[Pauli]

At 18:20 in this video

about building a Princess Royal Class locomotive in 1951 (and actually the same footage is used in another video about a 1935 build of another class) the use of aluminium foil as part of the insulation of the boiler is shown, and mentioned as "remarkable".

I did not know of this real life practice, but did exactly the same with my Aster P8, having the usual ceramic felt insulation as first layer, and then wrapped that in aluminium foil - "shiny side in" - as to reflect and lessen radiant heat loss.

This practice of mine has been either scorned or disregarded with a frown, some even claiming it can't work. Wich makes no sense to me, since coffe thermose's obviously work this way.

So I find some satisfaction in learning that it was used in live-size real locomotive boiler insulation practice.

For the model builder, it has the advantage of not adding any space requirements, so adding that reflective foil layer is very simple. I hold it in place with paper tape during assembly. I figure, if the paper somehow incinerates, it won't smell or cause problems.

 

[SRC Steamer]

Pauli,
-- I think you are quite correct in your assumptions about using aluminum foil to retard radiant heat loss from boilers etc., To what degree this may be effective in our small boilers is open to question. Using such should at least provide some protection, it's also simple, why not use it?? Thanks for the good idea!!
--When we owned 1950 era autos with carburetors, sometimes the carburetor & fuel pump fuel lines would overheat from the motor and cause a "Vapor Lock", so the motor would stall until those lines were cooled-off. We sometimes used a wrapping of aluminum foil on the underhood fuel lines to help circumvent this problem. Consider also that certain types of building construction use foil on insulation panels, furnace ductwork, as well as attic insulation between the ridge rafters, etc.
Best Regards, Ken