Enameling on Steel
The enamel easiest to use for enameling on steel is a liquid, called Ground Coat. This liquid enamel can be found on Thompson’s website and here is your direct link.
Read what they have to say about mixing, applying and firing of liquid enamel for steel.
Coating Large Steel Panels by Spraying – Outdoor Sculpture and Signs
Larger works can be made from coating low carbon steel panels for sculpture, architectural panels and signs. Most often a ground coat (GC-16) is applied as the first coat. The ground coat adheres well to the steel and other enamels applied as subsequent coats adhere well to the ground coat. Low carbon steel is required as other types of steel create too much fire scale for good adherence of the enamel. Low carbon steel has a carbon content of .02% to .04%. Thompson carries low carbon steel in various sizes. Steel should be free of rust, grease or oil. Grease and oil can be burned off at a low temperature and heavy rust removed with emery paper. The entire surface of steel should be coated prior to the first fire. Although enamel powder can be sifted on, it is easier to use liquid form enamel for the first coat. Both sides can be coated by spraying or dipping and fired at the same time. Subsequent coats can be applied with normal techniques used on copper, silver, etc.
Mixing Instructions for Dry Powder:
For small items a simple way to mix is to place a half teaspoon of powder into a plastic spoon. Using an eye dropper add drops of water until the mixture is the consistency of ‘milk’. Apply to copper with a brush. Always make sure the powder and water have been stirred right before application as the glass falls out of suspension in the water very quickly.
For larger quantities mix 1/4 cup water to 5 oz. powder. To make a gallon of liquid, mix 14 lbs. of powder to 2 qts. of water. The water to powder ratio may be adjusted up or down if needed for your particular project. If the liquid dries out, you can grind it back smooth in a mortar and pestle to re-constitute.
Tips for Using Liquid Form Enamel
- Before application, always mix well as the glass quickly falls out of suspension in the water.
- The water content is extremely important to the application firing result you get. Too little water and your result may look like cottage cheese. Too much water and the coating may fire dark with little color.
- Colors can be intermixed when in liquid form to create new shades of color.
- Left over liquid form enamel that dries out can be re-constituted and used again. Take dry material and place in a mortar and pestle to break down any dried clumps. Add water and use again.
Make sure enamel product is completely dry before firing. For small pieces (less than 2” in diameter) fire at 1450 degrees F. for 1-1/2 to 2 minutes. For larger items (up to 6” in diameter) fire at 1450 degrees F. for 2 to 3 minutes. For much larger work firing times and temperature should be determined for your specific project. Firing times and temperatures are meant as a guide only. You may need to adjust up or down for your own situation/equipment.