Basic Acid Etching
Ld. Cai Dubhghlas
This article is designed to
teach a person how to use chemicals I will refer to as "acids"
to etch a design into a piece of material. The hands on tutorial
portion of this paper will take you through the steps necessary to etch
a design into a brass disc using readily available supplies. Next
after the tutorial, I will discuss what materials can be etched using
chemicals and what chemicals to use to etch them. The last section will
cover some suggested locations for materials used in these processes.
Section 1
The materials provided by
this class are:
(1) brass disc 1-1/2” diameter and about 1/16” thick
Piece of plain white paper
Paper towels for drying
Brass-O
Mineral Spirits
The Tools used in this class
are:
Scratch Awl (or any hardened steel tip device such as drafting dividers, compass, etc.)
Ball Point Pen
Sharpie Marker
Pyrex glass dish to etch in
Plastic dish for stop bath
Tongs
Scotch-Brite Pad
To Begin:
Decision
To begin the process you need
to choose a design that you would like to place on your disc.
Line pictures or simple black and white designs work best since you
will only be able to show 2 surfaces (your starting surface and your
sunken, etched surface). When you have chosen your design, make
a Xerox copy of it on a copy machine and cut it out to the size you
want it on your disc. Make sure that you leave space for yourself
to drill at least one or two holes in the disc so that you can hang
in on a chain or cord.
Preparing the Metal
Metal Preparation is the most
important step as it will decide just how well your piece will look,
and after you’ve etched rarely can you come back to this step.
The disc provided to you has been precut to a round shape and has been
deburred to prevent the edge from cutting you. However, you will
need to use the scotch-brite pad to shine up the brass and remove any
oxidization that has occurred. Using a product called Brass-O
will also help remove oxidization on the piece, but the scotch-brite
pad will smooth out any cuts in the surface of the metal as well.
The polish is important because the smoother the surface the better
the resist sticks to the piece. To finish this process we will
begin to "paint" the disc with the sharpie marker. Take
your time and make long smooth strokes with the marker to ensure a solid
even coverage of resist. Let one side dry and then coat the second
side as well. Please make sure to coat the edge as well, remember
that acid will eat any piece of exposed metal and leave its mark.
Placing your Design
For this class we will be tracing
the outline of the disc on a piece of copying paper and then marking
a circle where you would want holes drilled. Then you should draw
your design onto a piece of copying paper with a pencil. Make
sure to not get too close to the border of your outline. The next
step is to cut out your artwork along the outline tracing you made of
the disc. We will then tape this down onto the resistant-coated
disc blank. Once the design is place onto the disc you will want
to trace the design you have made with a ballpoint pen, this allows
you to follow which parts of the drawing you have already traced over.
This method, taught to me by HL Barbarrossa, has the interesting effect
of transferring the design to the resist by creating small depressions
in the resist which are visible enough for a person to follow.
Once you have traced all points of the design, you should carefully
remove your paper and tape. Make sure not to jerk the paper away
quickly as you may take more resist with the tape and paper than anticipated.
Once the paper is removed you should see a faint outline of your drawing
in the resist. You can use the faint outline to guide your stylus
as you remove resist from your piece.
This step will involve the
use of a steel point of any kind, which I will refer to as a stylus.
Following the lines left in your resist, begin to carefully scratch
away the resist using your stylus. This is where skill is needed
to "stay within the lines" so to speak. Every scratch
you make with your stylus will transfer itself into the piece.
You can cover some goofs by incorporating them into the design, painting
over that section again or simply making a line wider. As you
scratch more you will get the hang of this. When doing large areas
that need to be removed, be patient and work from one side to the other
removing the resist, going back to clean up as needed.
Etching
Once your design is scratched
into the resist, you will want to brush away the resist crumbs lightly
with your fingers. Now place your disc in the glass dish with
the scratched side up. We do this so that the acid will always
be able to get to the metal and continue working. Now carefully
pour your acid into your dish. Use only enough acid to submerge
the work piece completely under the acid. Be sure to be
very cautious when using any type of acid, it is very corrosive and
caustic. Acids also produce dangerous vapors so be sure to do
this in a well-ventilated area and using protection such as gloves and
safety glasses. Now your piece is submerged in acid.
At this point you should cap and store your acid solution. It
will take anywhere from 70-90 min for your design to be etched into
your disc. The acid we are using is a diluted form of Ferric Chloride
(which technically is a Salt).
Cleanup
After you piece has been submerged
in the acid for the desired length of time, remove it using a pair of
tongs and place it into the plastic stop bath dish filled with water.
Then remove the disc from the stop bath and wipe it down with a paper
towel. To remove the resist, all you need is to dab a paper towel
with some mineral spirits or paint thinner and rub it on the piece.
Then you will want to polish up you piece with some Brass-O to make
it shine.
Long Term Care
Maintenance of your etched
piece depends on the material you etch. Glass requires virtually
no maintenance, steel requires a wax or oiled coating to keep it from
rusting, stainless steel needs no maintenance, brass and copper may
require the occasional polishing using Brass-O to remove the oxidation.
Section 2
Materials that can be Etched
and what I would recommend Etching them with
Most any metal can be etched
and many non-metallic surfaces. However I will only give you a
list of what I have done and know will work, please feel free to experiment
and research anything else.
Glass
Any glass surface can be etched
using the commercially produced paste found in most department stores
and hobby stores. The resist in glass etching is most commonly
contact paper or tape. You might try other resists but tape and
contact paper are the cheapest and easiest to use, I would consider
etching glass the easiest of all media. The paste sold on the
market is designed for hobbyists and is very safe. Can be cleaned
in your normal sink.
