Hi, I'm a relative new to enameling, been dabbling for a few years, but have recently been trying to up my game. Problem being, I recently sawed a shape from 18 gauge copper, did everything well as far as I could tell, the enamel melted fine and everything looked good until I pickled it.
What would cause the pickle to eat the enamel off the copper? Turned it a terrible color as well. I must have the blend too strong, but it didn't do it to other pieces. And when it wasn't as potent, it wouldn't take off the fire scale very well.
Any Advice? Thoughts? Thanks for any feedback. Am learning as I go.
Susan
Hi Susan,
Some colours of enamel are easily etched by acid, including pickle. In my experience, opalescent enamel and some types of white are particularly sensitive and prone to discolouration and pitting. I personally avoid pickling most enamel pieces and prefer to remove fire scale mechanically (with polishing and abrasives). It is likely that the problem you encountered was specific to the enamel you used, and that the colour you chose was acid sensitive. I doubt there was anything wrong with the pickle. You could etch off the enamel (I've had success with glass etching paste), and recover your copper shape to try again. I'd definitely make a note about the acid sensitivity you encountered, so you can plan whether or not you pickle that colour in the future.
Christine Woollacott
Why would you pickle a project once you started to fire it. Depending on who you applied the base, putting your project in acid would disintegrate the base and partially remove the enamel. Copper is not the material to place in acid once you have started to fire. Fire scale is caused because the metal wasn't cleaned properly. Read my article on cleaning and prepping metal on notebook #1 center of page steel preparation. A lot of problems occur because of not properly cleaning the metal and applying a base. Don't touch the project with bear hands once you have cleaned the project. I wear brown cotton gloves. This keeps the oils from your fingers and hands from transferring to the project. Your body oils will keep the enamel from adhering to the project evening before firing. Have fun and don't get discouraged. I have problems all the time, and I have learned to work through them. This site should make your problems easer to work through. Don't be afraid to experiment. Learn your kiln temperatures and time. and most of all have fun.
Sincerely
Charles Winkel
When I first started enameling, I had a question about white colors and called Thompson Enamel. My problem was different from yours, but they were so helpful and explained a lot to me including what you have read in this thread: that some colors are acid sensitive. The biggest help was the recommendation of the Thomson Handbook. If you are using their colors, it will save you a lot of aggrivation and it's very inexpensive.