ones usually «removes» the corners, so I knew that the hardened glue will never be in contact with the blades.
Step 5: sealing (shellac, 5 layers)
Step 6: lap the stone
Finally I laped the stone to remove the big chips. That was maybe the most demanding part. Seeing that I was getting nowhere with my Atoma, I used the pavement in front of my flat on a rainy day. Neighbours must have bought I was crazyMaybe they were right. It worked like a charm. Finally, I smoothed the stone with an Atoma 400 then Atoma 1200.
- Et Voilà.
Step 7: try and enjoy
Total price: 9 euros (the price of the glue)--considering I already had shellac at home. Was ii worth the time? I let you judge. Here is a the results after a 10 min polishing on a well prepared knife.