Chapter III: How to Make a Copper Bowl

Here are the tools and the material that we need to make our first piece of work:

_Material:_ 1 Sheet of copper, 20 gauge. Powdered pumice stone.

_Tools:_ Hard wood block, dividers, shears, round headed hammer, planishing hammer, round top stake, mallet, files.

_Directions:_ Take the sheet of copper, and with the dividers mark on the copper a circle having a diameter a little longer than the contour of your bowl design. Cut this circle out with your shears.

With the round headed hammer, using the rounded end, beat the metal disc into the hollow of the wooden block until it takes on a fairly even bowl shape. Keep turning the metal with the left hand while you hammer it with the right.

You soon have a rough shaped bowl full of bumps and wrinkles around the outer edge.

These wrinkles must come because the circumference of the metal disc decreases as it takes on the bowl shape. So long as these wrinkles are long regular curves, they will work out all right. If they should take short, sharp shapes there is danger of the metal splitting. In order to avoid this be sure to keep the wrinkles hammered out flat as you work along.

If you went on hammering too long after your bowl is shaped, the bowl would crack or perhaps break, for hammering leaves copper hard and springy. So you must soften it before you can safely hammer any more. To do this I hold the bowl over a gas range until it is red all over, then I plunge it into cold water. This heating to soften up the copper is called annealing. Repeat the hammering until the bowl takes on the shape of the design.

Now take your round top stake and put it into the vise. Place the bowl over the round top stake, and with the planishing hammer, beat the surface until it is perfectly smooth, driving the metal just hard enough to flatten the bumps made by the hammering in the wooden block. If carefully done the surface will be true and bright and covered over with brilliant facets. A skillful hammer-man can really drive the metal in any direction he may wish. In this way you make a bowl out of one piece of copper. The top of the bowl will be ragged. Cut this rough edge with a pair of shears. File the top with a smooth file until it is perfectly true. A good test to make sure of this is to lay the bowl down on a plate of glass, or hold it up against the window pane. If there are still any tiny openings left in the edge the light will be easily seen through them. More filing must be done until no light comes through from the smallest space. This done, take a piece of emery cloth and rub the edge of the bowl until the file marks disappear. If you lap the cloth over the edge your rubbing will leave a rounded edge, which is just the finish it should have.

_To flatten the bottom of a bowl:_ Turn the bowl upside down on a bench. With a pair of dividers find the centre of the bottom of the bowl. This is done by placing one leg of the dividers against the side of the bowl and with the other making a light scratch as near the centre as you can. Change the position of the dividers to the opposite side and do the same, but be careful that the scratch is light. Repeat this until you have done it on the four sides.

Where these lines cross is the centre. With one leg of the dividers on the centre draw a circle having a diameter of about two inches. Take a wooden mallet and strike down on the centre of the circle. This will flatten the bottom. Work from both sides of the circle and keep the rounding edge just touching the circle made by the dividers. If the strokes are too heavy the bottom will bend in like the dotted lines in the sketch.

In that case, turn the bowl up and hammer from the inside. The bowl is now ready for polishing. Mix some powdered pumice stone with water. With a woollen cloth that has been wet and then dipped into the mixture, rub the bowl. This both cleans and polishes and at the same time gives a beautiful lustre to the surface of the metal.