Thread: Slurry Edge Dulling, Convexing and Micro Chipping

Thank you, and I think I follow, that with too dense a slurry while the trailing edge of the bevel is held in contact with the stone by manual pressure, the leading edge itself is lifted out of contact and this is exacerbated as the water content evaporates off the surface of the stone, resulting in a bowing of the bevel?

Almost, it is not uncommon for folks to have issues of harsh edges, when honing on clear water, to blame the stone for chipping the edge, a common complaint on Jnats and Coticules.

When honing on natural stones, using slurry is common. One begins with a thick-ish slurry and thins the slurry to clear water, no slurry. But often when honing on clear water, edge chipping occurs and the honer blames the stone.

Recently in another forum a honer made the same complaint and sold the pricy new stone. The new owner, said he was able to get very nice shaveable edges from the stone without issue. It was not the stone, but technique that was the problem. But why did that happen?

It may be the edge is convexed and then breaks off, after flexing on the hard-flat stone, so the issue is not the stone but technique, possibly slurry convexing and possibly swarf, beating the edge.

Alex, theorizes that a thick slurry can abrade the edge, more than the bevel (edge leading) and cause micro convexing at the edge. So that when, the same bevel and edge is/are honed, on plain water and a hard stone, the edge may not contact the stone, preventing the stone from cutting the fin/edge, off cleanly to form a straight edge.

If that is so, excessive honing on slurry, on an aggressive stone/slurry will have a lot of swarf, in front of and under the bevel. So, you can have, a convexed edge and excessive swarf, further keeping the edge off the stone.

Alex’s theory is the possibility of convexing of the edge, I am asking if you add the swarf shown in the micrographs, would that not exacerbate, the issue of convexing, and edge dulling, or at least keep the edge off the stone, preventing it from honing the edge, and then the edge breaks off?

On natural stones that use slurry, the practice of honing on slurry excessively, to break down slurry is common, this practice can cause both issues, convexing and dulling from swarf.

A simple solution is to make new slurry to finish and not keep working the slurry loaded swarf and use a progression of finer/thinner slurry.

Got it, thank you.