The generic name "potting compounds" applies to all types of products which can be applied in bulk fluid form and subsequently become
relatively rigid; including sealants.
Potting compounds and sealants have various uses in spacecraft: electrical and mechanical insulation, damping, sealing and thermal coupling. They appear in practically all subsystems.
Three main chemical groups of polymers predominate: epoxies, silicones and polyurethanes. These exist as hardened potting compounds, sealants, foams, and syntatic foams (containing micro-balloons). Pigments, fillers and dyes are often added to these organic
All these products vary from soft and elastic to hard and rigid. Specific gravity is from 0,1 for some foams to more than 2 for bulk-filled resins. Syntactic foams are between 0,5 and0,8. Before the hardening (curing) process, potting compoundsare liquids, pastes or even powders. Some cure by atmospheric exposure (one-part systems), others by the addition of a catalyst (two-part systems).