First, the genetics for plumage colours in silkies is no different than in any other breed of chicken. However, patterns do not look quite the same on feathers due to the nature of silkie feathering.
Partridge to partridge should always yield partridge; however, if a male is golden (has one silver gene and one gold gene), he will have both grey and partridge daughters, and sons may be golden as well.
Breeding blue to splash will give you about half and half blue and splash. Breeding black to splash willl give you all blues. Breeding blues to blacks will give you half and half blues and blacks. Breeding blues to blues will give you half blues and about a quarter each of blacks and splash.
You can breed blue to partridge and in a generation or two get nice blue partridge. First generation is likely to be incompletely penciled. Note that blue partridge is not a recognised variety.
What varieties do you have?