7/27/2019 Advanced Etching of Copper

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Advanced Etching of Copper, Brass and bronze

This method of etching uses a prepared ferric chloride solution which also contains hydrochloric acid. This"etchant" is not a pure acid, but etches copper and copper alloys (like brass and bronze). It will not work onsilver. It is available from electronics supply shops, such as adio !hack or from chemical suppliers. It isgenerally used to clean or etch copper circuit boards. It can also be found at some printmakers supply stores.

#dvantages over #cid etching$

•

not a pure acid% does not re&uire dilution% is not as dangerous or tricky to use• resists are readily available and easy to use$

• permanent markers that are made for writing on plastic can be used as a resist, which allows for

drawing and writing directly on the metal. 'hotocopies, li&uid floor wa and packing tape can also beused as resist

• fast working, clean bite

MATERIALS:

• "tchant" (ferric chloride)

• selection of pens or tapes for resist

• glass or plastic container with lid, big enough to hold piece of metal

• baking soda (bicarbonate of soda)• emery paper (fine) or superfine steel wool, or brass brush

• methyl hydrate or isopropyl alcohol

• rubber gloves, plastic tweezers

RESISTS:

PERMAET MAR!ERS$!taedtler *umocolour +-, +- / 0% our eperience shows that the transparent red works best, but all

transparent colours eg. green and blue, seem to work as well. The opa&ue black tends to lift off during theetching process (it may be that it has more pigment to make it opa&ue).

!harpie permanent pens. 1e found they do not adhere as well as the !taedtler ed, but other 2ewellers have

mentioned using them. periment with different brands to find the one you prefer.

TAPE:cello tape, clear and brown packing tape (3rand 4 Toy call it "Tan Tape", a brown cello tape)

P"#T#C#PIES:This specialized techni&ue is described on another page. 5irst you should read the methods described below.

MET"#$:

-. 6lean metal to be etched. !hould be grease free with no scratches. 5inal finish should have a slighttooth (ink seems to adhere better than to a highly polished surface), but scratches which are too deepallow the tchant to get underneath the ink and lift the ink off the surface. #n ideal finish is achieved by

rubbing with wet 788 1et 4 0ry paper (emery or corundum) or scrubbing with wire brush, scotch briteor superfine steel wool. !cour in a circular motion and rinse under clean water. !urface must be veryclean and grease/free.

9. 0raw on metal with the pen / !taedtler pens come in various thickness of tips. 1e use the ":" (wide)and "!" (fine). 1here you put ink will resist the etching action of the chemical. #reas that are left freeof ink will etch. The inked areas will remain in relief. If you are etching a piece to be used as a patternfor roller printing another piece of metal, remember the 0!I3; 1I** < =!0. This is importantif you are using letters or numbers. emember to reverse the design. >old design up to a mirror tocheck everything is the right way around.

. 6lear 6ellotape or <rown packing tape will resist tchant and lasts longer than the ink. Tape is good forsharp/edge geometric shapes. !tick tape to a piece of glass and cut out shapes with an acto knife.3ently lift tape off glass with tweezers and press down onto the metal.

?. 'rotect the back and edges of metal from being etched by applying Tan Tape to the back and edges of

metal. This saves a lot of pen ink.@. 'ut etchant in glass or plastic container. ead the label for safety precautions. !ubmerge piece intotchant with the design facing down (to allow particles of copper to fall away and not interfere with theetching process). It is best to suspend the piece in the solution, so it is clear of the bottom of the

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container. ither hang the piece from a wire strung across the container (you can make a tab of tape toattach to the wire) or tape on pieces of plastic to hold the metal above the bottom. #gitate the solutionfre&uently by gently knocking the edge of the container.

7. 0epending on how much you have used the solution, the piece will be ready in 8 minutes (for newsolution) to up to 9 hours (old solution, used many times). 5or &uick action, do not dilute the solution.

. tchant has an advantage over acids, in that it does not undercut, but cuts straight down from theresist. The surface that has been etched away has an attractive teture showing grain growth of themetal (shown here in a piece of etched bronze / a pen was used for resist). Aou can "pierce" a design,by leaving the piece in the solution until it has etched right through to the backing tape.

B. I:'CT#;T$ 1hen the piece is etched to the desired depth, remove the piece and wash immediately

with water and scrub with an old toothbrush or brass brush and baking soda (or ammonia solution).The baking soda will neutralize the tchant and stop the etching action. If the tchant is not completelyneutralized, it will continue its etching action.

D. emove the ink with alcohol$-8. emove !taedtler inks with methyl hydrate (wear rubber or late gloves and use in well ventilated

area)--. emove !harpie inks with ispropyl (rubbing alcohol)

tched pieces in bronze, brass and copper can then be$

• patinated green or black and the surface sanded clean

• used to imprint another piece of metal using the rolling mill

• set like a stone in silver

• enamelled (if made of copper)

• inlayed and soldered into another metal

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