Brass/Copper
Brass and Copper are grouped
together because Brass is primarily made of copper so their inherent
etching properties are similar. A person can use a diluted form
of Nitric Acid to etch these materials, however I would caution them
because of its ability to produce noxious fumes (caustic). One
of the best solutions to use for etching copper and brass is ferric
chloride. Ferric Chloride is a salt and it is VERY dangerous.
However, there is a commercially produced diluted solution that can
be bought cheap at most Radio Shacks, known as PCB (Printed Circuit
Board) Etchant. This is the very same stuff used in the class
to etch the brass discs. Resists for this etchant can be sharpie
marker, enamel paint, asphaltum varnish, tape and contact paper.
All of these resists work because PCB etchant works slowly so there
is minimal undercutting and destroying of design.
Aluminum
Like any other metal, aluminum
can be etched. There are few solutions or acids that will work
with aluminum, however I have taken a preference to Ferric Chloride.
The diluted form discussed under Brass/Copper is the same that I use
for aluminum. However instead of getting a 90min etch, aluminum
will react much quicker, say as in 10-15 min. When etching aluminum
you will notice that the piece will form bubbles on the surface where
the metal is exposed. These bubbles will need to be brushed off
otherwise they will interfere with the acid eating its way into your
metal properly. For this process the only resist I will use is
asphaltum varnish. Because of the quick reaction time, this process
is dangerous and tricky, but when done with the proper variable can
create some very interesting etches, sometimes looking like sand castings.
Steel (non-stainless)
Steel is the media in which
I have worked the most. The first acid I used was a solution of
Aqua Regia that HL Barbarrossa made himself. Under his guidance
I learned what it was like to etch metal. Experimentation and
the guidance of Master Thorkill led me to find other just as viable
alternatives. Currently I use a 10% nitric solution with water
to etch steel with (thank you Mistress Katrei for helping me read the
labels). This will give a clean sharp and deep etch in about 30
min at room temp. Asphaltum again is my resist of choice because
of its durability, having been designed explicitly for use in acid etching.
Steel has been etched over the centuries by most commonly vinegar, as
well as citric acid, such as found in oranges. I used phosphoric
acid (a can of Coca Cola) once to etch a steel medallion. After
48 hours it gave a faint etch, I can only assume that a higher concentration
or greater volume was needed.
Stainless Steel
Stainless is best etched using
commercially produced electo-etching kits. They come in many sizes
and forms for small and large equipment. A good all purpose marking
kit can be bought for a reasonable price from Etch-O-Matic on the internet.
To etch stainless with just the use of chemical, no electrical assistance,
is one of the most dangerous methods because of the nature of the acids
and the by-products produced.
Section 3
Materials
The media that you etch (brass,
steel, glass, etc.) can be found in many locations across the world.
With the advent of the internet, raw materials can be had from about
any location. Some things to keep in mind when looking for media:
brass kick plates for doors, glass mirrors, aluminum light switch covers.
Below are some places where I frequently visit to find the tools of
the trade.
Brass, Copper, Steel, Aluminum, Stainless Steel
The Yard (Surplus Store)Wichita, KS 316-265-4672
Ace Hardware (Hobby Store, look for closest near you)
Walmart (Dept. Store, look for closest near you)
Hobby Lobby (Hobby Store, look for closest near you)
Joann Fabrics and Crafts (Hobby Store, look for closest near you)
Michaels (Hobby Store, look
for closest near you)
Asphaltum Varnish (resist)
LJ Pracht (Hobby Store) Wichita,
KS 316-265-3146
Sharpie Markers, Scotch Brite Pads, Paper Towels, Mineral Spirits, Plastic and Glass Dishes, Ball Point Pen, Paper, Brass-O
Ace Hardware (Hobby Store, look for closest near you)
Walmart (Dept. Store, look for closest near you)
Hobby Lobby (Hobby Store, look for closest near you)
Joann Fabrics and Crafts (Hobby Store, look for closest near you)
Michaels (Hobby Store, look
for closest near you)
Acids
Radio Shack (Hobby Store, look for closest near you) - Ferric Chloride
Walmart (Dept. Store, look for closest near you) - Glass Etching Paste
Hobby Lobby (Hobby Store, look for closest near you) - Glass Etching Paste
Joann Fabrics and Crafts (Hobby Store, look for closest near you) - Glass Etching Paste
Michaels (Hobby Store, look for closest near you) - Glass Etching Paste
Science Education Center (Hobby Store) Wichita, KS 316-682-1921
- Hydroclouric Acid, Nitric Acid Reagents (must sign a release form)
Tongs
I made mine from a strip of
folded over stainless steel since it doesn’t react with most acids
that I use.
Stylus
Any hardened steel point: drafing
compass or dividers, engraving stylus, sharpened steel rod, knife blades.
Of all the places that I have
gone too looking for supplies, Ace Hardware would win out as the best
"one stop shop." I have included local supply houses
with their local phone numbers in case you want something they may have
and you can't find it elsewhere you can call and see if they can ship
it to you.
And if you are still lost and
needing help, or if you want to discuss this process, give me a call
or drop me an e-mail. I work mundanely for a living so please
be patient for replies, below is my info.
Ld. Cai Dubhghlas CLM, CT, CIF
Barony of Vatavia, Calontir
Aka Wayne Brown
Wichita, KS
316-269-9129
Reference: