Mugi-Urushi

This is the second article in my Kintsugi research series. For the overview, visit Kintsugi 101. Read on for instructions on how to join broken ceramic pieces together.

For my first project repairing a cracked bowl, I am using the following recipe for mugi-urushi:

  • 4 parts mochi rice flour
  • 1 part white wheat flour
  • water
  • seshime urushi from Mejiro

I mixed the flour and water to create a dough, then mixed 1:1 with urushi to create a paste. I applied this paste to the two halves of the bowl with a plastic spatula and squished them together without a waiting period.

Although Kintsugi Oxford recommends a wait period of 1 hour before pressing pieces together, Kintugi.com does not. I decided to follow my gut here and squish them together right away, since my previous attempt at sabi started hardening within the first 10 minutes.


💡 Important Lesson

Know your materials’ dry time in advance!


I use tofu boxes to swatch test ahead of time

For the undercoat (Shita-nuri), I’m pretty sure I bought the wrong type of lacquer. Seshime Pure Lacquer dries light brown, and it’s almost translucent, whereas Kintsugi Oxford and Kintugi.com show a black opaque lacquer. Plus, I found some sites referencing seshime urushi as a wood stain, which explains why it’s so thin. The buildable layers would look great on wood.

Even if seshime is the wrong type of lacquer, it still works to stick things together. So, after mixing and squishing, I wiped the excess mugi-urushi off with a spatula, positioned the cracks so they were seamless, and rubber banded the whole thing together.

Right after application, I wiped off the excess with a spatula and let it sit for 3 hours in the curing box.

This image looks a little wild because of all the spatula marks, but they come off easily with a little sandpaper and water.

After 3 hours, I sanded off the excess with wet sandpaper and used acetone to clean up the edges. I was concerned about chipping and breakage with the rice flour based on Kintsugi.com’s opinion that rice flour is less malleable and more brittle than wheat flour. However, rice glue feels more traditional, and I couldn’t stop thinking about an old TV special I saw about mashing mochi rice to create a glue, similar to this process. So, I gave it a shot, and so far it hasn’t broken.

Note the nice fill of a piece of chipped glaze
The bottom had another piece of chipped glaze that the mugi-urushi filled in nicely, despite my best efforts to sand it away. 🙂
This portion chipped and crumbled away during sanding, but that’s OK because I will fill it in with sabi during the next stage

Overall I’m very happy with this mugi-urushi recipe for this type of crack repair. The bowl is very lightweight, so that might have something to do with it. In the future if I work on a more heavyweight ceramic repair, I’ll probably increase the wheat flour ratio.

After 14 days of curing, I’ll continue to the sabi phase!

to be continued…