Etching Recipes – Safety and Guidelines
Etching is a fascinating process, but it requires careful handling of materials and strict adherence to safety guidelines. Different acids react uniquely with different metals, meaning that the choice of acid and its concentration will significantly impact the final result. For example, nitric acid works differently on copper than on zinc, and ferric chloride behaves differently with aluminium compared to brass. To avoid contamination and maintain control over your etching process, it’s essential to dedicate one bath for each type of metal.
I’m Jenny Mason-Gunning, and in my workshops at our Ironbridge studio, I guide participants through these principles, ensuring that safety is always the top priority. Protective clothing, including gloves, masks, and aprons, is essential, and working in a well-ventilated area with an extractor unit is highly recommended. Proper handling and disposal of acids and mordants are just as important to protect both yourself and the environment.
Whether you’re working with traditional materials or exploring non-toxic alternatives, it’s crucial to follow all safety precautions and use these materials at your own risk. In my workshops, I create a safe and supportive environment where you can learn the ins and outs of etching, from line and tone to experimental techniques.
If you’re interested in expanding your skills or discovering more about safe etching practices, I’d love to welcome you to one of my workshops at Ironbridge. Together, we can explore this incredible art form while keeping safety at the forefront.
Etchant – Nitric Acid
Strength: Nitric Acid comes at 70% strength and is highly harmful. Handle with extreme care.
Health & Safety
- Nitric Acid emits harmful gases—wear a mask and full safety gear.
- Always mix acid into water (never water into acid).
- Ensure an extractor unit is used.
- Decant acid safely at the end of the day.
Mixing Guide
| Metal | Mix Ratio | How to Mix |
|---|---|---|
| Copper (Strong) | 2 parts water: 1 part acid | Add water first, then acid. |
| Copper (Weak) | 3 parts water: 1 part acid | Add water first, then acid. |
| Steel (Strong) | 5 parts water: 1 part acid | Add water first, then acid. |
| Steel (Weak) | 8 parts water: 1 part acid | Add water first, then acid. |
| Zinc (Strong) | 10 parts water: 1 part acid | Add water first, then acid. |
| Zinc (Weak) | 18 parts water: 1 part acid | Add water first, then acid. |
Spit Biting: For neat acid, mix a small amount with water to activate etching and paint onto your plate.
Disposal: Do not tip acid down the sink. Take to your local waste facility for proper disposal.
Non-Toxic Mordant – Saline Solution (Copper Sulphate + Salt) - This is not 100% Non Toxic but still pretty amazing to use
This is a safer alternative to acids. While it is non-toxic once mixed, always wear gloves and a mask when handling and NEVER dispose of down the Sink – this will kill aquatic life. Very few fumes come of this and it wont burn you but the salt can sting. Once this has been mixed up you can leave out on the side in the workshop
Mixing Guide
| Metal | Mix Components | Instructions |
|---|---|---|
| Weaker Mix for Zinc and Aluminium | 10L water, 500g copper sulphate, 125g table salt | Dissolve salt in water, then add copper sulphate. Ready to use once fully mixed. |
| Stronger Mix for Steel and Zinc | 1L hot water, 200g salt, 200g copper sulphate + 1L cold water | Dissolve salt and copper sulphate in hot water, then add cold water. Ready to use. |
Rejuvenation: Add 100g copper sulphate and 100g salt dissolved in 0.5L water to refresh the solution.
Disposal: Leave solution in an open tray to evaporate into a powder, which can be disposed of safely in the bin.
Etchant – Ferric Chloride
This traditional etching method can be used for copper, brass, and zinc but requires frequent agitation and plates to be etched face down or vertical
Mixing Guide
| Metal | Mix Ratio | Notes |
|---|---|---|
| Copper | 1L Ferric Chloride (38° Baume’) : 4L water – measure with Hydrometer and alter accordingly | Protective gear is essential. Never add in the water the ferric always add in the ferric to the water and wear protective gear and clothing. |
| Zinc | 33° Baume’ (fast) | Ensure an extractor unit is used; handle it with care. |
Disposal: Do not pour down the sink. Take to your local waste facility for advice on proper disposal.
Etchant – Copper Sulphate
A versatile option for etching copper, zinc, and aluminium.
Mixing Guide
| Metal | Mix Ratio | Instructions |
|---|---|---|
| Strong | 100g copper sulphate : 1L water | Mix copper sulphate into water and stir well. |
| Weak | 50g copper sulphate : 1L water | Mix copper sulphate into water and stir well. |
Dispose Responsibly: Never pour used etchants or mordants down the sink. Instead, take them to your local waste disposal facility. Alternatively, allow the solution to evaporate in an open container until it crystallises; the solid residue can then be safely discarded in the bin.
Important Reminders
- Test Your Plates: Always create test plates to refine your process for line and tone. This ensures you achieve the desired effects before working on your final piece.
- Health and Safety First: Never skip safety precautions. Wear gloves, masks, and protective clothing, and work in a well-ventilated space with an extractor unit if needed. Your health and safety are essential when working with chemicals and etchants.
- Dispose Responsibly: Used etchants and mordants must be disposed of properly. Do not pour them down the sink—take them to your local waste disposal facility to protect the environment and adhere to safety regulations.
By following these reminders, you can enjoy the creative process while ensuring a safe and responsible printmaking practice. Stay safe and happy etching! 🎨✨