Abstract: A method and apparatus for fusing adjacent surfaces of a pair of separate bodies made from thermoplastic, fusible material in which a heating device having a pair of mutually moveable parts is employed, each moveable part defining a heating surface that may be heated by heating means, there being pressure sensing means arranged between the mutually moveable parts of the heating device whereby the so-called bead-up pressure may be measured and controlled independently of the varying drag pressure, the heating device being arranged between opposite ends of the bodies or tubes to be fused, the body surfaces being forced into abutting engagement with the heated opposite surfaces of the heating device, the heating device being removed from the heated surfaces of the bodies when the heated bodies are heated to the desire degree, the heated bodies then being forced into mutual engagement to cause fusion of the bodies to one another.