Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Thanks for the comment, Richard. You guys' encouragement really helps to keep the project going.

SIGHT GLASS

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One of the things I was most concerned about was the sight glass. This engine has one of those fragile, U-shaped sight glasses. I was relieved when a pressure test indicated that there were no significant leaks. With that happy discovery, it was time to do a preliminary steam-up. I filled the boiler with hot water, lit the burner, and waited patiently...

Soon enough, the pressure had just about reached the operating range, when STEAM AND HOT WATER began spewing from the lower sight glass fitting! Not only that, the rain of boiling water was directly in front of the firebox door, so I was unable to shut down the lamp! [ Guests cannot view attachments ] (Unfortunately, video camera was not running!) After the initial panic subsided, I opened the whistle valve to drain off the excess pressure, and managed to staunch the leaking fitting with a hand towel, at least long enough to snuff the flame. Lesson learned: Just because a fitting doesn't leak under air pressure doesn't mean it will hold up against pressurized BOILING WATER.

Well, there was no avoiding it now. I would need to disassemble the sight glass, and see if I could come up with a way to reseal the fittings. I was a bit worried that the attempt to remove the U-shaped glass might crack or break in the process. I know that some of the sealants used back in the day would harden over time, and be difficult to remove. As it turned out however, disassembly went smoothly, and I was able to get the parts cleaned up and assess the situation.

(to be continued...)