Album: Photos:BowlRepair

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.

Broken piece pinned in place (another view) Copper wires as pins Test piece for the filler
Edge blocks for strength Fitted! Glued in place! Carving the edge blocks
Carved! Ready for a plug Bottom view Glued!
Another edge block Ready for glue! Glued and carved! Carved!
Carve the plug Carving inside The only way to hold this thing Carved!
Almost ready for epoxy fill Slot inside taped Slot outside taped Crack taped
Mixing the potion Fill 'er up! Not full on purpose Partway
Fill the outside Filling the crack Crack all filled On a heating pad to cure
Cured and untaped Bottom view Start trimming Trimmed and sanded
Needs more epoxy Taped and tilted Oiling up! All done!
All photos Copyright Brian A. Whaley. All rights reserved.
Photo album generated by album a tool by David Ljung on Sat May 4 13:09:08 2024