Wednesday, February 19, 2014

Playing with Patina

I've been having fun playing in my studio with different patinas on copper.  These are the humble Canadian pennies that I start from.  They have to be 1996 or earlier (American pennies have to be 1982 and before).  The newer pennies don't contain enough copper and they just kind of explode into a molten mess when you heat them.
I found an awesome tutorial for making leaves in the Spring 2012 issue of Belle Armoire Jewelry.  Thanks, Lisa Weber!  Lisa's leaves were exquisitely done in silver but I have a copper budget and a few pennies that I have hoarded since the Canadian penny became obsolete.

I started by rolling the pennies flat in my rolling mill (a recent acquisition).  Then after a few more steps: annealing, quenching, folding, cutting, texturing, annealing, quenching, pickling, unfolding, filing, bending, sanding and cleaning, they were ready for the patina. And after making more than a dozen leaves, so was I! 
MAPP gas torch 
The flame from the MAPP gas torch is comparatively hot (hotter than propane or butane).  This lovely patina is just from waving the flame gently over the copper but not too long or you'll get fire scale. 
Peanut oil and MAPP gas torch
These ones are also done with the MAPP gas torch but first I coated the leaves with a thin coat of peanut oil using a paper towel.  They turn a lovely golden colour with a dark brown mottled effect.
Propane torch
Using the propane torch the same way as the MAPP gas torch, I got a little more variety in the colours.  I find that some of the lovely colours I get with either torch kind of disappear when I apply wax after the patina.
Ammonia and salt
This was my favourite patina.  I spritzed the copper with water and then sprinkled salt over the pieces.  Then I filled a small dish (about 1/4 cup) with household ammonia and set the earrings, right side up, beside the dish.  I then covered everything with a glass cake topper to keep the ammonia fumes contained next to the copper.  I left it overnight and the next morning I gently rinsed and wiped away the salt before waxing the earrings.
Novocan Black
For this pair I used Novocan black patina which is a chemical used on stained glass copper foil after soldering for a nice black finish.  I brushed some of the patina on the copper and, as it started to blacken, I sprinkled salt over it and got these lovely speckles.
Verdigris
This is the green colour one normally associates with aged copper.  This was the fiddliest patina so I plan to try a few other methods to see what will work the best.   For these earrings, I soaked a paper towel in vinegar and sprinkled it with salt.  I wrapped the earrings in the paper towels and set them under a small halogen lamp (about 6 inches away but be careful not to leave it unattended as the lamp can get really hot).  I left them for about 2 hours to get this green.  I gently wiped away the salt before applying the wax but I didn't rinse them as some earlier attempts had washed away the green patina. 
Oven-roasted
I did these ones in a toaster oven for 20 minutes at 350 degrees.  They turned kind of a golden brown with a hint of burgundy.  I think I'll try them in a slightly hotter oven next time...maybe a conventional oven.

I tried some other experiments that didn't give any noticeable results, such as lye, urea, and sodium bisulphate.  But I'll keep playing and share the results here....eventually.

I finished my pieces off with a coat or two of Renaissance Wax.  You can also use S100 which is a wax available at your local Harley dealer for polishing the metal on motorbikes.  It's a mix of carnauba wax and beeswax. 

2 comments:

  1. Your copper work is very beautiful. Thank you for posting your photos, comments, suggestions, and - mentioning rolling mills. I searched for rolling mills online but didn't know what they were called. Would you please share with me the brand you purchased? Thanks much. Shirley in Turner, Oregon

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    1. Thanks, Shirley. Here is the link to the one that I purchased. It's a Durston and made in England with solid steel rollers. There were much cheaper ones available here and there online but reviews weren't good on any of them. http://www.lacytools.ca/Rolling-Mill-Sheet-Wire-80-mm-p/28115.htm. I'm really happy with mine!

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