The exhaust mixer has both hot exhaust and hot water passing through in seperate ports
. I noticed a sheet of gasket material at the local auto parts
supplier that is the same as auto exhaust gaskets are made out of, it is a sandwitch of metal foil and something heat proof in the middle then indented with a regular pattern. It could be similar to head
gasket material. What do you think of using that with some of the sealants.
Levelling the surface is certainly on the cards as the exhaust mixer need machining in any case due to some slight distortion from expanding alloy corrosion
in the old joint.