A putty knife is a specialized tool used when glazing single glazed windows, to work

putty Putty is a material with high plasticity, similar in texture to clay or dough, typically used in domestic construction and repair as a sealant or filler. Although some types of putty (typically those using linseed oil) slowly polymerise and be ...

around the edges of each pane of

glass Glass is a non- crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling (quenchin ...

. An experienced glazer will apply the putty by hand, and then smooth it with the knife. Modern

insulated glazing Insulating glass (IG) consists of two or more glass window panes separated by a space to reduce heat transfer across a part of the building envelope. A window with insulating glass is commonly known as double glazing or a double-paned window, ...

may use other ways of securing the glass to the window frame. A spackle knife (called a scraper in

British English British English (BrE, en-GB, or BE) is, according to Oxford Dictionaries, "English as used in Great Britain, as distinct from that used elsewhere". More narrowly, it can refer specifically to the English language in England, or, more broadl ...

, also known as a

spatula A spatula is a broad, flat, flexible blade used to mix, spread and lift material including foods, drugs, plaster and paints. In medical applications, "spatula" may also be used synonymously with tongue depressor. The word ''spatula'' derives f ...

American English American English, sometimes called United States English or U.S. English, is the set of varieties of the English language native to the United States. English is the most widely spoken language in the United States and in most circumstances ...

) is also commonly called a "putty knife", and is used for scraping surfaces or spreading material such as

plaster Plaster is a building material used for the protective or decorative coating of walls and ceilings and for moulding and casting decorative elements. In English, "plaster" usually means a material used for the interiors of buildings, while "re ...

in various

construction Construction is a general term meaning the art and science to form objects, systems, or organizations,"Construction" def. 1.a. 1.b. and 1.c. ''Oxford English Dictionary'' Second Edition on CD-ROM (v. 4.0) Oxford University Press 2009 and ...

trades. Widths from 1" to 5" or 6" are commonly available. Wider-bladed knives up to about 12" are used for sheet rocking. Larger blades are made, but generally lack the stability of the smaller blades and do not make a perfectly flat surface. Stiff-blade knives, typically 1 mm or .040" thick, are suitable for scraping. Flexible-blade knives, typically 0.5 mm or .020" thick, are suitable for spreading. Due to the conductive nature of metallic blades, they should be kept at a safe distance from electrical components. Disposable knives, with handle and blade molded as a single piece of plastic, are suitable for occasional jobs such as spreading roof patching tar or mixing two-part adhesives, avoiding laborious cleanup which may involve hazardous solvents.

See also