Caulking materials, generic

Description

Any material used to fill or seal joints and openings. Many names have been used historically and commercially for these materials including:

• caulking (noun); caulk (verb); calking (sp); cauking (sp.); sealant; putty; spackle

For this database, the term 'Caulking' will be used. This table tries to include most types of materials that have been used. For a specific comparison of commercial products, please see: Comparison of commercial caulking materials.

Caulk/putty	Earliest use	Composition	Examples	Applications	Characteristics and Risks
Fibers/Wood	ancient times			boats
Wax	ancient times			vessels	becomes soft with heat
Tar	ancient times			boats
Oil-based caulk (sometimes lead-based putty)	19th-20th c.	10-15% linseed oil with calcium carbonate, red or white lead and sometimes other inorganic fillers ( talc, alum, asbestos)		Seal window to frame, fill defects in wood and metal; surround pipe joint	Lead compounds accelerate drying; some components are toxic
Cement putty		concrete		mortar
Gesso putty		gelatin with chalk
Rubber (natural, vulcanized)	19th c to WWII			gaskets, shock mounts,	waterproof, can crack due to ozone
Polysulfide (Thiokol)	1950s	Any synthetic rubber vulcanized with sulfur (Neoprene, styrene-butadiene, polyisoprene)	Neoprene, Thiokol	o-rings, pipe linings, building joints, and as sealants to fill joints in pavements, and glass/metal connections.	may release sulfur; may contain PCBs; poor tensile strength; abrade easily; replaced in 1980s by silicone and urethane sealants
Butyl rubber	1950s	Isobutylene-isoprene, talc calcium carbonate, mineral spirits, ahesion promoters		primarily used outdoors for metal and masonry joints that may expand and contract (gutters)	sticky and messy, but more resistant to sunlight than natural rubbers; combustible; paintable
Acrylic (solvent-based)	1958	solvent cured acrylic resin with calcium carbonate, silica, solvent and plasticizer.
Silicone	1960s	silicone resin cured with moisture or peroxides; may contain fumed silica, calcium carbonate, ground quartz, carbon black, talc, plasticizers, acetone,, methylene chloride.	Silastic, Clear Museum gel	used around plumbing fixtures; to caulk joints in bathroom tiles; seal gap on exterior walls/roofs around pipes and wirings	water-repellent; long-life; wide temperature range; mold/mildew resistant; not paintable; poor adhesion; may release acetic acid or methanol on cure; may have residual curing compounds and silicone oils; may stain porous materials; some silicone caulks contain latex making them paintable but less durable
Polyurethane elastomers	Polyurethane cured with moisture; calcium carbonate, titanium dioxide, aromatic naphthas and petroleum distillates;		Vulkem	primarily used for sealing cracks and expansion joints in driveways and other outdoor concrete surfaces. It's also suitable for filling and repairing cracks in masonry-stucco walls.	very durable; abrasion resistant; flexible at low temperatures; combustible producing toxic fumes; may release acetic acid on curing, aging, or deterioration; susceptible to hydrolysis that may decrease adhesion
Vinyl latex	late 1960s	Vinyl (polyvinyl acetate) or Acrylic emulsion in water with calcium carbonate, plasticizers	Reprosil	fill small gaps and blemishes in wood trim prior to painting	inexpensive; may be painted and used outdoors; may evolve trace acetic acid as it cures
Acrylic latex		Butyl methacrylate, calcium carbonate, water	Flugger	fill small gaps and blemishes in wood trim prior to painting	inexpensive, fast-drying, and paintable; minimal shrinkage; used indoors