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

RE-ATTACHING BOILER TO FIREBOX

When received, this engine's boiler and firebox were separated. I have seen various manufacturing methods used for joining a vertical boiler to its firebox, including a separate roll-formed ring which traps formed flanges on both parts, a rolled flange on one part formed around a rolled flange on the other part, etc. This was the first instance I've seen which used soldered tabs.

Notice in the following picture of the Carette firebox, how there is a nickel-plated ring which has been rolled and crimped to a formed flange on the firebox:

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Also notice the arrows indicating two of three tabs (one of the tabs is not visable in this view), which are also part of the nickelled ring. The tabs are formed in such a way as to contact a circular flange at the base of the brass boiler. The view shown in the picture below is the same firebox looking from the bottom (the cast iron base has been removed):

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Here is a picture of the lower flange of the boiler. The arrow in indicates one of the three spots where the tabs were originally soldered. You can just make out a slightly tinned area. There are two more like this, equally spaced around the rim.

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Re-attaching the boiler to the firebox is a matter of assembling the two parts, radially aligning them in the original position (sight glass directly above firebox opening), inverting the assembly, and re-soldering the three tabs. This is not quite as easy as it sounds, and I don't have any pictures taken during the process (my hands were full at the time!) I elected to use a propane torch and StayBrite silver-bearing solder, with the assembly inverted. This requires that the torch be upended somewhat to enter the firebox bottom opening, and a typical propane torch is not designed to work in this attitude. I wound up using a "TurboTorch" attached to a small propane tank. This is quite a handy item for soldering, where you need to maneuver the torch around to various angles:

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I have the torch attached to a one-gallon size propane tank (holds around 11 lbs. of gas):

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This worked out pretty well. Here is a view looking in from the bottom of the firebox:

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I put the three black marks on the boiler bottom to help me line up the two parts before soldering. I got a bit too much solder on one of the three joints, as you can see on the finished assembly:

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It's not too noticeable, though. At least the two parts are one again!

Paula