Acid Stain Using Copper

↞BACK

Sun face stained with copper-based acid stain.

If you make either of the following acid stain recipes, make sure you exercise proper precautions: Use goggles and rubber gloves and perform the operation outside or somewhere an acid spill would be relatively inconsequential if things go horribly awry. In short, always be careful.

Fast Method for Concrete Acid Stain Using Copper

1. Obtain some acid (either muriatic or sulfuric).
2. Obtain some black copper oxide...check with your local ceramic supply. Copper oxide is frequently used as a component in glaze formulas. Its not as cheap or easy to come by as plain wire, but its not that expensive either. I can obtain it locally for about $15/pound, but for about half that online. One pound will make a good bit of stain. If you don't have a convenient way to purchase copper oxide, you might want to consider making your own supply of CuO.
3. Slowly sprinkle about 1/8-cup of the copper oxide into about one cup of acid. Be sure to do this VERY SLOWLY! The reaction between the oxide and acid is exothermic and will very quickly heat up. You will find there is a fair bit of bubbling and fizzing as the oxide reacts with the acid.
4. You will wind up with a deep, dark green color solution that is immediately ready to use.

NOTE: Always be sure to keep the container covered when storing...acid fumes will badly corrode any exposed metal nearby.

Slow Method for Concrete Acid Stain Using Copper

Copper wire in muriatic acid.

1. Obtain some muratic acid (any hardware store should have it).
2. Obtain some copper wire (½-lb should be plenty to get the ball rolling).
3. Drop the copper into the acid.
4. The image to the right shows what I obtained when I poured enough acid to cover some old copper wire. The slight greenish color resulted from the copper oxide that covered the old wire.
5. Go do something else for the next several months. My experience is that it takes quite a bit of time for the rest of the wire to oxidize (I'm assuming this is what is taking place...I'm no chemist) and dissolve into the acid.
6. The acid shown to the right has been setting for a number of months. Note the deep green color. This stain can be used in its present form.

Copper and acid after several months.

NOTE: Always be sure to keep the container covered...acid fumes will badly corrode any exposed metal nearby.