Granulation, part III

Dear Orchidians, I have a friend who tries granulation using fine
silver granules on sterling backing. He is totally successful with
18kt gold granules on sterling, and 18kt on 18kt. After firing fine
granules on sterling, the granules are attached, but come off if
picked with a fingernail. Has anyone had better success? He does not
use the hot plate and torch method. Anyone just use torch firing
only? Richard in Denver