Overview
Etching is a form of printmaking that has existed since medieval times, using acid and acid-resistant chemicals applied to flat sheets of metal to produce an textured surface capable of holding ink. The plates themselves are quite beautiful, capable of holding rich line work and elegant transitional shading. Many metals can be etched in this technique, I wish to experiment with an ipod case. This will require removing the ipod case, dipping it several chemicals, and then snapping it back together. The finished product will place a custom image on the ipods' metallic shell. Theoretically, this process could work for any flat metallic surface, like cell phone cases or computer cases. If tested properly, the process could be be executed in less than 6 hours.
Materials
- Metal surface
- Acid
- Many kinds will do. Nitric, Hydrochloric (both extremely diluted), I have experience with ferric chloride. It's relatively safe and capable of etching copper and zinc in less than an hour. For iPod etching, hydrochloric is recommended.
- A container to hold the acid is implied. Must be big enough to contain the entire metal sheet at once.
- Acid resist
- A wide variety of supplies can resist acid. Many are expensive art supplies, such as Ashphaltum mixed with mineral spirits or ZCryl, but Futura Floor Wax will do the job. For my money, ashphaltum holds really fine lines which plays to my strength as an artist, but cost may be a factor. These are used in the intial line etching.
- Spray paint - color irrelevant, it's used here as an acid resist.
- Etching tool
- A sharp metallic point will do. Actual artist etching tools are cheap. $7 last time I checked, I already have two. Hair pins or sewing needles will work in a pinch. Any sharp metal point that won't break will do. Sharp as you can get for preference.
- Paintbrushes
- A variety of sizes and cheap. They will be useless for anything else after this.
- Metal Polish compound
- This has a proper name I don't remember. It's late and I'm tired. More later.
- Dremel with buffer attachment
- Potential workarounds ???
- Imagery
- Optional
- Burnisher - for taking scratches out of the metal surface before we begin.
Now the Hell Will Start
- Remove the Case From Your Ipod -
- Requires elaboration from IMod's expertise
- Preparing the surface
- Might want to clamp the case down so it doesn't fly away as soon as you put pressure on it.
- Use a dremel with a small buffing wheel, possibly a brillo pad over the surface to remove the logo or any offending scratches
- I'm told this can be done with a sand blaster, but it seems like that would require a ridiculous amount of polishing and burnishing to get the surface back.
- Remove all oils from the surface using a special burnishing compound called, um, I've forgotten.
- Further research required.
- Take a little dab of the stuff and apply to the plate, less than a finger tip. Polish with a paper towel, and old sock, or a power sander. Power sander works very well.
- Coat the entire object with acid resist
- Floor wax or Emulsion can be poured over the plate at an angle. Plate should be rotated to allow the liquid to move over the plate as it dries. You want a fine even coat with minimum of streaks - streaks can can fluctuations in the exposure. This will probably dry in about 20 minutes. Will not be sticky or tacky when it dries, but may show a special sheen.
- Ashphaltum can be brushed on, but it is fumey. Mix four parts ashphaltum with one part mineral spirits and stir well with a wide brush. Brush the ashphaltum mix over the entire plate as evenly as possible. Again, lift different sides of the plate so the liquid can move over the surface getting a fine, even coat. Streaks aren't as big a problem with ashphaltum, but bubbles should be brushed over. Ashphaltum can take a long time to dry, I reccommend leaving somewhere hot and well ventilated. A hot plate, or on a porch on a sunny day might work. It could still take up to an hour. Will have a similar texture to the floor wax when dry.
- If you're etching something like hardware casing it will have multiple sides, each side must be coated thoroughly. The object will be dipped in acid, and any area not covered in the acid resist will be be burned.
- Make your image
- An image can be transferred to the plate with carbon paper (or improvised carbon paper)
- Add instructable on carbon paper
- Use the sharp point of your etching tool to re-draw your image. The point is used to chip of the emulsion wherever you wish your line work to appear. At this stage, tone and shade cannot be created, except for hatchmarks.
- If using floorwax, fine line work is trickier because the wax has a tendency to clot and chip, exposing larger areas than intended. This should be taken into account, as it can work for your image if you want something to looked rugged or roughed up.
- Immerse the object completely in acid. Consult an etching chart to see how long to immerse the specific metal you're using. Ferric Chloride typically takes about 45 minutes for line work.
- If you are etching a plate to print onto paper then text must be flipped horizontally to read on the paper. For the ipod case, the plate itself is the final product so text does not need to be flipped.
- iPod casings are made of steel, which does not etch cleanly in ferric chloride - the only kind I have access to. Apparently hydrochloric acid is far more effective with steel, but I'm a little intimidated by its toxicity and storage issues.
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