< Perfection >
White lettering on black body naturally looks neat. I tried to do it on the side plates and the air containers with following tools.
- ALPS MD-2000J: Thermal head printer.
- CD-Master: Master film which can be patterned by thermal printer (option of "Print Gocco").
- High Mesh Ink: Pasty ink (option of "Print Gocco").
- Squeegee: Plastic plate to squeeze ink through the film (option of "Print Gocco").
I employed MS-WORD to prepare letters. Then the master film was patterned with the printer. After that, the film was floated on the side plate with a cardboard spacer. Pasty ink was mounted on a side of the film. Then, with a squeegee, the ink was spread on the film. As a result, the ink was squeezed onto the side plate through the film. In case of failure, the ink should be immediately wiped out with spirits. Slight residue can be deleted with a blow of aerosol black paint.
The air container has curved surface, so the master film cannot be floated. So as to prevent ink leakage, the film should be stretched tightly.
After printing, the letters were stoved with an infrared heater, so as to enforce its adhesion. Don't stove too hot, otherwise the letters become yellowish.
Next I tried to make etching plates from 1.5mm brass sheet. Masking procedure is the same as the lettering. Surround and back side of the plate are covered by adhesive tape. The photo shows block copy on a paper and a brass sheet ready for etching. Note the pattern includes cutting lines for sawing.
The etchant is for printed circuit board, or ferric chloride liquid. Etching depth can be monitored with a small piece of the same brass sheet with its one side covered by the adhesive tape. It took 2.5 hours to etch 0.2mm at room temperature. The liquid wastes should be neutralized before disposal. I have to mention that the ink I employed was not suitable for masking, because it leaves tiny pin holes after the etching.
After etching, each plate was sawn out and finished with files. Then very shallow hole was end-milled on back side of the plate, and a screw with thin flange was silver-soldered in it. The photo shows how to mount a number plate on the smokebox door. Note additional two studs which hold the upper two corners of the number plate.
The surface of each plate was painted, red for the number plate, or black for the company plate. In case of the smokebox plate, the back side was also painted black. Then the surface was polished out with emery cloth on a surface plate. Finally, whole job was coated with clear lacquer, so as to prevent darkish of the brass letters.
Final assembly was done. The side tanks were bolted down to the running boards through washers pasted with plumber's joint. All of screws were
tightened with Loctite 222.
After six years of endeavor, the locomotive was completed at last!
I will introduce the details in next time.