The three countertop sections are out of the clamps and ready to prep for finish.
I want to finish the bottom of the sections just in case some moisture gets under there. I roughly cleaned up the bottom to make it flat and then started putting finish on it. Unfortunately about 5 minutes into the process I realized that as the end-grain was soaking up the finish, it was expanding and thus bowing the whole countertop. So, I turned them over and applied finish to the top as well. Of course, I hadn’t prepped the top or anything yet, but that did take care of the bowing. All that finish had to come back off later before final finish was applied.
I mounted each countertop section onto 3/4 plywood as a subbase to make the top appear thicker and also to provide support. The sections are cantilevered about 10″ and the plywood helps to stiffen them up so they don’t need additional support over the air.
I took the time to fill some cracks + voids with epoxy. Unfortunately it didn’t really seep down as well as I’d like, but it worked OK in spots. Maybe a bit overkill, but I’m glad I took the time to do it. I put some wax paper between the countertop and plywood so that epoxy wouldn’t permanently stick them together. By the way, the plywood base is inset about 1/4″ on all sides; the whole thing gets a border.
I started with the Festool RO125 and quickly realized it was going to take awhile to get the top all smooth and epoxy lines (from glue up) down. So, I reverted to the drum sander for a few passes. That still took quite awhile, but I think was faster overall. After working through grits up to 220 on the drum sander, I had to go back to 80 on the RO to get rid of the straight scratch marks left by the drum sander. I was surprised I had to go back so many grits, but the end grain really takes a scratch that’s hard to remove.
Finally the top is sanded through 220 with the RO and ready for finish.