How to determine if drum foam is expired?

How to determine if drum foam is expired?
To determine if drum foam is expired, consider the following:

Check the production date and expiration date: First, check the production date and expiration date on the drum or label. Generally, the shelf life of drum foam is between 6 and 24 months. If the storage conditions are met, if the marked expiration date has passed, the foam is likely expired.

Observe the appearance: After opening the drum lid, inspect the foam. If there is separation, sedimentation, abnormal color, or visible particles, the foam may have deteriorated. For two-component drum foam, also check that both components are in good condition; any abnormalities may affect its use.

Test physical properties: Take a small amount of foam and perform a simple physical property test. If the foam has a noticeable change in viscosity, becoming too thin or too thick, it may be a sign of expiration. Additionally, normal foam glue has a certain expansion rate and an appropriate curing time after foaming. You can test a small amount of foam glue to observe its expansion and curing time. If foaming is minimal, nonexistent, or the curing time is too long or too short, it may indicate that the foam glue has expired.

Evaluate the adhesive bond: Apply the foam glue to a small piece of wood, wait for it to cure, and then peel it off to assess its bond strength. If the bond strength is significantly reduced and easily peeled off, the foam glue may be expired and ineffective.