About making a water tower boiler and pump in brass.
The order of assembly is critical. A proper order minimizes the chance of breaking welds already made on some extremely small parts.
Before we start, watch this video of an operating HO scale steam engine.
As you work on small brass projects, think through how you will make each part and make a jig.
Order of assembly.
Cut out .2mm brass to be used for the boiler.
Make the access door out of 2 mm brass. Tin both sides. Make sure you leave only a fine film of solder. Too much solder will cause you to have too much cleanup.
Make boiler straps by hammering .9mm brass wire flat. Solder the bottom three in place on the boiler. Be sure that you have them placed so that you can add the access door.
First tin the boiler where all the straps will go. Also tin the inside edges of the top and bottom of the boiler. Thin tine where the straps go and fairly thick on the inside edges.
Then tin the straps.
Solder the straps in place using a lot of heat. A quick pass with a torch works well. But be sure to use a wet cloth placed over completed joints to act as a heat sink.
The fourth strap will be added after the boiler top is soldered in place.
Roll the boiler around a wine bottle cork or other jig sanded to size. Solder the joint.
Shape the boiler door using another wine core or bolt. You can use bending pliers or tap it with as hammer. Just give it enough bend to fit the shape of the boiler.
Solder it in place using a lot of heat. Again a torch is best.
Cut out the top. Use .2 or .3 mm brass. .3 mm is better because it gives you more to which you can attach the top strap,
Cut out or punch the center plate for the top. See video on DIY metal punch. Tin both sides.
Tin the inside boundary of the top. A fairly heavy coat is good here.
Tin a small spot in the center of the top where the center plate will go.
Solder the center plate to the top.