More than 90 years of experience make us an expert in the bending industry. From the foundation of “Karl Theis Kupferschmiede und Apparatebau” in 1926 to the product extension by manufacturing half tubes in the year 2006: The company experienced the war years as well as economic highs which means that it has experienced a lot. Come and have a look at the exciting history of our company! 



  • 1926-1945


    In the year 1926, Karl Theis took the decision to leave the coppersmith’s workshop Jost Theis & Co, founded in 1904, in which he held a great share, and to set up his own business. On 1st December he founded his own coppersmith’s workshop at Charlottental, Weidenau.

    At the location Charlottental, the company mainly produced coppers and boilers. After having relocated the company to Bruchstraße at Siegen-Weidenau in 1935, the production programme had been extended comprising at that time heating batteries, heating coils made of steel and copper, copper boilers as well as tube bundles and spiral tubes.

    In 1945, the factory was completely destroyed in a bombing raid. Karl Theis provisionally rebuilt the factory and during the difficult period after the year 1945 he produced hand-forged craft products up to the time when the economic recovery enabled him to resume the actual production activities.

    1926     Foundation of “Karl Theis Kupferschmiede und Apparatebau” by Karl Theis at Charlottental

    1935     Relocation of the production activities to Weidenau, Bruchstraße

    1945     Complete destruction, reconstruction

  • 1958-1983


    Post-war reconstruction of the company was followed by a continuous enlargement of the production programme which contributed to a continued growth of the company. Ernst Eibach’s joining the company represented the next generation.

    In 1958, the company Karl Theis KG was founded, relocating the company to Siegen Geisweid “Auf der Setze”. The newly built workshop with an office building at Weidenau, Herrenwiese had been the company’s registered office since 1962. The main products were heating coils and heating batteries made of copper and other metals. From 1970 onwards, the company produces bent tubes for the chemical industry and apparatus engineering.

    Ernst Eibach, the company founder’s son in law, had worked with the company since 1955. In 1963 he took over the management of the company. After converting the company Karl Theis KG into the company Karl Theis GmbH in 1980, he has been the company’s Managing Director and Karl-Heinz Gronwald joined the managament. In 1983 a new era started when purchasing the first segment bending machine.

    1958     Relocation to Geisweid “Auf der Setze”         

    1959     Foundation of the company Karl Theis KG

    1962     New construction / relocation to Weidenau, “Industriestraße 15”

    1970     Start of producing bent tubes for the chemical plant construction

    1980     Start of producing bent tubes for the chemical plant construction

  • 1988-2016


    During the 90 years of its existence, the company has been able to continually develop and grow. The tradition and the continuity of the family company as well as its continuous readiness to innovate are important factors for the success of the company along with the commitment and the know how of its staff members.

    In 1988, a new storage and despatch building was put into service, enabling the company to manufacture half tubes. Purchasing a profiling line for manufacturing straight half tubes represents a further decisive enlargement of the production programme in 1992. In 1996, Klaus Eibach joins the management of the company, continuing the tradition of the family company. Equipping boiler bottoms and cones with half tubes for the first time is realised in 2005 when purchasing 2 production halls with open space on 10,000 m² in total at the new site “Breite Straße/Untere Rolandstraße”.

    In 2008, they start building a further production hall. After having purchased the company ETU Rohr GmbH, they produce heat-exchanger U-tubes at this site. In 2012, production was ceased at the former site at “Industriestraße” and also relocated to the new halls. Nowadays, our main focus is an innovative further development mainly in the field of half tubes.

    1988     Putting into service the new storage and despatch building, start of producing half tubes

    1996     Klaus Eibach joins the management

    2000     Renting an additional production hall at the site “Breite Straße/Untere Rolandstraße”

    2005     Purchase of 2 production halls and open space (about 1o,ooo m2) at the site „Breite Straße / Untere Rolandstraße "

    2008     Erection of a new production hall, acquisition and implementation of the company ETU-Rohr GmbH

    2009     Purchase of further production and office space of about 7,000 m²

    2012     Relocation of the production activities from Industriestraße 15 to the site „Breite Straße /Untere Rolandstraße "

    2013     Innovative further development by means of a half-tube bending-machine developed in-house

    2016     90th anniversary of the company

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