Learn Photo Etching on Metal with Karen Christians at MetalWerx,
Apr 3-4 2004, 9am-5pm, 2 days Tuition: $295 Materials: $55
Etching metal is very simple. Basically you have a mordant (acid)
and a resist to that acid. The resist can take many forms, plastic,
vinyl, Sharpie Marking Pen, duct tape, nail polish, etc. As long as
it resists water, you are fine. With current photocopy technology
and computer laser printer technology, you have more flexibility in
your designs. These are basically the same techniques as
printmakers use with zinc, but with brass, copper or bronze and
silver, you have options for additional fabrication choices
involving solder or cold connections.
Nitric/Hydrochloric Acid vs. Ferric Chloride/Nitrate
Ferric Chloride and Ferric Nitrate are slower etches and have extra
safety features. Nitric or Hydrochloric acid etching goes
While safer than nitric, these are still considered hazardous, so
close attention to the process is important. I have outlined safety
issues when necessary.
One great feature of the acid etch is the incredible textures you
can achieve by the action of the acid playing on the surface of the
metal. Somewhere between repouse,
It is important for anyone to use good quality Safety Glasses when
handling etching liquids. Also, a pair of household, well fitting
gloves is a good idea.
Ventilation is also a good idea. Tips on disposing the etching
solutions and the Material Safety Data Sheets (MSDS) are at the end
of the protocol.
A small Rubbermaid or other plastic tub, the size of a shoe box,
with a tight fitting lid
Ferric Chloride (for bronze, copper and brass); Ferric Nitrate
Duct tape and two sided sticky tape
Red Staedler ink pen (available at Office Depot, Staples,
Charette) or any drafting supply store
Cheap air pump from a pet store
Metal - 20-16 ga
3M PP 2200 Overhead Transparency Film
Curved burnisher or spoon
Mix of water and denatured alcohol, 2 parts alcohol, 1 part
water in a tight fitting jar
3M Scotchbrite pads, and a degreasing cleanser such as Comet or
Ajax or Penny Brite (the best)
Cheap pancake griddle. A new one will run about $35, but
finding an old one in a thrift store is perfect
Safety glasses, rubber gloves
Process: Image onto Metal
Select your metal. Start with a piece no larger than 3 x 3 to
begin. File any corners or rough edges until they are smooth.
Clean your metal with Scotchbrite and cleanser or Penny Brite until
water runs off your metal in a sheet. If you see the water beading,
then clean again. Scrubbing with Scotchbrite will serve to give the
metal a “tooth” and will clean it well. Dry with a towel and handle
by the edges.
Select your image and photocopy onto the PP 2200 overhead
transparency film. Images should be high contrast with visible
distinction between dark and light. The grey parts in between can
make it difficult for the acid to bite. Trim your picture so there
are no overlaps from the film over the metal. It’s best that you
leave a little extra metal around the edges.
Laser Printers vs. Inkjet Printers: Laser printers are basically
small photocopiers. They use the same kind of toner and scanning
technology. Inkjets use water soluble ink which will NOT work for
Heat your iron to “cotton” and your griddle to 250 degrees F.
Depending on the kind of iron you have, you may have to adjust the
heat. Overhead transparency film is designed for very high heat,
but some irons are extremely hot. I suggest some tests first.
Put one piece of your paper towel on the griddle. This is meant
to protect the griddle face, and also keeps the metal from skating
around. Many griddles have Teflon coatings these days. Don’t worry
about the paper burning. If you remember your Ray Bradbury book,
Fahrenheit 451, paper doesn’t burn until 451 degrees F.
Lay out all your supplies, the burnisher, tweezers, alcohol and
paper towel next to you for easy access.
First take a small wad of paper towel and saturate it with the
alcohol mixture. Clean one side of the metal and the TONER side of
your image. IMPORTANT!! And this is the trick to making the whole
process work for you. Make sure when you place the image side down
to the metal, that it is still wet. Squeegee out the excess
moisture and any air bubbles by rubbing your hand across the metal
and film. It doesn’t need to be dripping wet, but it does need to
Immediately place the metal with the film side up onto the paper
towel already warmed on the heated griddle. Immediately place
another paper towel over your piece and your iron on top of that.
