Source: NASF
Tanks are used in nearly every step of the surface finishing process, from plating and rinsing to storage. Every step places unique demands on your tanks. Selecting the right tanks contributes to the long-term success of your entire process. Seacole is here to help you decide which tanks are right for your surface finishing line.
Chemical, Temperature, and Electrical Insulation Considerations for Surface Finishing Tanks
Every step in your surface finishing process requires different chemistries, temperature tolerances, and even insulation against electrical currents. Some tanks are ideal for acidic processes, while others should only be used for alkaline chemistries. Additionally, if the chemicals in your process are highly corrosive, choosing a tank with high chemical resistance is imperative.
Often, surface finishing processes involve chemical reactions that produce heat. Other processes, such as electroplating, require tanks to withstand electrical currents. Consider both the temperature of your process and the need for electrical insulation when selecting tanks for your surface finishing process.
Plastic Surface Finishing Tanks
Most plastic tanks are excellent insulators for temperature and electrical currents, making them ideal for high-temperature processes or electroplating. The most common materials for plastic surface finishing tanks are polypropylene, PVC, polyethylene, and Kynar®:
- Polypropylene: The most common tank material for metal finishing, due to its low cost, chemical resistance, and appearance. Use for rinse water or with acidic or alkaline materials. Do not use for nitric or chrome processes.
- PVC: Most common tank for chrome processes. Has a shorter lifespan.
- Polyethylene: Ideal for molded, round storage tanks.
- Kynar®: A greater investment but offers excellent chemical resistance. Ideal for high temperatures. Do not use for high alkaline materials.
Steel Surface Finishing Tanks
There are several different types of steel tanks for surface finishing. All steel tanks must be lined for electrical insulation if used in plating. The most common types of steel tanks are mild steel and stainless:
- Mild steel: Low-cost, but suitable only for alkaline chemistries. Most mild steel tanks are coated with epoxy on the outside for durability.
- 304 stainless steel: An affordable option for stainless steel and ideal for most chemistries except fluorides and chromic acid. Must be lined for electrical insulation if used as a plating tank.
- 316 stainless steel: Often used for applications involving high-temperature pure water. Like 304 stainless steel, 316 stainless shouldn’t be used with fluorides or chromic acid. Must be lined for electrical insulation if used as a plating tank.
Lined Surface Finishing Tanks
Lined tanks are tanks lined with PVC, Kynar®, or Teflon®. In some lined tanks, the liner is bonded to the tank walls. Other times, a bag or rigid liner is retrofitted into an existing tank to insulate it against electric current or fix a leak. PVC is the most common liner material for plating tanks, though it is not ideal for temperatures over 150 degrees Fahrenheit. Kynar® and Teflon® are ideal for high temperatures and processes involving chrome and fluorides.
Don’t Overlook Ventilation
Another key, yet often overlooked, consideration in choosing the right tank for your surface finishing process is ventilation. To keep employees safe and your surface finishing line productive and efficient, you must properly ventilate your process tanks. The design of your process’s ventilation hood, ductwork, and scrubbers must ensure that hazardous fumes are safely scrubbed and ventilated out of your facility.
Choosing the right tanks for your surface finishing process can be complicated, so rely on the expertise of the Seacole surface finishing team to help you identify the best tanks for every step in your process. Contact the Seacole team today.
