Some of the bee supply firms sell a simple hive scale. An arm extends up by the side of the hive, as the hive increases in weight, the arm moves across an arc (kind of like a sundial) and the weight can be read. Relatively inexpensive, but probably as accurate as bathroom scales, which we found to be poor out-of-doors. The mechanical ones rust up, the electronic ones fail rapidly. Jerry Bromenshenk [log in to unmask]