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Etching is an ancient craft that's been practiced for centuries to produce beautifully decorated items, such as jewelry, weapons and armor. It's also a way to create designs on metal plates that can then be inked to print on paper or other materials.
Here are the basic steps required to etch metal.
Some chemicals used in the metal etching process are toxic. Protect your eyes with safety glasses, your hands with gloves, and your skin with an apron, long-sleeved shirt and long pants.
Etching chemicals typically produce dangerous fumes, so you may need to wear a protective mask and/or make sure there is enough airflow in the area. Be sure to follow the directions on any chemical packaging.
Prepare the metal surface
If etching a metal plate, file off any sharp edges.
Alcohol or a chlorine-based cleanser can be used to remove any oils. Prepare the metal surface to accept the resist by lightly sanding with fine sandpaper, steel wool, an abrasive plastic sponge or a wire brush. Make sure not to scratch the surface too deeply, which might affect the etched pattern, but aim for a slightly rough texture.
Rinse completely with water, then wipe with isopropyl alcohol.Browse Safety Products for your Project
Create your design
Traditional etching involves covering the metal plate with a resist made of wax or varnish. Next, the design is drawn by hand using sharp tools to scratch off the resist in every place where a dark line is desired. This leaves a pattern on the surface that is vulnerable to the etching action of the acid.
For a more modern version, use electrical tape, nail polish, or permanent markers to cover the parts of the surface that you want to remain light. Any area not covered will be etched in the acid. You could also use vinyl stencils or transfer paper to transfer a printed black and white design. After pressing on the design with a hot iron, the white parts will peel away, leaving the black ink on the surface, which will act as the resist.
If you are going to use the etched metal plate to make prints, the design will be reversed: The part covered with resist will remain light, while the parts that are etched will be inked.
Etch the design
If you are etching a plate, tape over the edges with masking tape to protect them from the acid. Immerse the object in a container ("bath") of the acid.
The type of metal you are etching will determine which type of chemical bath you should use. For example, steel can be etched with hydrochloric acid, nitric acid, or sulfuric acid. Copper can be etched with ferric chloride mixed in water to form weak hydrochloric acid. Soft aluminum can be etched with ferric chloride, using acrylic polymer paint as a resist.
The longer you leave the item in the bath, the deeper the pattern will etch. For printing plates, this means darker ink.
Clean the plate
Once the metal has etched to the desired depth, stop the etching action by washing the plate in water or using baking soda to neutralize the acid. Next, remove the resist, using an appropriate method or chemical. Use turpentine for varnish, alcohol to take off wax or permanent marker, or acetone to remove nail polish.
For more information about metals, contact the experts at Industrial Metal Supply.