For further testing a heat resistant electrode holder is needed which can handle the temperature of multiple hundreds degrees while staying cold enough to be mounted on 3D printed parts.
So here is my attempt of building one.
It's made off a cross fitting, hose connectors, hydraulic fittings and a brass tube, what keeps the electrode holder water thight while offering space for the tungsten electrode.
The plan is to keep it cold by a constant water flow through it. Maybe by using some thermal paste it could also keep the electrode a bit cooler. The electrode is loose inserted into the brass tube. There should be around 0.3mm of space between electrode and the inner wall of the tube.
The electrode could be fixed by a clamp at the upper and lower end of the brass tube.
The X Carriage for scale. All parts are 1/8" BSP size. Only a 3D printed mounting bracket and a hose connection is missing.