I have read this part of your message several times, whilst thinking about the practicality of doing the same thing in our sizes. The biggest problem I can see is fitting the tubes to the firebox. At best, there is little space to work there, and with the firebox assembled, it would be VERY tricky. Apart from that, I cant see any disadvantages, but also dont think there is any great benefit. Alan ----- Original Message ----- From: "R.L. Roebuck" <rlr20@xxxxxxxxxxxxxxxx> 3) In looking through a book detailing full size boiler construction, it looks like it was common place to construct a subassembly of inner and outer firebox all on one piece with backhead the throatplate fitted. Then as the final stages of assembly the boiler barrel, front tubeplate and tubes would be added. Why do we not do this in miniature? Am I missing something here - as we end up having a much larger mass of copper hot for the fitting of all the stays, all the backhead bushes, foudation ring etc, whereas with the full size method they keep the size of the 'beast' down for all the fiddly bits, right up till the end of the job? Rich. MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.