Let the iron sit for about one minute. Carefully iron the piece for
about 20 more seconds and lift the iron. Remove the paper towel.
Place the burnisher in one hand and a tweezer in the other.
Carefully lift one corner of the film and see if the image has
transferred to the metal. If it hasn’t, replace the film and keep
heating. Sometimes, using the burnisher will help. Burnish the
image onto the metal. If it has transferred, remove the film, WHILE
HOT in one smooth stroke. Voila, you have your image. If it
smudges, then the iron is too hot, and takes it down a bit. The
nice thing about this process is that you can scrub the image off
and try again.
This will take a bit of practice, but in the end, you should get it
to work very well. Transfer the metal to a heat proof surface. A
metal block or anvil works nicely. Once the toner is on the metal,
it is very stable. I have had sample pieces that have been sitting
around for years that are as good as the day I ironed the images
- Troubleshooting. Sometimes the image does not transfer
completely. This is where your red pen can help out. You can fill
in some areas before the etching. Thicker gauge metal takes longer
to transfer than thinner. Large metal pieces can work, but you must
raise the griddle heat and spend more time ironing. As a rule, I
don’t try to use multiple pieces of film on one piece. If the metal
cools too much, the film will pull back the image. You can however,
do multiple images in stages. Silver heats up faster, so watch your
temperatures carefully. Remember, hot metal looks just like cold
Now that you have your image, you are ready to etch. Lay out your
supplies, acid, tub, duct tape, Styrofoam, two sided sticky tape,
safety glasses and rubber gloves, and the air pump.
Your metal should be clean. Use Penny Brite (citric cleanser)
or regular cleanser. Don’t scrub this time, rather mix a solution
in water or sprinkle the cleanser over the metal and rinse with
water. You can GENTLY move it around, but don’t use any pressure.
Dry in a clean paper towel and leave covered.
Tape the back with duct tape. Place two strips of double sided
sticky tape onto the duct tape. Cut a piece of Styrofoam to fit the
size of your metal. Compress the two together until it sticks.
Strap the air pump onto the side of your plastic tub. I actually
like to make this fixture, but using Velcro adhesive tabs. This is
very helpful and the gentle vibration won’t dislodge it. Why an air
pump? These cheap pumps are made to vibrate for long periods of
time. This vibration facilitates the etched residue to fall to the
bottom of the tub and keeps the exposed area of metal etching
Donning your safety glasses and gloves, pour the ferric chloride
into the tub, about 1/3 full. Try not to create bubbles, but a few
are ok. This should be performed in a well ventilated area.
Write down the time that you began the etch on the Styrofoam.
Strap the pump onto the side of the tub. Carefully lower the metal
into the solution. The Styrofoam act like little pontoons and make
sure that the metal is submerged correctly. Close the lid and plug
in the pump. Etching should take about 45 min to 1.5 hours,
depending on the depth of the etch you desire.
Check the etch every 30 minutes. Have a separate empty
container nearby. Pull the metal out and take it to a sink. Rinse
thoroughly. The small amount of ferric chloride isn’t enough to
harm the sink. Flush with water and rub your finger along the metal
to see how the bite is taken. If you need more, drop it back into
Etch done? Pull your piece out of the acid, drain well and bring
it to the sink. Fill your container with water and about a handful
of baking soda. This will neutralize the acid. Wait a minute after
it stops foaming. Rinse well. Refill the tub with a little more
water. Add about 1/8 c of ammonia. This acts as a stop bath for
the acid and completely arrests any leftover or trapped acid. Under
running water, or submersed, pull the tape off your metal. Clean
the metal again with the Penny Brite or cleanser and Scotchbrite.
This will scrub off the last of the toner. Now you are ready to use
your etched piece.