I started with the barrel for the boiler some time ago, now I needed a firebox for the Burrell traction engine.
The basic design is to have a simple copper cylindrical boiler and a firebox where the end of the boiler is located.
The heat is then applied to the underside of the boiler cylinder and through the flue pipes.
The plan is to use a simple methylated spirits burner.
The bulkheads for the firebox were machined from 1/8″ thick mild steel. The outer shell/wrap around this uses a 1.8mm thick mild steel. I machined a piece of round steel to match the diameter of the firebox bulkheads. I then started to bend the flat plate around this cylindrical former.
As you can see below I used a G-clamp to keep the plate tight to the former and then clamped the sides in a vice, thus bringing the sides tangential to the former.
After releasing the part from the vice I carefully pushed the sides together, keeping the G-clamp in place.
The outer shell fits nicely to the bulkhead. Note though that I’m using an engineers clamp to pull the plate onto the top of the bulkhead.
I soon realised that I needed to clamp the firebox in two directions to close all of the gaps of the shell to the main plates.
I pickled all of the parts for around 30 minutes before rinsing and drying.
Not sure how well this worked. There were a number of bubbles on the surface of the steel, so some form of reaction was taking place.