Our knife sharpening machine has a wet wheel. It turns slowly in water bath which keeps the metal on your knife cool. No sparks are put off and it is perfectly safe. It will not ruin the temper of the metal. This is how knives are manufactured . Knives have been sharpened this way for hundreds of years.
My process should not be confused with grinding on a dry fast wheel.
If you have any questions about this feel free to contact me.