Question: Oil contamination on waterstones

If you take a dry stone and drop some water on it, the stone should absorb it. If it beads up on the surface it has oil in it.

At least that's my understanding of it.
 
that is if the stone is completely soaked with oil. not for accidental contamination.

i had a couple of drops of oil on a 3k naniwa. i tried my best to avoid damages, dish soap with a brush, hot soapy water soak, flattening etc ... nothing worked the drops are still visible on the stone and don't work the same as the rest. they get black as soon as i pass a blade on it and feel "gummy" when sharpening. almost like there is some chewing gum on the stone. this has spread at an important thickness as the stone has probably been laped 10 times or more since the accident.

i'm lucky it's right at a corner. in the middle of the stone it would have bothered me a lot.
 
pwet said:
that is if the stone is completely soaked with oil. not for accidental contamination.

i had a couple of drops of oil on a 3k naniwa. i tried my best to avoid damages, dish soap with a brush, hot soapy water soak, flattening etc ... nothing worked the drops are still visible on the stone and don't work the same as the rest. they get black as soon as i pass a blade on it and feel "gummy" when sharpening. almost like there is some chewing gum on the stone. this has spread at an important thickness as the stone has probably been laped 10 times or more since the accident.

i'm lucky it's right at a corner. in the middle of the stone it would have bothered me a lot.
Click to expand...

Can you post pics of what those look like? I have some discoloration on my edge pro stones and I'm kinda worried that they might be oil contamination.
 
did you drop oil on the stone?

i've heard people mention boiling stones for 10-15 minutes to get the oil out, even adding some baking soda or soap to the water, but i have no first hand experience with that.
 
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singularity35 said:
Can you post pics of what those look like? I have some discoloration on my edge pro stones and I'm kinda worried that they might be oil contamination.
Click to expand...

here you go, when flattening the side i use i remembered why i didn't use the other side anymore ... it's because i have a way bigger oil spot right in the middle ... that's what you get when using waterstone in a busy pro kitchen. this will be more obvious and easier to let you see the result after sharpening.

tried my best to take decent pictures, i'm no photgraph

the two first picture are the freshly laped stone (with dmt XC)

p1000333r.jpg


p1000334op.jpg


then a picture after polishing a wide bevel (cheap but very good karesuando pukko i had in my kitchen drawer.) EDIT ooooops it's a Iisakki ...

p1000335l.jpg


here you can notice how the stone is naturaly darker where it has worn out from use compared to the part that i didn't use AND the lighter colored spots that became black from sharpening. this is only from a couple of strokes.

on a side note this pic shows what i LOVE with naniwa, they give you the brighter finish i've ever seen at each grit range ... this is 3k and you can already see me in the bevel in fact most of the scratches you see come from the previous stone used (a diafold probably F, i flattened the bevels just for fun this one as a microbevel) . 5K is almost scratchless 10 you have to search the scratches in the light ... the 3k stone with a good CrO loaded strop and a little patience yield a wonderfull mirror polish.
 
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