M A R B L E D   L E A T H E R   B O W L 

In the summer of 2018, I became very interested in materials that have color changing properties or have the capability to manipulate the eye to see different colors
based on light and context. I wanted to make a bowl from some pieces of leather and the liquid crystal I had on hand.

When I think of bowls, I’m inspired by kintsugi and marbled ceramics. Kintsugi is the Japanese art of repairing broken pottery with gold lacquer. I like the notion of
seeing beauty in imperfection, and find the natural lines of marble elegant and sophisticated.

I did a quick Youtube search, and went down a rabbit hole of marbling tutorials, including suminagashi, the Japanese art of paper marbling. I learned that it is
possible to marble textiles, so I decided to try with leather. 

I always begin my projects with materials research and testing :

I wanted the bowl to be water resistant so I studied my material properties and conducted a 1 minute water test.

I only had three sheets of leather (300mm x 300mm) on hand. At .7mm thickness, layering two pieces together doesn’t provide enough strength or structure to
support a cup of water. I looked to the materials I had on hand and landed on kraft paper. It’s often used as an alternative to leather to make wallets and bags
because it’s made from 100% wood pulp and is biodegradable. The one I have has a waterproof coating on one side and is stiff enough to provide structure. It is  
also tear-resistant, moldable and washable.

I bought a marbling kit and gathered all my supplies to begin marbling for the first time : 


First, it’s necessary to mix a mordant for the marbled design to adhere to the leather quickly and permanently. Mix 2 teaspoons of aluminum sulphate to one gallon
of warm water, and soak the leather for 20 minutes. Hang dry. After it is dry, steam iron the leather at a low setting. Next, I prepared the marbling base by mixing
carrageenan, a natural seaweed derivative. Blend 2 tablespoons per gallon of warm water and whisk until it disperses. Let rest until there are no more clumps.

While I waited for the marbling base to dissolve, I made a mold from a cork bowl I found at a store. This was a lucky find becausethe shape and dimensions matched
what I had in mind for the bowl. Initially, I planned on cutting a block of wood and sanding down the corners myself, but this made my life a whole lot easier :

I got a sheet of ¼” plywood and measured out the cuts I would make with the bandsaw to add ¼” height to the bowl, a base for the mold, and some rectangular
pieces to use as spacers between the mold and clamps so the clamps don’t leave an imprint in the mold.

I used a sander to round out the corners, gaffer tape to smooth out the sides, and wood glue to attach the mold to the base, and clamped it down.
The glue usually sets in about a half hour, but I left it clamped while I went on to marble the leather.

An element of surprise I wanted to add is marbling the leather with liquid crystal.

Liquid crystal are temperature sensitive compounds that temporarily change color with exposure to heat. Liquid crystal can be found in mood rings to LCD screens.
I had a vial from when I was researching how to make my own LCD screens over the summer. According to its product description, it has a 12 color range between
60 - 90F. Our normal body temperature is 97.8-99.3F.

What I like about liquid crystal is that it goes on clear, so it doesn’t distract from the marbled matte surface. I like that it’s subtle and I think it’s fun.

Touching the bowl with warm hands or hovering a blow dryer over it allows you see the color change effectively.

After marbling the leather, I measured the dimensions of the mold to draft a pattern for the bowl. Pictured below is the pattern for the kraft paper layer. As you can
see in the center line, it is on fold so it has more weight and the waterproof coating is on both sides. I marked the rubber feet placement and left allowance on all
sides to fold into themselves to create a sturdy top edge for the bowl.

In the first photo below, you can see the first prototype. I drafted and cut another and clamped it for some time over the mold to keep its shape. Then I wet the
leathers, went over to the ironing table to steam iron the marbled leathers, then treated the leather with mink oil liquid to soften and waterproof the leather.

I took the kraft paper off the mold to begin molding the leather face down onto the mold to serve as the interior of the bowl. After that, I stacked the kraft paper
layer over it, and began molding the second piece of leather face up over them both to serve as the exterior of the bowl. I marked the rubber feet placement,
punctured the holes to put them in, and clamped all three layers, on all sides overnight. The next day, I cut away the top edge excess, sanded it down, and finished
the edge with a styling type. 

The final result! The bowl changes color when touched!