Runner
Well-Known Member
- Joined
- Feb 10, 2011
- Messages
- 124
- Reaction score
- 17
Hi all,
I thought I knew the purpose of the crown stay, i.e to prevent deflection of the top of the boiler barrel and/or deflection of the top of the firebox. My Martin Evans design has the crown stay rivetted and silver soldered between the firebox top and the boiler barrel, however I have seen a Martin Evans design which shows that the crown stay doesn't touch the boiler barrel. It therefore wouldn't prevent deflection of the boiler barrel. Maybe I need clarification on the purpose.
Secondly, what is the preferred method of assembly of the boiler, particularly in relation to the firebox stays? Martin Evans for my locomotive says that the firebox stays are the last operation, i.e after the foundation ring and backhead are silver soldered. However I have followed the very interesting post "Making a boiler for a 3.5" gauge locomotive" where the firebox stays are completed before the foundation ring and backhead are installed. This method allows access between the inside of the boiler barrel and the outside of the firebox to apply silver solder to both sides of stay as it passes through the boiler barrel and the firebox. Effectively four silver solder operations per stay. For my sequence of boiler construction, you would be unable to see the penetration (if any) of the solder into the gap between the barrel and firebox. Martin Evans recommends the use of caulking solder for the stays, which is not soft solder but a high MP solder. I have silver soldered 3/4 of the foundation ring, but not the backhead. I prefer to use silver solder for the firebox stays but because of the foundation ring prevents access to most of the forward firebox stays between the barrel and firebox, should I silver solder the stays before the backhead and what steps should I adopt to ensure penetration through when having access to only the indside of the firebox and outside of the barrel.
Regards
Brian
I thought I knew the purpose of the crown stay, i.e to prevent deflection of the top of the boiler barrel and/or deflection of the top of the firebox. My Martin Evans design has the crown stay rivetted and silver soldered between the firebox top and the boiler barrel, however I have seen a Martin Evans design which shows that the crown stay doesn't touch the boiler barrel. It therefore wouldn't prevent deflection of the boiler barrel. Maybe I need clarification on the purpose.
Secondly, what is the preferred method of assembly of the boiler, particularly in relation to the firebox stays? Martin Evans for my locomotive says that the firebox stays are the last operation, i.e after the foundation ring and backhead are silver soldered. However I have followed the very interesting post "Making a boiler for a 3.5" gauge locomotive" where the firebox stays are completed before the foundation ring and backhead are installed. This method allows access between the inside of the boiler barrel and the outside of the firebox to apply silver solder to both sides of stay as it passes through the boiler barrel and the firebox. Effectively four silver solder operations per stay. For my sequence of boiler construction, you would be unable to see the penetration (if any) of the solder into the gap between the barrel and firebox. Martin Evans recommends the use of caulking solder for the stays, which is not soft solder but a high MP solder. I have silver soldered 3/4 of the foundation ring, but not the backhead. I prefer to use silver solder for the firebox stays but because of the foundation ring prevents access to most of the forward firebox stays between the barrel and firebox, should I silver solder the stays before the backhead and what steps should I adopt to ensure penetration through when having access to only the indside of the firebox and outside of the barrel.
Regards
Brian