Both 8021 in 8011 aluminum alloys are suitable for aluminum foil cold forming, but there are some differences in their properties.

8011 aluminum foil alloy:
8011 aluminum alloy is a common choice for food packaging and pharmaceutical packaging applications.
It is known for its excellent cold forming and deep drawing properties.

8021 aluminum foil alloy:
8021 aluminum alloy is a high-performance alloy with better mechanical properties compared to 8011.
It is commonly used in pharmaceutical packaging and blister packs to provide enhanced barrier properties to protect sensitive medications.
8021 aluminum foil is known for its ability to maintain a high level of integrity in harsh conditions and provides greater protection against moisture, light and gases.

The choice between 8021 in 8011 depends on the specific requirements of your application. If you need a foil with excellent barrier properties and resistance to external factors, 8021 may be a better choice. If your main concerns are cost-effectiveness and ease of molding, the 8011 may be a better fit.