Etching sheet metal requires the use of some rather strong acids. It is important that you exercise extreme caution when using these acids and that you dispose of them properly--and NOT by dumping them down a convenient drain. Not only will these acids hurt the drain itself, but they are highly toxic to the environment and dumping these acids into the water system is illegal. The best acid to use in sheet metal etching is muriatic acid, also known as hydrochloric acid. Hydrochloric acid may be difficult to obtain. If you are not able to purchase hydrochloric acid, purchase sulfuric acid (swimming pool acid) and add 1-cup of salt to each gallon of sulfuric acid. Add the salt slowly and stir gently with a wooden spoon. Adding salt to sulfuric acid turns it into hydrochloric acid. Always wear heavy protective clothing, eye protection and gloves when working with these acids.
Things You'll Need
- Sheet metal
- Hydrochloric acid
- [Sulfuric acid and salt]
- Enamel paint
- Plastic tray
- Glass containers for used acid
- Heavy protective clothing
- Eye protection
- Breathing mask
- 1 pound of baking soda
- Paint brush
- Paint remover
Trace the design to be etched onto your sheet metal in pencil.
Paint all areas that are NOT to be etched with a good enamel paint. Paint edges and the back of the sheet metal as well. Any bare metal will be etched.
Allow the enamel paint to dry and then place the sheet metal into a plastic tray that is just slightly larger than the item. Carefully pour hydrochloric acid onto the sheet metal until the areas being etched are covered by approximately 1/4-inch of acid.
Allow the item to soak in the hydrochloric acid for at least 1 hour. Visually inspect the item after 1 hour and see how deeply it is etched. If it is not etched as deeply as you would like, continue soaking in acid, rechecking each hour. Do not leave in the acid bath for more than a maximum of 4 hours.
Pour used acid into a glass container that will be taken to your local Hazardous Waste Materials site. Cover your sheet metal item with clean water and then pour in 1 pound of baking soda to neutralize any residual acid. Allow to soak in baking soda for 20 minutes. Remove from the soda bath and rinse with clear water.
Using a paint brush apply paint remover to the enamel paint. Allow to sit for at least 10 minutes or per manufacturer's instructions. Wearing gloves, wipe clean with coarse cloth. Apply a second coat of paint remover if necessary. Wipe and wash with soapy water. Your etched image should now be plainly visible.
Tips & Warnings
- Always wear protective clothing when dealing with acid. Spills and splashes will eat through most fabrics.
- Always wear eye protection, a breathing mask and gloves.
- Always dispose of used acid properly. Carry acid in a glass container to you local Hazardous Waste Disposal facility
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