A male 45 years old wants his missing teeth to be replaced. Intraoral examination reveals Kennedy class 4 edentulous maxillary arch. Impression is made with alginate. All of the following are true about the material except:
Since alginate is a viscoelastic material, its tear strength is increased when the impression is removed along a vertical path with a snap.
It is always best to avoid torquing or twisting the impression in an effort to remove it quickly. Specifically, the handle should be used minimally during breaking of the air seal (“suction”) or removal  of the tray from the teeth.
The compressive strength of alginate doubles during the first 4 min after gelation, but it does not increase appreciably thereafter. Most alginate materials improve in elasticity over time; this minimizes distortion of the material during impression removal, thus permitting superior reproduction of undercut areas. It is possible to leave an alginate impression in the mouth too long. 
Data clearly indicate that the alginate impression should not be removed from the mouth for at least 3 min after gelation has occurred.

Key concept: The alginate impression should not be removed from the mouth for at least 3 min after gelation has occurred.
The compressive strength doubles during the first 4  min after gelation
It is a viscoelastic material
Its tear strength is increased when the impression is removed along a vertical path with a snap
Impression should be removed from the mouth within 3 min