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

DIY Boiler Build Questions

Advantageous to have the 5/16" copper pipes silver soldered in like position A or B?
Would B allow water to enter in the lower end and rise up to the higher end easier?
(They won't of course all be in the same line as shown in the drawing)

Extend them how far out from the exhaust stack? I don't see any advantage to having them as long as pictured.
Just protruding half an inch out from the stack should be enough?


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Horizontal would be easier to get a good seal as round pipe and round holes.
 If on a slope  then round pipe and have to make holes oval

Thanks Dennis, makes total sense mate.
Any advantage to going horizontal and putting an upwards and downward bend on each one after soldering?

Bonjour Tony,

Here is our our French Manufacturer JMC makes an horozontal boiler (see at 5')
The boiler is 2 mm thick and the inside pipes 1 mm (6 x 8 mm), I let you convert in inches  :

Drilling oval holes for sloped thermic syphons isn't much of a problem if you make yourself an angled drill guide. The oval holes also provide a greater surface area for solder bonding, not that our relatively low-pressure boilers are in need of that bonus bonding.