A friend gave me this bowl to repair, and it sat in my shop for years before I got to
it. Then, it took me some time to figure out what to do. Borrowing somewhat loosely from
the Japanese art of kintsugi, I decided to fill the cracks with a mixture of FDA-approved
epoxy and walnut shells. There is no way this bowl will look like one piece again, so I
strove to make the repair aesthetic in its obviousness.
When I got the bowl, it was in one piece. To remove as much of the old shellac as
possible, I wrapped the bowl in paper towels soaked with alcohol. I then discovered an
original repair along the crack because the original glue let go after exposure to so much
alcohol. Now I had two pieces! This actually made the repair easier since I didn't have
to sneak into a crack.
There was a second radial crack that I sawed out. I first thought that filling that
slot with a solid piece of wood made the most sense, but changed my mind to fill it with
epoxy/shells. To strengthen the edges, I put a block spanning each gap along the rim. To
remove the stress riser at the end of the slot, I put in a round plug. Carving the patches
was easy, and I left them looking carved.
The epoxying was a royal pain. Masking the bowl took easily an hour, and still leaked
out the other side. The epoxy I chose due to it being food-grade* has a long open time and
flows slowly but surely for most of that time. In fact, it's designed to flow. It's also
sticky and the walnut shell pieces stick to the bit of wood I used to shove them around
and into the crack. It took patience and perseverence to herd the little bits into
place. To reduce waste, I put the unused portion in the freezer then thawed it back out
with my heat gun. If I hadn't, I would've thrown away 3-4 times more than I used. Filling
the round surface took multiple sessions, or the epoxy would've just run away. With my
basement chilly in the winter, I resorted to a heat gun and pad to warm the bowl so the
epoxy would set.
The wood of the bowl is not one I'm familiar with. It could be beech, and is too dark
and not hard enough to be maple. It's unlikely it's walnut. The edge blocks I added are
Norway maple, from a tree I used to have in my yard. The pale maple of the repair
contrasts nicely with the original wood.
As for the finish, I looked around at commercial finishes that claim to be food safe,
and was not at all impressed, to say the least. One popular "salad bowl finish" is a
urethane, which they claim "food safe when cured", including the quotation marks. Pah. Not
in my book. So, I decided to go back to the old times and used flax oil (aka linseed
oil). I can buy food-grade flax oil at my local store, so I did. I also mixed approx. 4
parts oil to 1 part beeswax to use as a top coat. The bowl got two coats of straight flax
oil, which it sucked up greedily, then two coats of wax/oil. This finish is not very
durable, but it is completely edible and is very easy to maintain.
*Some will question the food-grade status of the epoxy. The FDA has approved it, but it
is bis-phenol A. It was the only epoxy I could find rated for food contact. Most epoxies
are far worse.