How to electropolish aluminum

TL;DR

Learn how to electro polish aluminum using basic equipment like phosphoric acid, a battery charger, and an air pump.

Transcript

hey everyone I've been developing a technique to electro polish aluminum I haven't found much on the internet regarding this technique so I thought I'd share what I've learned this is an unknown aluminum alloy and as you can see I have electro polished it here and this is the stock finish this is another bar this is known to be 6061 aluminum and th... Read More

Key Insights

• 💅 Electro polishing aluminum can be achieved using basic equipment, such as phosphoric acid, a battery charger, and an air pump.
• 🫢 The technique results in a smooth finish on the aluminum, but there may be some pitting caused by gas bubble formation.
• 🎮 Temperature control and surfactant additives can help improve the electro polishing process.
• 🛀 The process is more effective when the aluminum piece is fully submerged in the acid bath.
• ❓ Different acid blends and electrolyte concentrations may yield varying results in the electro polishing process.
• 🕰️ The voltage and current density applied to the aluminum piece affect the effectiveness of the electro polishing.
• 💅 Phosphoric acid at 75% concentration and 75°C temperature, with a current density of 100 mA/cm², is a recommended recipe for electro polishing aluminum.

Questions & Answers

Q: What equipment is needed for electro polishing aluminum?

The basic equipment includes phosphoric acid, a battery charger, an air pump, stainless steel plates, and a vessel to hold the acid bath. Other optional equipment includes a heat source for maintaining temperature control and better process control.

Q: What safety precautions should be taken when handling phosphoric acid?

It is recommended to use gloves, eye protection, and splash protection when handling phosphoric acid. While it is not as dangerous as other concentrated acids, precautions should still be taken to avoid any harm.

Q: Why does the aluminum need to be fully submerged in the acid bath for electro polishing?

Partially submerged aluminum parts can get damaged by the spraying acid, so it is necessary to fully submerge the entire piece for an even and effective electro polishing process.

Q: Why does pitting occur during electro polishing?

Pitting can occur at higher current densities due to the production of gas bubbles on the surface. These bubbles prevent electrochemical polishing as they create a barrier between the aluminum and the polishing solution.

Summary & Key Takeaways

• The video demonstrates an electro polishing technique for aluminum using phosphoric acid and basic equipment.

• The process involves creating a circuit with stainless steel plates, immersing the aluminum piece in the acid bath, and applying an electric current.

• The resulting finish is smooth and polished, but there may be some pitting due to the chemical reaction.