What's the environment? What are the safety rules?
Ultrasonic (US) welding in everyday life

In general :

• atmospheric pollution (grease, solvents, dust, etc.) is harmful to welding;

• certain chemical treatments (adhesion primers, solvents, cleaning agents, release agents, etc.), thermal treatments (flaming) or electrochemical treatments (corona, plasma, etc.) are harmful to welding.

Put yourself in the most favorable conditions.

Ultrasonic welding is less demanding than other technologies. It allows for certain types of pollution (foodstuffs, for example). If the constraints on the weld are not too draconian, you get a watertight weld.

Experiment to validate your welding procedure in...