Edward (Ted) Buckland Firth and Guy Mortimer (Tony) Firth, the founders of Firth Industries, were born in Auckland on 27 September 1905 and 15 April 1907 respectively. They were the younger sons of Edward (Ned) Thompson Clifton Firth, a manufacturer and inventor, and his wife, Blanch Emily Banks. Their paternal grandfather was the entrepreneur and pastoralist Josiah Clifton Firth. Both boys entered King's College at the age of six, Ted completing his secondary schooling in 1922 and Tony in 1924.
On leaving school Ted Firth commenced a course of engineering studies; Tony became a farm cadet in the Gisborne district. In 1925 Ned Firth asked his sons to join him in a business to manufacture a new type of domestic-laundry boiler, made of pumice concrete, which he had patented. A small plant was built at Rangiriri, Waikato, and a company was established under the name Ironclad Products.
Both Ted and Tony Firth were over six feet tall, alike in appearance, but quite different in personality. Ted, retiring by nature, became the firm's design engineer, while Tony, outgoing and sociable, became sales director. At Rangiriri they worked together to devise production methods, make the moulds for the pumice-concrete boilers, and laboriously assemble the finished product by hand. Then Tony took to the road by bus and train to sell the Ironclad boiler to hardware merchants throughout the Auckland region. Their elder brother, the Auckland photographer Clifton Firth, designed the firm's distinctive symbol, an armoured knight on horseback.
In the late 1920s Ted and Tony began an association with aviation which was to continue for more than 20 years. They learned to fly at the Auckland Aero Club and gained their private pilot's 'A' licences in 1930. The following year they both won prizes in events at the club's sky pageant at Mangere airfield. In 1930–31 the brothers joined the New Zealand Air Force (Territorial) and were commissioned as pilot officers. Ted was promoted to flying officer in 1933, and they both qualified as instructors. When the Waikato Aero Club was founded in 1931 they became members, and later instructors. Ted was highly skilled in aerobatics and often put on a great show for Sunday visitors to the aerodrome; Tony, too, often demonstrated his outstanding ability as a pilot.
Meanwhile, Ironclad Products made slow progress during the depression, and it was not until 1932 that the firm took on its first employee. In 1934 its name was changed to Firth Concrete Company and the following year a new factory was established at Frankton. The range of products was increased to include concrete blocks, fence posts, farm troughs and laundry tubs. The first Labour government's public works schemes and state-housing projects created increased demand for concrete products and modest growth continued through the late 1930s. In 1937 net profit on trading was £884 and the two directors were receiving a weekly wage of £7 10s. Two years later the first branch factory was established in Stratford.
On 22 April 1936 Tony Firth married Alison Thorne George at St Mark's Church, Remuera. They were to have two sons and a daughter. On 9 December the same year Ted married Mary Gwendoline Martyn at St Andrew's Church, Cambridge; they were to raise a family of three daughters and one son. Both couples established homes in Hamilton.
On the outbreak of the Second World War in September 1939 Ted and Tony Firth immediately joined the Royal New Zealand Air Force. As experienced club pilots and territorial officers their skills were urgently needed as flying instructors. In July 1940 both were promoted to flight lieutenant, and over the following years served at various RNZAF stations including Whenuapai, Blenheim, Harewood, Ashburton and Wigram. In June 1942 Ted Firth was awarded the Air Force Cross, and the following month both brothers were promoted to squadron leader. Ted became chief flying instructor at the Elementary Flying Training School, Harewood, where trainee pilots remembered him as an intimidating presence, demanding explanations for heavy landings and other faults in their flying. Tony became flight commander at Wigram, and he too demanded high standards. Years later one of his pupils still remembered his valuable advice: 'don't think you are a better flier than you are'.
In July 1944 the Air Board approved Ted Firth's request for a transfer to the reserve so that he could return to the business, which his father, now aged 77, had been managing since the outbreak of war. A month later Tony was appointed commanding officer of the RNZAF station at Norfolk Island; he remained in the air force until October 1945. During the war the firm continued to prosper, particularly through military contracts. The post-war period offered new opportunities, and in two decades of rapid growth 10 new branches were opened.
After the war the Firth brothers resumed their involvement with the Waikato Aero Club, both serving as instructors, committee members and club president. They also found time for other interests: Tony was a talented golfer and an expert trout fisherman, while Ted developed a strong interest in conservation. In the 1950s he and his wife bought a run-down property at Te Pahu, on the lower slopes of Pirongia Mountain, part of which they developed into a successful economic unit, running sheep and cattle. The remainder, an area of recently cut-over bush, was set aside to regenerate. In 1977 they donated a 5.2-hectare block of regenerating native bush to the Royal Forest and Bird Protection Society of New Zealand, and established the E. B. Firth Trust to support conservation initiatives. After Ted's death a further 16.2 hectares was covenanted under the Queen Elizabeth II National Trust. A commemorative plaque on a large rock at the entrance to the reserve was unveiled in October 1991.
In 1972 Tony Firth retired as joint managing director of Firth Industries due to ill health. Ted continued as head of the firm, but in 1977 he was involved in a car accident from which he never fully recovered. He died in Hamilton on 6 May 1978, survived by his wife and children. Tony died at Hamilton on Boxing Day 1980, also survived by his wife and children.
From small beginnings at Rangiriri, Firth Industries had become one of New Zealand's most successful industrial firms, largely through the creative leadership and technical, management and marketing skills of its directors, Ted and Tony Firth. Although the company was taken over by Fletcher Holdings in 1979, the Firth name was retained, a fitting tribute to two of Waikato's most enterprising and innovative industrialists.