What is rubber blooming?
You may often ask “What is that white stuff on the surface of rubber parts.
Most EPDM and NBR rubber materials undergo a process called “blooming” when they are stored. “Bloom” is a milky dusting of dry powder on the surface of the rubber. Typically, this is caused by unused vulcanizing agent(s) migrating to the surface of the rubber part.
Will it affect my rubber part’s function?
Bloom is entirely superficial. If the gray color is not acceptable, wash the rubber part in water or light mineral oil to remove it. Since blooming is entirely normal and does not affect the function of a rubber part, it is not considered a defect. Likewise, it is not considered a contaminant in the rubber material.