/project/TOC/finishes/nonfe/H2O2.html

"Processes, methods, and apparatus presented herein have not been tested or verified by ArtMetal in any way. Anyone using any of this information is doing so at their own risk."

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Hydrogen peroxide (H₂O₂ ) pickle eliminates the need for abrasives, and has the added attraction of being relatively inoffensive. The following procedures and formulas provide for the removal of red scale from copper, brass, bronze, nickel silver, reticulation silver and some gold alloys. It will remove the copper coating from silver that has been accidentally pickled in an iron contaminated acid. Curiously, it will also remove the natural oxide layer found on aluminum. There is a great deal of latitude in the formulas and a variety of surface finishes and textures can be obtained.

It is suggested that you run some tests before applying these formulas to your work. Find the procedure that best fits your needs. When working with any acid the possibility of damaging your work always exists. These formulas can dissolve a brass piece and leave the silver solder seams standing.

Adding more acid to the solution will not improve its action. The acid is just a catalyst or starter.
Iron and silver will tend to shorten the life of the bath. This does not mean you cannot put these metals in the bath.
Use only sulfuric acid, Sparex or vinegar as the catalyst in these solutions.
Use 3% hydrogen peroxide available in drug stores, or mix a 2-3% solution from distilled water and concentrated H₂O₂ (usually 30%), available through a chemical supply house. More concentrated pickles (5%) can be mixed when deep, fast etching is desired. (Warning! Concentrated acid is very dangerous. Do not attempt without proper training and equipment.)

Always add acid to water!
Use these solutions warm(110Â°F), or about the temperature of a hot bath. The hotter the pickle; the faster and coarser the etch.

The following formulas can be made up as needed, or they can be premixed and kept for an extended time in the original brown bottle. It can be reused until saturated (blue) and it stops working. Hydrogen peroxide decomposes rapidly when exposed to light. The active life of these pickles is limited to about four exposed hours. Put your solution back in the brown bottle for storage.

The acid component of these solutions can be either measured or slowly added until bubbles begin to appear on a sample of the metal. This signals that the solution is active.

SOLUTION #1(mild):

SOLUTION #2(strong):

PROCEDURE:

Prepickle the piece in standard Sparex or sulfuric acid solution (5-10%) and rinse. All the black oxides should be removed.
Place the Hydrogen Peroxide pickle container in a second bowl of hot water to keep it warm. If possible suspend the piece in the warm pickle. After a moment bubbles should appear on the piece. Agitate or brush with a feather to clear the bubbles. Remove the piece from the bath every couple of minutes to check the progress. It may take 5-10 minutes. Rinse well.
Use a stiff tooth brush or brass brush to remove residue and rinse
Pickle again in standard Sparex or sulfuric acid solution (5-10%) to remove any remaining smut.
Repeat steps #2, #3 and #4 if necessary.

SOLUTION #3:

PROCEDURE:

Follow the steps listed for solutions #1 and #2. When the metal emerges from the pickle, it will be coated with a thick brownish green smut. This will flash off when dipped in undiluted white vinegar.

Long term exposure to these pickles can cause the copper to be dissolved out of an alloy's surface. Brass, for instance, can be pickled until it turns bright yellow. Even the mildest of the vinegar solutions can deeply etch if left unattended. A deep etch will often reveal the underlying crystal structure of the metal. Care should be taken and the process watched closely.

As is the case with all corrosive solutions, these formulas should be handled with care and in good ventilation

Hydrogen Peroxide pickle does not remove firescale from sterling silver. Sorry!

Author: Bill Seeley

HTML Editor: Roger Schmitt

ArtMetal Curator: Enrique Vega

Last Updated:Sun, Jan 21, 1996