First you need an Urushi box

The urushi box is not just a drying area – it is a key element in the traditional Kintsugi process . Unlike other glues that dry by evaporation, urushi paste (varnish) requires moisture and heat to polymerize properly . If conditions are not right, the varnish can remain sticky or even dry too quickly and become brittle.

How does the urushi box help?

Maintains high humidity – allows the varnish to cure properly.

Regulates temperature – prevents too rapid drying which can cause cracks in joints. Protects against dust and dirt – ensures clean joints and a smooth surface.

Using an urushi box ensures longevity and strength of the joints , which is essential for a successful Kintsugi repair.

Preparing a broken plate

Before I could start putting it together, it was important to properly prepare the plate.

Key preparation steps:

Surface cleaning – removing dust and small debris from the edges of cracks.

Edge beveling – lightly sanding the edges to make the joint stronger and more natural.

Putting the parts together – testing the joints to ensure everything fits perfectly before applying the glue.

- Why is this step important? If the plate is not prepared properly, the joints may be too weak or irregular, which can cause additional breakage during the repair.

Preparing the Mugi-Urushi mass

I mixed the urushi paste with fine wheat flour until I had a homogeneous paste. The mixture should be thick, but smooth and stretchy , to allow for a strong bond between the parts. I left it for a few minutes to bond , as applying it too quickly can weaken the bond.

Joining plates with Mugi-urushi paste

I protected the unglazed parts around the break with protective paper tape, so that they would not absorb too much pigment from the urushi paste. Mugi-urushi paste is applied to the edges of the cracks in a thin layer.

I used a thin bamboo spatula that came in the package along with the Urushi paste.

I put the parts together and pressed them lightly .

The plate goes into the Urushi box.

I placed the plate in an urushi box on a soft surface lined with plastic to retain moisture.

We maintain humidity in the box using a damp cloth or a small bowl of water.

The item being repaired remains in the Urushi box for at least 7 days.

🔜 In the next blog I will describe the preparation for applying gold.