I have developed a valves and I need insert in the body model a metal coating feature.  I'm using Surface-Offset command with the dimension of coating wall to create this coating anf after I've using Thicken command to create the coating. But it's a complex surface and sometimes this commands don't work. I'm looking for an other way.... I can't use

The metal coating surfaces are in blue. I can't use cosmetic appearance or change surface color, I need a wall....