Blu-Tack is a versatile, reusable putty-like pressure-sensitive adhesive. The original version of the product was blue, but many colours are now available. It is based on a formulation consisting of synthetic rubber, polymers, oil, and inorganic fillers
Blu-Tack can leave an oily stain on paper materials if attached for a long period of time.
Laboratory Researcher Alan Holloway, working for Sealant Manufacturer Ralli Bondite of Waterlooville Hampshire, had in 1970 inadvertently produced a product that was useless as a sealant, but pliable and semi-elastic. This novelty product was demonstrated by Ralli Bondite management to visiting executives from another sealant and adhesive manufacturer, as a means of wall mounting notices. There was no need for secrecy about the formula, as it was of no use for a gun-grade mastic, the main product of Ralli Bondite. In the beginning the potential of this material was not fully recognized, until later when Bostik did commence research into the development of what they were eventually to launch as Blu-Tack. In its conceptual stage the product was white, but was coloured blue in response to concerns received from marketing research regarding the possibility of children mistaking it for edible candy.
Similar products from other manufacturers include "Buddies" (coloured pink), "Pritt-Tack", "Tac 'N Stick" and "Sticky Tack". "White Tack", made by the German company UHU, is similar but, as the name suggests, is white, so coloured so that it doesn't show through easily on posters as Blu-Tack does.
Blu-Tack is also used for sculpture. Artist Elizabeth Thompson created a giant 200 kilogram sculpture of a spider using Blu-Tack over a wire frame. It took 4000 packs and was exhibited at London Zoo in 2007. Other serious artists have created works from the material, and there is a large international body of keen users of Blu-Tack who create minor art works and stop-motion animation. The British Blu-Tack web site takes a keen interest in these activities and has a section devoted to them.
In the UK in March 2008, Blu-Tack (again, see UK web site) changed colour for the first time since 1971 - to pink - to help raise money for Breast Cancer Campaign. 200,000 numbered packs were made available, 10p from each pack going to the charity. The formulation was slightly altered to retain complete consistency with its blue counterpart. The traditional blue colour returned in April.