A perculiar issue.

[Laurens]

This is my DMT stone. Since I started lapping my 1k naniwa there remains a green tinge to the plate. I wash the plate always after lapping. Has anyone had this happen to them? I wash the stone and have tried rubbing the residue off but no success. Perhaps I should soak it in something??

 

[Sxot]

Does the colouring seem to be a problem? I wouldn't have thought so.

 

[Havachat45]

I doubt it would be a problem unless it is transferring to other stones - just my $0.02

 

[Sxot]

I've been watching my ATOMA 400 since @Laurens posted this. I wash it off straight away and It has not retained the colour. I do notice the colour stain other things that aren't washed such as the stone holder.

 

[littleaussiebleeder]

It's just possible that the water @Laurens is using is a factor here. Hard, soft river, bore, even rainwater from tanks can contain chemical "impurities" which could affect impurities in the stone. People often think rainwater tanks supply "pure" water... but they forget bird, bat and possum droppings that often find their way into the tanks, not to mention stuff like jet fuel, dust and industrial other pollution that come with rain. As an old knife-maker, I have been sharpening blades for over fifty years and staining of whetstones and honing stones as described above is not a rare phenomenon. Even pollution or dust or stuff from grinders and sanders in our sheds can be the culprit. For that reason, knife-makers invariably keep their stones in appropriate covered boxes inside cupboards.