I finished the PO Box door bank I was making for our granddaughter (finished photos in the Box for everyone thread. But I mentioned I learned some painful lessons so thought I'd address those here:
1. The burl slices I used for the sides were 1/2" thick and seemed solid enough. But when I was cutting the finger joints I had some pretty bad tear outs and chipping. Not sure what I could do to prevent it, but I didn't expect it. I fixed it by mixing saw dust from the boards with Titebond and filling the chips and spaces. In some of the smaller spaces I simply filled the space with dry sawdust and then carefully dribbled extra thin super glue in, and repeated until the space was filled so I could sand it smooth again.
2. The burl slices were flat when I started. But by the time I finished cutting the finger joints, one side had warped a little. The result was the finger joints didn't line up precisely and I had to some sanding to get a decent fit. I didn't want to force the fit because I'd already had the chipping and worried the fingers might break completely off. Again, not a fatal flaw but something I didn't expect. I guess the burls are more susceptible to movement thru humidity. I also work out in the driveway so I guess the sun could be a factor too.
One other thing while on this topic. I wetted this warped side and stickered it on the bench with some weight on top and it flattened right out. Much easier than a regular grained board would have.
3. I was surprised by how dark the wipe-on-poly turned the burl boards. I still like the color, just surprised it darked them as much as it did. Lesson being to do a trial on a scrap piece or something, just in case you don't like the result. See photo.
4. This one nearly was a real bummer. My sides are nearly square. I was being very careful to rotate and flip the adjacent sides when cutting the fingers. BUT... I completely overlooked that I had rotate one side a quarter turn, so I started cutting the fingers on what should have been the top edge, instead of on the side. Luckily, I had enough box that I went back, cut the fingers in the appropriate side, and then, after gluing the sides together, simply sliced off about 3/8" from the top, removing the wayward fingers that weren't supposed to be there. I figured that was easier than cutting two 3/8" square pieces and carefully fitting them into those finger cuts to hide my mistake. So if your sides are nearly square, be extra careful you're cutting the side, and not the top or bottom edge.