boiler leak

[Bill DawesParticipant @billdawes]

The continuing saga of my Emma Victoria build (now 12 years in the making)

Some time ago I reported that the boiler failed a pressure test, just a couple of tiny leaks, one on the outside of the firebox at a joint the other inside the fire box between inner wrapper and end plate.

Hate resoldering but eventually gave it a go which cured the problem but created two others inside firebox. (liberally coated all joints and rivets with flux) Now dreading even more the thought of another reheat.

I am wondering if Comsol might be the answer but concerned about two things, is melting point of Comsol high enough for use in  the firebox and as it contains lead will that prohibit any future silver soldering exercise.

Bill D.

[Nick HughesParticipant @nickhughes97026]

Hi Bill,

the answer is Yes to both questions.

[noel shelleyParticipant @noelshelley55608]

I would not use comsol or a soft solder on a boiler inside or out. IF there has been ample flux then several causes come to mind, both involve heat, or the lack of it. Either the heating was to slow and the flux became exhausted or that there simply was not enough heat to allow the solder to flow properly. Once partly soldered the joint will need more heat and lots of it quickly to repair the joint. This is where oxy fuel equipment comes in handy. A bigger burner and a good brazing hearth may be needed. Packing round the boiler to conserve heat with ceramic fibre or charcoal will help. Good Luck. Noel.

[duncan webster 1Participant @duncanwebster1]

Unless you have enough heat to get the whole boiler pretty hot, trying to repair silver soldered joints can be a nightmare. Uneven expansion can cause more leaks. Don’t ask how I know. Alec Farmer’s book recommends Comsol for situations like yours as long as the boiler is structurally sound, just a small leak. Most important, discuss with your boiler inspector first

[Dave HalfordParticipant @davehalford22513]

You can also cause leaks by cooling too quickly.

[Clive Brown 1Participant @clivebrown1]

Silver soldering inside the firbox with air/propane isn’t really a runner without a very large amount of heat and insulation and, even then, probably will result in chasing leaks as you have found. That leaves oxy/gas or comsol as possibilities.

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