Regions 106 which can be regarded as being monocrystalline are formed locally by irradiating with laser light, and at least the channel-forming region 112 is constructed using these regions. The inventive device and method are characterised in that an on-board camera and pyrometer are used to measure the properties of the jet and the temperature of the deposit on the part and in that the correction to be made to the supply parameters of the torch is deduced. In the barrel, the temperatures of each parts are controlled by a temperature control section. Included in the present invention is an autocorrect circuit that limits the frequency response of the eletromagnetic induction coil. The support structure is produced by first bending the central section of a metallic support member into a U-shape, placing the bent member on a specially designed adjustable jig, and attaching a cross arm. The combustible gasairsteam mixture is ignited for burning in the atmosphere above the exit opening.