Caulk

Spry, now displayed on shore Traditional caulking (also spelled calking) on wooden vessels uses fibers of cotton and oakum (hemp) soaked in pine tar. These fibers are driven into the wedge-shaped seam between planks, with a caulking mallet and a broad chisel-like tool called a caulking iron. The caulking is then covered over with a putty, in the case of hull seams, or else in deck seams with melted pine pitch, in a process referred to as paying, or "calefaction". Those who carried out this work were known as caulkers. Henry Mayhew described the work done by caulkers in London on the hulls of wooden sailing ships in September 1850, In riveted steel or iron ship construction, caulking was a process of rendering seams watertight by driving a thick, blunt chisel-like tool into the plating adjacent to the seam. This displaced the metal into a close fit with the adjoining piece. Caulking of iron and steel was also used by boilermakers in the era of riveted boilers to make the joints watertight and steamtight. ==Modern use in construction==

Application For bulk use, caulk is generally distributed in disposable cartridges, which are rigid cylindrical cardboard or plastic tubes with an applicator tip at one end, and a movable plunger at the far end. These are used in caulking guns, which typically have a trigger connected to a rod which pushes the plunger, and has a ratchet to prevent backlash. The push rod may also be actuated by a motor or by compressed air. Similar mechanisms are used for grease guns. For smaller applications, caulk may be distributed in squeeze tubes. Closed-cell rod will also lose firmness and out-gas if damaged during installation or overcompressed or at sharp bends. The gasses cannot pass through this backer rod and can deform, weaken, and even cause holes (leaks) in the caulk or sealant as it escapes. Out-gassing is the reason that open-cell backer rod was developed. ==Types==

Acrylic latex The most common type of caulk is acrylic latex, for general-purpose use. Not only is acrylic latex inexpensive, but it is also the easiest type to apply smoothly and later paint if needed. Acrylic tile sealant Acrylic tile sealant usually comes in small tubes and is commonly used for wet applications. It's commonly used for sealing ventilation systems. Silicone Silicone caulk or sealant is water-, mold-, and mildew-resistant. ==See also==