Slight technical problems...

I disassembled the slide valves for servicing, and found that the valve seats, made of gauge plate steel (approx 1% carbon) were severely corroded after less than two months in the cylinder. Before shooting this image, I polished the insert for about 15 minutes, first with 240, then 600 grit emery. The pits are several thou deep, and didn't go away with this polishing.

I've used ordinary synthetic motor oil for lubrication, which probably is the cause of the problem - the oil absorbs water and emulsifies to a whitish goo, which won't protect the steel.

I have saved the brass steam port inserts I originally made, but since brass against bronze isn't supposed to be good, I tried gauge plate instead - with this problem!

I'll try using the brass inserts next time, and see how well they fare. Fortunately, the bronze valves hadn't worn much - a minute of polishing on fine emery got them nice and shiny ahain.

Also, the wire mesh of the poker burners has deteriorated quite badly - it appears that inside the flues, the flame tends to burn more at one end, closer to the inlet. The stainless steel mesh there had become "woolly" in appearance, and is very brittle - it crumbles when touched. Further to the front, the mesh is in good condition. The picture shows the worst part - it looks like the stainless steel has somehow separated into the alloy elements, perhaps the shiny, woolly stuff coating the wire is chrome, and what's left in the brittle wires is the iron?

The tube itself has also deteriorated badly, softened by the heat it even bent, and shed off quite a lot of scale (chrome?) - only half the thickness of the metal left!

I will have to experiment more to get the pokers burning more evenly inside the flues, and perhaps try some ceramic material, such as kaolin wool, instead of the wire mesh.

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