by raimundo » 3 May 2010 7:23
3m wet or dri sandpaper has corundum grit. this is fixed to the paper with a glue, Used dry this grit will break off the paper and stay on the sanding stick for a while, breaking down into finer grit as it crushes against other corundum grit.
Norton sandpaper does not cut steel as well, even though it is black grit.
Wet sanding keeps the fine dust from going into the air, it creates a slurry of the grit that stays on the paper longer and will break down into finer grit so that you may believe that the wet process makes a better surface, but it works the same in wet or dry, the difference is dust control and that slurry.
If the grit is fixed to the paper with water soluable glue, the grit that is wet may readhere to other surfaces.
it does not take much water, only a few drops acually, in fact when I do it, I use spit. this has a different viscosity and will be less likely to spray off the sanding tool in fine drops. also its more efficient to apply.
Wake up and smell the Kafka!!!