The slab was mostly flat to begin with. However, it was fairly close to the center of the tree, and there was a bit of pith that cupped down the middle – about 1/4” high on one side and 1/4” low on the other.
A scrub plan likely would have made quick work of getting it roughly flat, but I don’t have a scrub plane. A planer would have been very effective as well, but it’s too wide for my 12.5” lunchbox planer. So instead, I took a a hand held belt sander to it for about half an hour to get it close. Then I ran it through my 16/32 drum sander. My sander is pretty weak, and bogs down quickly, so I estimate that the last 1/16th took 30-40 passes to smooth everything out. After that, I hit it with the ROS up to 180 grit.
Here’s a shots of the slab after the first coat of Tung Oil:
And here’s a closeup that shows just a little bit of curl. The voids are filled with a mixture of epoxy and sanding dust. I had a lot of sanding dust.
I got most of the base done last night, but that will need to wait for the next blog.