Copper, A friend of the Craftsman

August 15, 2018Sharewoodworking

Copper, due to its texture and easy applications, seems to be the perfect natural metal for craftsmen and other workers to work with. Unlike other metals that do not go well together with wood, copper supplements the beauty and natural appearance of wood because of its own unique color.

During the arts and crafts era early in the century, copper gained roaring fame being the first metal to be processed by the human hands. The era was marked by a genuine effort to introduce copper into the mainstream building and construction industry. The use of wood and copper together formed the base of home, furnishing and other hand-wrought products.

Cutting Copper

So, when time came to do some research work on the project, we decided to move forward with this beautiful and shining metal. After some tests and trials, we were ready to give the worn-out old aged copper some new modern looks that would bring it up to date with the new designs in the arts industry.

Although copper is sold on many fronts and in many forms, the best way to get copper for handcrafting is going to a specific shop that deals in craft work and asking for copper sheets. Copper is also found in a number of alloys and metal combinations. It is important to pick a form that is pliable and soft to work with. Once you have got the right material, you can move forward by marking lines on the sheets for cutting, preferably by a scribble or awl because pen ink and pencil do not adhere well on pencil sheets.

Avoid using markers too, they form lines that are too wide for precise metal cutting and may result in inaccuracy that may sabotage the whole experiment. For marking the lines, use a ruler that is not only straight-edged but also does not skid. (If you cannot find the perfect ruler, put some tape on one side of the ruler and rub it against a piece of cloth to make it firm).

For scribing curving and bending lines, use a French template which is also properly skid-proofed prior to the drawing. If you want to cast more complicated designs on the copper sheet, paint-spray the pattern or design directly on the copper and cut them carefully. For this kind of cutting, tin snips are the preferred choice for cutters, provided the copper sheet is not thicker than 1/32 of an inch. During cutting, remember not to close the fingers of the snips completely. This will prevent the edges of the sheet from crimping when the jaws of the snips collide.

Also, make sure that most of the cutting is done by jaws open and small cuts. If tin-snips are not available, they can be substituted by jigsaws, band-saws and scroll-saws. When all the work is done and it is time for power sawing, attach a quarter inch scrap-wood to the back of the metal. If you are going for a few scroll-saw cuts, use a number 5 blade (.038x.015″ with 16 teeth per inch). Heavy copper sawing requires a metal slicing blade that has at least 24-48 teeth per inch and is also carefully lubricated using beeswax.

There is a lot of technique in using saw for metal cutting. For instance a variable-speed saw must be operated at slow pace for metal slicing. As for the band-saw and jigsaw, 14 teeth per inch general cutting blade might be used. If you proceed with cutting the copper with a jigsaw, start by clipping the sheet carefully to the work-plate with the area to be cut parallel hanging over the edge. The base area of the saw must be covered with mask tape to prevent the copper from getting scratched.

To make sure that your copper sheet has been cut in the most precise and smooth way possible, clamp the metal sheet in between two pieces of scrap-wood. To prevent the finish product from getting spoiled, bring out the edges of the metal above the wood for about 1/16 of an inch, as shown in the figure and mark a line along the edge. Also if required, mark and drill holes before finishing up.

Antiquating Copper

Craftsmen overtime have used specific techniques and methods to give copper the antiquated look. One particular technique that is still used by artists is based on dissolving copper in a suspension of potassium sulfide and water. But according to Dr. Jim Lindberg of the Drake University, this method creates danger as the solution of sulfur and water produces a gas known as hydrogen sulfide (H2S) which is almost as toxic as Cyanide.

The professor also warns that without proper ventilation, the gas might be life-threatening. This threat forced us to look for new ways to age copper. Our search brought us to a common photographic chemical known as rapid fixer. The product is easily available in most camera stores as well as their supply stores (We used the common Ilford Universal fixer).

The process of aging starts with cleaning and rinsing the copper to rinse it off of the unwanted oil and dirt by using your everyday kitchen cleaner. Then use a smooth satin silk to sand the open side of the sheet with a scotchbrite pad following a gray ultrafine pad. To avoid casting fingerprints on the copper, use gloves or handle the sheets with perfect care (for our experiment, we used latex gloves and used the edges of the sheet to move it around). This is followed by washing off the sand remainder (we used denatured alcohol for the process).

For diluting the rapid fixer, use a measured funnel, pour the rapid fixer first followed by water in the ratio 1:2 mixing it properly. The mixture will then go into a satisfactory tray (we used the ordinary photo-developing tray). The next step comprises of sliding the copper sheet with its face up into the tray and shaking the tray lightly so that the mixture completely covers the surface of the copper. After a while, the copper starts getting tanner. The color we are looking for is roughly the texture of cinnamon (which might take about 10 minutes).

After you’ve got the desired color, remove the copper from the tray and rinse both surfaces with running water. You can dry the sheet by hanging it by its edge or by the use of hair dryers etc. If the copper looks like what you wanted it to look like after drying, use lacquer or acrylic for coating, if not, start the process all over.

Next Post