TotalBoat Halcyon that is in good condition should be completely cured for at least 48 hours under normal conditions, and sanded/prepared per the recommendation of the new varnish. If the Halcyon is bubbling, flaking, or generally in poor condition, it will not provide a good foundation for the new varnish, and should be removed.
IMPORTANT! Two-part varnishes should not have compatibility issues when applied over TotalBoat Halcyon, but it is not recommended. Always test for compatibility and adhesion in a small, inconspicuous spot if a two-part varnish is strongly desired.