This video shows probably the best and easiest way to achieve a long lasting repair to most lead work on a roof. A paint on roof sealer or roof coating alone tends not to last very long with lead, as lead movement caused by expansion and contraction is too great.
Typically this sort of lead repair will last years on a lead roof if you follow the instructions, but please be very careful when using any sort of heat.
Very useful for repairing a lead bay roof, a lead valley or gulley or a larger lead roof.