Wednesday, November 4, 2009

Adventures in Prismacolor and Copper

Everything happened this month! My Subaru died an untimely but very spectacular death, I caught the (NOT swine) flu, I had unexpected administrative work to do at my university, and I was teaching overloads. Until this Monday I hadn't turned on my torch since the last time I updated!

I did try to fit some interesting things into the cracks and corners of time, and one of them was playing with Prismacolour markers on copper metal. The pieces aren't finished, but here's the fun I have been having. These pictures are from different projects that I have going all at once, not from one project start-to-finish.

I started with raw copper, either annealed, as in the first picture, or plain. Then I roughed up the surface with 220, 180, and 60-grit sandpaper to make the patina stick. The rougher the surface, the better. Afterwards, I pickled the annealed copper to remove firescale, and then thoroughly washed the copper pieces. Oil from your hands on the copper will prevent the patina from adhering to the metal. It needs to be fairly well bonded to the metal, unless you want copper showing through on your design.

Once your piece is clean, you can patina it. There are lots of formulae on the web that work faster or slower, so pick your poison and be *careful* handling it! My first time I used a commercial patinaing formula that I picked up at Binder's art supply. You can get a similar formula from JAX chemicals. I laid some of it on too thickly and didn't make my copper rough enough in others, so when I worked with the patinaed piece I had to be careful and use a very light touch--and incorporate the places where the bare copper showed through as part of my design. The next time I used the slower method of salt and ammonia, which produced a more durable finish. Some people on the net have suggested urine, which does have ammonia in it. While it may have been an acceptable laundry bleach substitute in Ancient Rome, and Lindsey Davis describes her character, Marcus Didius Falco, giving his landlady (the laundress Lenia) the ... umm ... results of his day's intake of fluids, I really don't want to use pee on anything I make, wear, or sell. Given the sheer amount of liquid my current foster dog, Gator, produces, it would be a cheap patina ... but no. Just no. Thank you.

I also made the mistake of sanding a larger piece of copper, putting a patina on it, and then sawing or snipping out my final shapes. Bad move, because even a strongly bonded patina can be delicate at this stage. My reasoning had been to make sanding and patinaing more efficient. However, next time I will sand a larger piece, then cut, drill, and file my final shapes, and then add patina.

Anyway, next comes the fun part! You guessed it--COLOR! I bought a few Prismacolor pencils in bright cheerful neon colours, and began laying them on the patina with a very light touch. Then I swabbed each piece with a bit of turpentine and let it dry. Next came -- you guessed it -- more colour, and so on until I was happy with the result or the copper would not take any more colour. I baked the pieces for about ten minutes in my oven (I want a dedicated toaster oven!) to melt the Prismacolour wax; the turps will not catch fire at 275 degrees. Then I sprayed the pieces with a lacquer. People have recommended Krylon for its short drying time, and I see why -- the stuff I had around the house took an age to dry! It wasn't an issue because I was fitting in these steps into the "cracks" of my day, but now that I have more time it is going to be a PITA to wait. Krylon, here I come!

If I liked the colour at that stage, I stopped there. If not, I sanded each piece with 0000 grit steel wool, very lightly, and did another set of Prismacolour and turps rounds, followed by another fast bake and another spray of lacquer, and so on until I was satisfied. Once I liked the colour, or knew that the piece was as good as it was going to get, I finished up with a spray of lacquer followed by a thin layer of that wonderful magical substance, Renaissance Wax. Then, you guessed it, I baked it for 10 minutes.

Finally, I used 0000 grit steel wool to sand each piece again, and buffed and polished it. With this lot I still have drilling and assembly to do, as you can see in the final picture (above). However, the next time I go through the process I will have pre-drilled, and all I will need to do is some final forming, if needed, and assembly. I want to add small lampwork beads to these pieces!

Metal and colored pencils and chemicals, oh my! How much more fun could there be? If you try this, by the way (speaking of fun) make sure you work outside or in a well-ventilated area. Turps and Renaissance Wax have noxious vapours, and filing / sanding metal isn't particularly healthy for the respiratory system.


Dave Robertson said...

A wealth of information - thanks for a good read this morning. I couldn't resist using your comment about pee as a pull quote in Twitter ;) (my bad!)

at Rings & Things

Four Tails Lampwork said...

I saw that and snickered. It'll definitely be a draw! :) Thanks for the RT.

Art of the Firebird said...

Do you have to patina or can you just use the Prismas on the sanded copper?

Cat said...

That is beautiful!

Four Tails Lampwork said...

I think so. The Prismacolour wax didn't stick to the sanded portions of my first attempts where the patina had flaked off. On the other hand, that might be because I hadn't roughed up the surface enough. I will try and see, but I think the patina is an essential part of the process. Which patina, though ... I wonder if a flame-applied patina, such as one gets from annealing a piece, will be enough. I have a lot of scraps I can use as test pieces. If you try, let me know!

I also wonder about watercolor pencils, and if they would work as well as the Prismacolours. It might be that they wouldn't need turps to dissolve the pigment, but at the same time their wax content might not be high enough to give good, saturated color. Again, I shall experiment and post results.

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Claire DeRosa said...

Great post! I'm going to try this soon. I just bought my pencils yesterday.