How to: Screen Printing on Galvanized Metal Sheets
Galvanized metal is steel covered in zinc oxide to protect it from exposure to the elements. The zinc acts as a barrier between any corrosive agents and the metal to prevent oxidization or corrosion. Silk screening is a type of print making that involves "burning"---through use of a type of photo emulsion---onto a screen and dragging water or acrylic-based paints across the image to print it onto a surface. It is generally difficult to paint on galvanized metal because most paints do not adhere well to the zinc. However, with some modification, silk screening your piece of galvanized metal is possible.
Things You'll Need
- Galvanized metal
- Metal primer
- Silk screen
- Photo emulsion
- Design printed or drawn on transparency paper
- Plastisol or acrylic-based silkscreen ink
- Silk screen squeegee
- High performance epoxy (optional)
Instructions
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1
Clean the surface of the metal sheet with soap, water, and the rough side of a sponge to make sure any dirt particles are removed from the sheet.
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2
Prime the metal surface with a primer specifically designed for galvanized metal. Apply an even coat with a paintbrush and allow ample time for the primer to dry. It is best to let the primer sit over night.
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3
Prepare your screen for printing. Set the photo emulsion on your screen over night. In the meantime, prepare your design. Many designers and artists use computer programs to create their designs, but you can also draw your image by hand. Print out or draw your design in black ink on transparency paper. Place the transparency in the center of the screen with the design facing down. Set the screen under a direct light to burn the image into the screen. Allow the screen to sit in the light for as long as the photo emulsion directions state.
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4
Rinse off your screen. Begin by removing the transparency and then run the screen under cool water. When the screen rinses clear in the places where the design was black, your screen is ready. Let the screen dry before attempting to print on the metal.
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5
Lay the screen flat on the galvanized metal. Pour a moderate amount of the plastisol on the bottom of the screen. Have someone hold the screen in place for you as you use the squeegee the pull the ink over the screen. When you have adequately coated the screen, carefully lift it off of the metal.
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6
Dry your print. You can either let the print sit overnight to dry or you can use a fan to help speed the drying process.
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7
Paint a topcoat of high performance epoxy over the print if the piece will be left outside and exposed to the elements. If not, this step is not necessary.
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