Some sealants release plasticizers or unreacted silicone fluids that wick into marble, limestone, granite and concrete, leaving a dark band along both sides of the joint that also attracts dirt. The stain is usually permanent. Stain testing with the actual stone, as in ASTM C1248, and specifying non-staining grades prevent it. Bleed also describes color running from a sealant into a coating applied over it.
There's a dark halo an inch wide on every limestone joint, that's bleed from the wrong silicone.
Also heard as
- staining
- bleeding
- fluid migration
Related terms
Silicone
A sealant with a silicon-oxygen backbone, prized for UV resistance and high movement capability.
Compatibility test
A lab check that a sealant and the materials it touches do not react, discolor or lose adhesion together.
Mock-up
A full-size sample of a wall, window or joint assembly built and tested before the real work starts.
Sealant
A material that fills a joint or gap to stop water and air, while accommodating movement.
Same word, different worlds
Separation of oil from a grease, either as a storage problem or as the intended release of oil to a bearing.
Boilers & BurnersTo let trapped air out of a hot water radiator, baseboard or high point by opening its small vent until water appears.
Vacuum EngineeringTo admit a small, controlled flow of gas into a vacuum system through a needle or leak valve.