dizzysteamer:122632 wrote:Having never built a loco I joined a 16mm group on Yahoo for any help and advice i may need and share my work with whoever i am having absolutely no luck trying to post anything with them😕 I have no idea if its down to me or its just a clicky group.
The problem is likely to be Yahoo, as there are continuing issues with people on other groups not being able to post for no apparent reason.
I've seen posts from you on the group, so some are getting through. I only read the group online, by logging into Yahoo. The user interface is awful, but I don't seem to have problems posting.
It's certainly not an exclusive group, it even lets in ex-colonials like Dave and I.........
It's worth persevering. You have to be logged into Yahoo anyway, to see the group files, photos and message archive.
dizzysteamer:122632 wrote:
My question is the book says the crush pressure for 1.2 mm wall thickness is 1150 lbs/sq inch however if i use the domestic water pipe at .8 mm wall thickness........
As Dan said, 0.8mm would still be strong enough for a boiler working at 40psi.
I'm not familiar with UK model boiler testing and design rules. The Aust. AMBSC copper code, calls up a min. wall thickness of 0.9mm (20g) for a 15mm flue tube, for working pressures of 60-100psi. Martin Evans also calls up 20g for a 5/8" flue.
Roger Melton at Just the Ticket Engineering lists 5/8" x 20g copper tube.
http://justtheticketsupplies.co.uk
It has a slightly larger OD than your water pipe, but looking at the photos. it wouldn't be difficult to modify the tubeplates to fit at this stage, if you want to use a heavier tube.
Here in Oz, I've got the opposite problem, most copper tube is 16g (1.6mm) in the sizes I use and it's hard to find even 18g (1.2mm). I had to import some copper tube recently for a small boiler that needed shell and flue sizes that are no longer sold here.
Regards,
Graeme