You can cut the slab from a piece of felled lumber, or have a lumber mill do it for you. Choose wood that was felled during the summer. It will be easier to remove the bark later on. Knots, burls, and limbs often reveal surprising patterns and textures. Take these into consideration when picking your slab.
If you cut the slab yourself, or had a saw mill do it for you, air-dry or kiln-dry the slab first.
Work your way along the edge of the slab. If you work across it, you may gouge the surface and leave marks. Scrape the fibers off with a nylon or wire brush.
The flaps typically only have sandpaper on 1 side. Make sure that you are moving your rotary tool with these flaps facing forward. Don’t move the tool back-and-forth. How much you sand the edge is up to you. Lots of woods often have worm holes under the bark. You can sand these off or leave them on for a cool effect.
If you have a round slab, or a slab with bark on all 4 sides, you can skip this step.
You don’t need to finish sanding both the top and bottom faces.
You can flatten the bottom of the slab too for a nicer finish.
Butterfly keys are blocks of wood shaped like bowties. Use a block plane or a powder sander to trim the keys. Use a sanding block or sandpaper to sand the eyes. If there is a split in the underside of the slab, you should install butterfly keys too.
You are doing this after you sand the faces because some pieces of trapped bark may not get revealed until after you sand them.
You can also use plumber’s putty for this, but it can be difficult to remove–a quick blast from an air compressor hose ought to do the trick, however. If you choose to leave the voids hollow for a rustic look, skip past this entire section.
Test your epoxy on the voids on the underside of the slab. If you plan on tinting the epoxy, coat the wood with shellac first. This will prevent the epoxy from soaking into the wood and forming a “halo” of color.
If you have a lot of voids, it’s best to work in small batches, otherwise the epoxy will cure before you finish. Use enough epoxy so that it is level with the surface of the wood.
