A sealed assembly is made using sealant including a deformable spacer to control thickness without adversely impacting elasticity and sealing force. Deformable spacers (e.g., elastomer, polyolefin, etc.) are mixed with an elastomeric precursor material and dispensed onto an assembly component, such as a fuel cell bipolar plate, and the remaining component(s) are assembled by pressing against the deformable spacer to ensure a defined seal thickness. The precursor is cured to form a seal that is further compressed to provide an effective sealing force. The deformable spacers control the thickness of a sealed area and allow use of form-in-place sealing processes.