AST-SEAL Std (Standard Grade) from Anti-Seize Technology (Franklin Park, IL) is a general-purpose pipe sealant providing an instant permanent seal that cures in the absence of air to lock threads securely. This formula withstands temperatures from -65° to 300°F (-54° to 149°C) continuous and 375°F (191°C) intermittent. Meanwhile, the AST-SEAL HD (Heavy Duty) stainless steel grade is formulated for stainless steel alloy fittings to cure more quickly than standard grade anaerobic. This withstands temperatures from -65° to 400°F (-54° to 204°C) continuous and 500°F (260°C) intermittent.
The company recently produced a video in order to help inform users on how to apply both pipe sealants.