Axel Karlson had been producing a product known as "Karlsons Klister", which was originally intended for use in the repair of women's stockings, but had quickly found use in other applications as well. In February 1929, Karlson convinced Nils F. Testor, then the manager of an F.W. Woolworth store in the Swedish district of Rockford, Illinois, to serve as office manager of his new enterprise. It was a relatively risky move for Testor, who began his career as a stockroom boy in Woolworth's Chicago store on State Street. Karlson's Klister ultimately proved unsuccessful and Karlson returned home to Sweden. Testor borrowed enough money to purchase the firm's assets and founded The Testor Chemical Company. By the time Testor arrived, cobblers had become the product's primary market. Coming to the conclusion that the only way to save his new acquisition was to sell the product to additional markets, Testor renamed the adhesive "Crystal Clear Household Cement" and began marketing it to households as a general-purpose repair product, while continuing to sell a large quantity to shoemakers. Testor's actions proved to be successful, and by 1936 the company was able to expand its product line. Staying true to its status as a chemical corporation, hobbyist model cement and butyrate dope were introduced to the public. Four years later, Testor Corporation became a founding member of The Hobby Industry of America, an association of hobby parts suppliers and manufacturers.
Industrial production, necessitated by World War II, caused severe shortages of raw materials for manufacturers not directly involved in the war effort. In Testor's case, this manifested itself in difficulties acquiring the chemicals necessary to continue producing its line of adhesives and paints. As a result, the company was forced to branch out into other segments of the hobby market. To this end, Testor began producing static scale models of popular aircraft out of pinewood. These scale models proved enormously popular, and enabled Testor Corporation to survive, despite its inability to produce its flagship chemical products in any significant quantity. On February 1, 1944, a fire broke out at Testor's main Rockford facility. In addition to totally destroying the upper two floors of the four-story brick building, production lines and equipment suffered severe damage from both the fire itself and from the water used to douse the flames. Total damage was estimated at over US$200,000; however, in less than a year a new, larger plant was built and production continued. With the end of the war, the company was able to resume production of its trademark glues and paints, including adhesives for the plastics that were quickly becoming popular. Additionally, surpluses of ultra-lightweight balsa wood left over from the war enabled the company to begin producing flying wooden aircraft models as well as provide raw balsa wood for builders of custom-designed models.
Acquisitions and partnerships
In 1949, Nils Testor began talks with Charles Miller, president of Duromatic Products, regarding a possible partnership. Duromatic was the manufacturer of the McCoy hobby engine, a popular motor for self-propelled models. These talks culminated in a joint marketing agreement of the McCoy engine with Testor model airplanes, as well as an agreement for each company to design its respective products to be interoperable with those of the other. By the 1960s, plastics had risen to prominence in American life, including the hobby industry. Almost all model kits on the market were plastic, necessitating paints and glues different from those used for wooden models. Although Testor had been producing such chemicals since the 1940s, it had resisted producing plastic model kits for quite some time. However, the company could not stick to its tried-and-true line of wooden models indefinitely, and so in the early 1970s it purchased IMC and the Hawk Model Company, both well-respected manufacturers of plastic model kits. Later that same decade, the Italian model kit manufacturer Italeri was acquired, further expanding Testor's line of plastic model kits, usually repackaged with photographs rather than paintings on the box. In 1984-1987, Testors sponsored a video series "Adventures in Scale Modeling". The program featured half-hour segments on detailed model building with an on-location shoot featuring the item being modeled. The shows were produced by WSWP-TV.
F-19
In January 1986 Testors released a model kit of a hypothetical F-19 Stealth Fighter, designed using open source intelligence before the real F-117 Nighthawk was introduced. Although it was very different from the actual plane, video games and many other toys and models were inspired by this fictional design. Many features, such as canted fins were used on the Nighthawk and other subsequent stealth designs. A Soviet fighter would be produced as well.