How to get a black piano-like finish
Posted on May 5, 2018Advanced Practices in Video, Performance and Electronic Arts
While I was working on Zutorie, I was aiming for the body of the piece to be piano-black. Once people saw the results of my kinetic sculptures, they were wondering how I did it and suggested I shared my process.
Keep in mind that the following steps were applied to Russian birch plywood. If you use other wood, you may need to do some tests beforehand.
Sanding, spritzing, and sanding
The first thing to do is to sand the wood. The plywood I picked was already somewhat smooth, so I started with a 150 grit sandpaper.
If I were to stain the wood at this point, the ink soaking into the wood would cause all sorts of little hairs to rise, undoing the sanding. Instead, I spritzed the wood with water with a small water spray.
Once the wood was dry again and all those little hairs were visible, I then sanded it again, this time with a 220 grit sandpaper.
Staining the wood black
While consulting with technicians and during my research, I stumbled on a useful article in the Lee Valley catalog about staining guitars.
It turns out that while a lot of instrument makers fetishize certain inks, regular India ink can do the trick. I used Speedball black India ink.
Spray the ink generously on the wood, and wipe the wood with a cloth. I kept wiping as long as there was some liquid ink still floating on the wood.
I sprayed two or three times right away, not really waiting for the layers to dry between each spray, and the wood turned a nice pitch black.
Finally, applying varnish. The Concordia Wood Shop technician suggested I look into using General Finishes varnish, which I used often to repair antiques. In Montréal, only the Circa 1850 store on St. Patrick street carries this brand.
Originally, I tested with a satin finish—shown in the picture above—but for Zutorie, I used a glossy finish.
It is suggested to apply three layers of varnish. Layers should be applied generously, but not too much if you want to avoid a plasticky look and feel. The photo above shows an overly generous amount applied.
Take a high quality brush, to avoid loose hairs during the application. Dip the brush generously, and hold it almost parallel to the surface onto which the varnish is applied. Do not brush too much if you want to a avoid brush strokes as the varnish dries.
Try as much as possible to avoid bubbles, both on the brush and on the surface. You could vibrate varnish pot, a bit like how baristas tap the milk on their counter, to remove the bubbles before dipping the brush.
Between each application, wipe bubbles and unevenness away with a 400 grid sandpaper. Don’t scrub too hard, sanding is not mean to remove the varnish. Do not scrub after the last layer has dried.
On the left is the result of the varnish with a satin finish, with an overly generous application for three layers. Some imperfections show because there were dust mites and bubbles still as I was testing.
On the right is the result on Zutorie, three layers of varnish with a glossy finish. In that case, some brush strokes are visible, but because the layers were less thick, you can see more of the wood grain.
Both were inked with the same ink, the color difference is really due to the different lighting and the cameras used.