Spalted Birch Bowl - March, 2011

A friend gave me a segment of birch log some time ago.  I got a strange look when I got so excited at the fact that there was mold growing on the ends.  Took about forever to cut up with hand saws, and I blew up the first blank 3 times, finally managing to salvage a saucer out of it.  I figured out what I was doing wrong and turned the second one to about an inch thick.  I soaked it in denatured alcohol, then wrapped the outside in brown paper and let it dry for about a month - it was then bone dry.

After re-turning it, I was very pleased.  It was a consitent 1/4" thick all the way down the side and had the absolute best finish I've ever put on a piece of wood.

I went to turn the bottom off and ran into a problem - my cole jaws weren't big enough to fit around the outside rim.  No big deal - just bring up the tailstock and use the cole jaws on the inside, expanding just enough to grab and turn the bowl.  Worked perfectly... until I turned on the lathe.  Before touching the bottom with the gouge, I heard a popping sound and my heart sunk - the bowl had cracked down the side!

After considering my options, I ended up gluing it together with cyanoacrylate.  It went back on the lathe and I sanded for about 728 hours one Sunday afternoon to remove the excess glue and staining.  The finish was back to being nearly perfect and the crack barely visible, even though the bottom of the side is a little on the thin side.  (You can see light showing through some areas in places in the pictures.)

Now to get the bottom tenon off.  I built a donut chuck out of some scrap plywood and mounted the bowl in it.  (I'll most likely post on this in the future.)  It's something that I've been meaning to make for quite a while, but always put it off.  This chuck allowed me to access the bottom of the bowl and remove the tenon used to grip it during shaping/sanding.  I recessed the bottom about 1/8" so it sits on a narrow ring and added an extra reverse curve near the bottom.  I then sanded the whole thing as smooth as the rest.

It's finished with a coat of boiled linseed oil, then several coats of wipe-on polyurethane.  I sanded between each coat with a scotch-brite pad, the equivalent of about 400-grit sandpaper.  Carnuba wax was then applied with another scotch-brite pad, wiped off, then another coat of wax applied.  After it hardened, I buffed it by hand with a paper towel.  It's exceptionally smooth and has a satin finish.

The best part of all is that the crack which I spent so much time trying to repair to be as nondescript as possible is all but invisble.  Even knowing exactly where it is, the light has to be perfect in order for me to be able to see it.  As soon as the BLO went on, the crack basically disappeared!

This is one of my favorites of all the bowls I've turned.