Light

In 1937 he started at Light, being influenced by the engineer Billings^[7] where he got involved in the Cubatão Hydroelectric Power Plant project.^[4][5] During his time at Light, Arena also worked as an industrial parts designer.^[8] His time at Light also influenced his choice of employees and the development of his didactics, by liking to help others to progress.^[9]

Termomecanica

After several years in Light, without a dazzle of evolution^[5] and inspired by working with his father on metal selling,^[10] he came to resign. In 1942, with US$200 that he had received from the company, he founded Termomecanica São Paulo SA,^[4] which started in Mooca, manufacturing the first electric bakery ovens in Brazil,^[4] subsequently achieving success on the market with the recycling of non-ferrous scrap metals^[4] with its greatest creation being the production of the bronze alloy TM 23,^[5] which until today is one of the most used in the Brazilian industry.^[11]

At the end of World War II, Arena multiplied the capacity of its company by buying second-hand equipment from the US.^[8] In 1950, he created a continuous casting process.^[12]

In 1957, he became a naturalized Brazilian.^[13] In the district of Rudge Ramos, São Bernardo do Campo, was the place where, in the 50's, he started the manufacture of its new factory, which came to focus on the diversified production of non-ferrous metals.^[4][5] For the transition of the country's economy from agricultural to industrial, this was a very promising time.^[8] The rapid and disorderly development of the region in São Bernardo do Campo caused the appearance of several favelas and, after studying the conditions in which these people lived (mainly suffering from malnutrition), he began to hold the free lunch, the sending of end of year gifts, school uniforms and later these social works centered on the Salvador Arena Foundation, founded in 1964.^[14] As an employer, Salvador offered basic food basket, medical care, an additional year-end supplement even before the thirteenth salary was created, and also granted profit sharing.^[4][8] Due to his wage policies and aversion to the state monopoly, Arena was seen as a socialist, or as Jorge Andrade said: "an open liberal who became a millionaire in capitalism".^[15]

In the 60's, Termomecanica was responsible for building bodies of the rockets for the CTA, wheel hubs for the Buffalo airplanes, which served isolated communities in the Amazon and in the 90's was involved in the production of the Piranha missile, the first air-to-air missile built in a third world country.^[16]

Being innovative, Arena has become one of the richest entrepreneurs in the country. Having fought for a change in the Brazilian teaching method,^[4] developed suggestions that were not accepted by the government because of the high investment required.^[4] He founded the Colégio Termomecanica in 1989, which uses his teaching method developed in the 1970s,^[4] that had been refused by the Brazilian^[5] and British government.^[17] The school has become an educational symbol in São Bernardo do Campo. According to the 2010 and 2011 ENEM, the school ranks first in teaching quality in the great ABC.^[5]

As a professional, Arena was influenced by Henry Ford and used to dedicate hours to an idea^[18] and was extremely active in his factory, controlling resources to avoid waste, besides always being the first to arrive and the last to leave.^[19] In his quest to avoid waste and reduce costs, he reused discarded machines and refurbished them so that they had an efficiency comparable to state-of-the-art machines.^[20] He also operated his business in his own way and was an open critic against the government, even in the Brazilian military dictatorship, and in 1987 he even took a strike against the "political and economic trickery of the country".^[21][22] Arena was also accurate in paying taxes^[23] and trained his own staff to ascend to management positions.^[24] Its wage policy, which aimed at improving the living conditions of its workers, went against the dictatorship's policy of accumulating capital.^[25]