A lip pen assembly includes a container and a lip pen is removably inserted into the container. The method begins with abrasive blasting of the groove surfaces, followed by closing of the open groove ends by build-up welding, and subsequent filling of the grooves with soldering powder. The turn tank has drain grooves each extending from a forwardly or rearwardly outer end of each of the tube insertion holes for discharging condensation water to below the turn tank therethrough.