Caulk, Grout, and Joint Compounds Information
Caulk, grout and joint compounds are used to fill joints, level surfaces, and seal or repair cracks. There are two basic types of products: leveling compounds and sealing compounds. Leveling compounds are highly viscous materials that are applied with a trowel. Examples include chocks, fillers, and mastics.
- Chocks are used during the installation of heavy equipment or machine bases to provide a level or plumb surface.
- Fillers are suitable for closing gaps or repairing cavities in parts, castings, and structures.
- Mastics are designed for filling gaps before other materials are applied.
For example, they are often used to bond tiles to sub-flooring. Sealants are liquid compounds that contain fluids, prevent leaks, and block the ingress of unwanted materials. Typically, higher viscosity sealants are used when larger gaps need to be filled.
There are many chemical systems for caulk, grout and joint compounds. Examples include:
- Animal glues and gums
- Bituminous substances
- Ceramic and inorganic cements
- Epoxy resins
- Natural and synthetic rubbers
- Starches and starch pastes
- Silicone compounds
- Vinyl systems
- Wax-based compounds
Fluropolymers such as polytetrafluorethylene (PTFE) and polyvinylidene fluoride (PVDF) provide superior chemical resistance. Phenolic and formaldehyde resins offer strong bonds and good resistance to high temperatures. Other commonly used chemical systems include polyethylene (PE), polypropylene (PP), polyethylene terphthalate (PET), polybutylene terphthalate (PBT), and polyurethane (PUR).
Selecting caulk, grout and joint compounds requires an analysis of physical, mechanical, and thermal properties.
- Physical properties include viscosity and gap fill, the space between the material and the substrate.
- Mechanical properties include tensile strength and elongation, the percentage amount of deformation.
- Use temperature, thermal conductivity, and coefficient of thermal expansion (CTE) are important thermal properties.
Use temperature is the range of temperatures to which materials can be exposed without degradation of structural or other required end-use properties. Thermal conductivity is the linear heat transfer per unit area through a material for a given applied temperature gradient. The coefficient of linear expansion (CTE) is the amount of linear expansion or shrinkage that occurs in a material without a change in temperature.
Caulk, grout and joint compounds vary in terms of material compatibility and features. Some products adhere to ceramics or glass, concrete or masonry, metal, paper, plastic, rubber, or porous surfaces. Others are compatible with substrates made from composite materials, textiles, fabrics, or wood. In terms of features, many products that are designed for electrical and electronics applications provide protection against electrostatic discharge (ESD), electromagnetic interference (EMI), and radio frequency interference (RFI). Materials that are electrically conductive, resistive, insulating, or suitable for high voltage applications are also available. Flame retardant materials reduce the spread of flames or resist ignition when exposed to high temperatures. Thermal compounds and thermal interface materials absorb heat from electronic devices or electrical components.
Caulk, grout and joint compounds are used in many industries and applications. Some products are used in aerospace, automotive, marine, or military applications. Others are designed for use with electrical power products and high voltage applications. Materials that are suitable for medical, pharmaceutical and food processing applications meet requirements established by the Food and Drug Administration (FDA) and the U.S. Department of Agriculture (USDA). Original equipment manufacturers (OEMs) and repair, maintenance and overhaul (MRO) organizations also use caulk, grout and joint compounds.