For more tips, see the comments on our post about removing rust from your boules
Why blacken your boules? Perhaps you want to make it easier to tell your boules from other players’ boules. Perhaps you simply like the color.
Gun blacking wears off quickly. Black magic marker (permanent marker) leaves your boules slightly sticky. Kim Badcock, of the Mission Beach Petanque Club in Australia, has a better suggestion.
A soak or wipe-over with a very weak acid solution (vinegar, lemon juice, yellow mustard) will change the outer molecular layers of your boule to magnetite (“black rust”). Quickly wipe with an oiled cloth afterwards to help seal in the coloring.
This should work with all carbon-steel boules. It shouldn’t work with stainless steel boules or with chrome-plated boules (which means that it shouldn’t work with leisure boules).
Following Kim’s suggestion, I bought a jug of distilled white vinegar. I left two La Franc SB boules to soak in the vinegar overnight. (La Franc SB boules are relatively soft carbon-steel boules, acier au carbone.) In the morning they were really black. When I washed them off, a lot of black came off on my hands. The boules were left with a deep uniform matte gunmetal grey color. There was a small shiny spot where they had been sitting on the bottom of the container.
In this picture, the brownish boule in the front is a rusty boule that has been brought back from the dead. The two vinegar-blackened boules are at the back. The boule at the left has been played with more than the boule at the right, so it is more scratched-up. The image doesn’t really capture the color of the boules. The boules, while not absolutely black, are a much darker grey than they appear in the photo. In play, they do appear to be black.
Click to see larger image.
This picture was taken immediately after I treated the boules. The color was relatively long-lasting, but after about 5 months and about 50 hours of play, the boules began to look a bit shiny. So I blackened them again. Soaking them for 6 hours in distilled white vinegar restored them to the condition that you see in the pictures.
If you happen to find some rusty old boules, don’t throw them away. They can be restored to playable condition. Here is a La Franc SB carbon-steel boule that I accidentally left outside in the summer heat and rain. It is covered in a thick coat of orange rust.
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This was not a disaster. A few minutes with a wire brush, and a few more minutes dragging the boule around on the ground to simulate a few days of play, and the boule was restored to playable condition. The boule on the left (see photo, below) is the restored boule. The boule on the right (from the same set) was kept out of the weather. The restored boule is darker in color and has a rougher surface (which I like), but otherwise the two boules are basically the same.
Click to view larger image.
In this case, all I needed was a wire brush. If you have a boule for which that isn’t enough, then soak the boule in distilled white vinegar for a day or two. The acetic acid in the vinegar will soften the rust so that it can easily be scrubbed away. (If I’d used a vinegar soak first, I probably could have saved myself a lot of elbow grease with the wire brush.) Afterwards, remove the vinegar by thoroughly rinsing the boule with water, or with a weak solution of baking soda to neutralize the acetic acid.
A quicker solution is to use hydrochloric acid, which can easily be found (as muriatic acid) in stores that sell swimming-pool maintenance supplies. But I would recommend that only for extreme cases.
There are also products called rust converters that don’t remove rust, but chemically convert it to a hard, black, stable material called iron tannate. Rust converters are often used to restore and preserve iron-based historical artifacts such as old swords. For more information, Google (or search amazon.com or Youtube) for “rust converter“.
Note that it is also possible to use a short vinegar soak to blacken boules.
The moral of the story is that if you come across some rusty old boules, don’t write them off. They can be restored to playable condition. Depending on your taste, they may even be better than they were before they got rusty.
During the off season I like to play solitaire. To make it easy to distinguish the two sets of boules, I cover one set pretty completely with black magic marker. When regular play resumes, I can easily remove remove the black marks with a product called “Goof Off”. You might be able to find it at your local hardware or hobby store. Otherwise, it is available via Amazon.com or from www.goof-off.com.