I just experienced the "too smooth" syndrome on some front porch columns I built up out of 2x pressure treated pine. I used, for the first time, Min-Wax epoxy filler to fill the knots etc. It sands glass smooth. I sanded the columns with 220 which on the PT was ok but on the filler made it too smooth. I was spraying latex primer with a bit of Floetrol added as a retarder. The paint took to the wood perfectly but slid right off the slick epoxy filler. I went back and resanded with 150 and reshot with the same paint mix and it game out great.
A brochure put out by Min-Wax on refinishing floors says: "Sand the floor for a third time with 100 grit sandpaper. If floors are not going to be stained, then follow this sanding with a final sanding using 120 grit sandpaper."
So smoother is not always better. Apparently the stain will not soak in as well if the wood is too smooth. |