I think some live steam models are using copper firetubes and boilers, the demands are not as hard than for a full sized engine. I rather doubt any full sized engine will use copper. Show me exceptions tho.

M Austin,

I support you 100%

The miniature locomotive community on Chaski had a long thread on this a few years ago and the consensus arrived at was that the ASME regs state that you can use copper tubes, as long as the boiler is built to meet its requirements for lengthwise staying without using the tubes as part of the calculations.

The opinion being that the ASME will not let copper be relied upon to provide any of the staying strength, so they (copper tubes) can not be calculated as part of the strength of the boiler. They can be used, just not calculated as part of the strength of the boiler.

Check out this post, it has attached clippings from some ASME codes. http://www.chaski.org/homemachinist/vie ... tubes+ASME

There are also many other posts covering copper tubes on Chaski.

I would really like to have copper tubes in a future locomotive boiler project.