14 Cabin Interior Murphy’s law

Описание: The SAR Garratt 400 class
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MUSIC by Peder B. Helland
licenced by soothingrelaxation.com

Last not least a big “thank you” for my outstanding translator Paul!




Transcript:
14 - Cabin Interior - Murphy’s law


…and this other story starts with the assembly of the firebox!
Just as for the live steam version of the engine, the firebox should be made out of a brass cast.
The possible size of the cast parts is limited, so the box has to be made out of several parts.
The parts get positioned and connected together at different welding points.
I chose silver solder in order to keep the soldering areas mostly invisible.
All that went quite well, however, there were some deformations of the flat areas that couldn’t be avoided.
As a relief, I wanted to only cast the front and rear sides of the firebox
and do the rest out of brass sheeds. Thus, I printed several new parts.
In order to print the surfaces flat, the parts are placed upside down on the printing table.
The rear wall is split because the middle part exhibits a slight inclination.
The wax parts get glued to create a cast tree. Now Murphy’s law struck!!!…:
Apparently the temperature for the cast was too low and the walls of the parts were designed too narrow.
As a matter of fact, with these sober experiences we go back to the printer.
With fundamentally redesigned cast connections and wall sizes this time everything went well! Now the usual post-processing and preparation for the polishing is done. The newly added parts are cut out of 0.5 mm brass sheets and drilled accordingly.
The biggest indication instrument of the cauldron has a diameter of 7mm. The area is therefore relatively small for a splitting. With according auxiliary tools the first try works fine. The rotation axis of 1mm diameter was a little bit too big. I replaced it by a broken 0,6mm drilling bit, of which I had several piled up.
As the axis of the pointer an M 0.6 screw is used.
The cast of the various small parts as for the water level indicator worked perfectly.
Murphy’ s law thus went on hold….!!!
Because this Garratt was fired with oil, the hatch to the burning chamber was actually a small observation hole, while the valve bodies get cast and the hand wheels are aced out of 0.5 mm brass sheets.
After a series of failures at the beginning of this building group a test assembly with the burner unit feels really good!!!