It has been said on Pinterest that one can make a caribbean blue stain out of pennies soaked in vinegar for a week.
To the frustration of many pinners, this has experiment has failed over and over again.
But before I knew this, I wanted to take a stab at that oh-so-gorgeous penny stain! I love it when I can experiment with science AND art. It's, like, what my brain was made for or something. Luckily, my brain is also wired to do research before starting such a project (lesson learned from many childhood volcanos gone wrong. *Shudder*). I figured there HAD to be some sort of ratio of vinegar to pennies, estimated time lapse, etc. etc. etc.
This is when I found out if you throw a handful of pennies in vinegar for a week you get a niiiice big chunk of!!!!.... nothing. So what's the dealy, yo? Luckily I found the answers!
There are two important facts to note if you want to do a penny stain.
1. Not all pennies are created equal:
"In 1962, the cent's tin content, which was quite small, was removed. That made the metal composition of the cent 95 percent copper and 5 percent zinc. The alloy remained 95 percent copper and 5 percent zinc until 1982, when the composition was changed to 97.5 percent zinc and 2.5 percent copper (copper-plated zinc). Cents of both compositions appeared in that year." - US Mint.gov
I also read another blogger who experimented with pennies and vinegar and found that she had most success with pennies from the 1960's. So maybe it is the tin from pennies before 1962 that contributed to the deep blue? Not sure on the details yet, but 1960's pennies DO work the best (as you will see later in the blog post).
2. You can't use vinegar alone!
There must be an introduction of oxygen in order to get any chemical reaction going. This can quickly be done by adding a secret ingredient. Are you ready for it?
Just add even a couple of tablespoons and you are going to get yourself a stain in a matter of hours. This is why no one was having success by just adding pennies to vinegar.
So I decided to try a little experiment. Since I didn't want to waste time copying other experiments, I just did two jars of pennies mixed with vinegar and hydrogen peroxide.
Here were my results:
I was actually quite shocked at how quickly the chemical reaction happened on my jar full of pennies from the 70's through the 2000's. It literally happened in a matter of minutes. However, the 60's took a couple of hours to start looking blue. It did, however, start to turn blue on the first day.
Yet oddly while the 60's penny stain stayed blue, the other elixir did not. The 60's got more and more blue, and the 70's through 2000's color practically diminished by day 3. It was completely gone by day 5. I was actually quite bummed because I was excited to see what sort of colors each stain produced. They were so different! I wonder if I had only used pennies before 1982 (when they changed to mostly zinc) it would have stayed that cool, mossy green color (hey, YOU should give that one a shot!)
But as it was, my 1960 penny stain won out, and that was what I used on my wooden sign.
I had enough stain from about 6 oz of vinegar and 2 tablespoons of hydrogen peroxide to do 6 coats on 3 wooden letters. It turned into a BEAUTIFUL greenish blue hue. I wasn't ever planning staining all of my letters. I also wanted to try modge podging some beautiful tissue paper I've been saving for months onto one of the letters, and the last letter was saved to pay homage to the source of the stain itself. I literally wanted pennies EVERYWHERE! The tissue paper letter was just an added bonus.
(Side note: I also read that the stain isn't "stable" so it is a smart idea to seal the stain. I just used modge podge over the stained letters as a sealant)
This is how the final product turned out:
AWESOME, RIGHT!?!?!? Wow, I was so surprised at how pretty it turned out. I think I'm going to hang it on my wall over my makeup area. But seriously, imagine how pretty this stain would be on some old wood furniture? Game boards, bird houses, the possibilities are ENDLESS.
So now you know how to do a REAL penny stain, the right way. Get to it! And send me pictures of the masterpieces you make. I would love to see it all :)