The fourth heating starts as usual with fluxing the boiler. Stuart then heats with the propane torch continuing to apply more flux as necessary.
The second set of side stays hang by their heads. The backhead stays are positioned by the backhead which is a light press fit into the boiler shell.
When the firebox side of the second set of sidestays has been soldered, Stuart moves onto the outside of the first set of sidestays. When completed the boiler is stood on it's backhead to give access to the firebox side of the firebox side of the backhead stays then the throatplate stays on the outside.
The second set of side stays are at the bottom Stuart fluxes the boiler
Stuart starts on the inside of the second set of side stays
Not very sharp, but it does show the fumes containing cadmium
Next Stuart reheats before starting the outside of the stays soldered at the last heat
Note how the solder is applied to the stay off the side sheet & out of the flame
Next Stuart reheats prior starting the backhead stays
Progress is orderly, though he does not hang around, there is no sense of being hurried
Note the boiler is propped on U section steel to clear the backhead rivets
Reheating before starting on the throatplate rivets
After soldering one or two rivets, Stuart decides he needs more heat
The solder stick is applied to the front of the rivet, the flame is behind it
Side stays. The phosphor bronze expansion brackets were fitted to and soldered with the side stay tails. The surface finish is from the brass brush I used with a Proxon drill to clean up
No 2 boiler On number 1 boiler, dirt stopped the silver solder
penetrating the countersink for the top left hand rivet
The bottom left stay, where the solder penetration looks suspect,
was redone from the inside at the next heating