hallo Simon
yes theirs that to ,,which has to be taken in consideration , its always best to
err on the thicker size ,,,by getting other peoples thoughts every-one will have
a good idea of what is acceptable... i myself want to be in the British guide
lines ....i will be using 2mm and three mil thickness,,, over engineered maybe
at least ..i can prove to the boiler inspector it will be on the right side also
it will give me more weight (tractiv effort) some lighter engines suffer
problems like ,,,that even the frames will be1/8 steel ,,, in other words built
like a brick dunny,,,i know the tubing that you are referring to its plentiful
here and can be bought by the meter thanks Simon i am getting a good picture
built here of what's acceptable
Charles in oz

----- Original Message -----
From: Simon Wass
To: halfinchlivesteamforum@...
Sent: Wednesday, May 14, 2008 7:57 AM
Subject: Re: [Half inch live steam forum] Re: question on boiler material


I'd always thought the reason for thicker plates was the unsupported areas
you tend to get with the back, throat & smokebox tubeplates. A backplate can
have big (ish) areas where there are no stays, the throatplate needs to be
thick if using the Curly method of a butted join (I use a full flanged
throatplate and think I'd be ok with 16swg but still use 13!). I'm sure what
I've built in this sort of model size (Tich, Invicta & Scotsman) all use
16swg for all inner firebox plates? Not got a model or their drawings to
hand though! For my tubes, I use 10mm microbore household plumbers pipe, not
sure of its swg? A 10m roll is very cheap (for copper!).

----- Original Message -----
From: "John Baguley" <baggo@...>
To: <halfinchlivesteamforum@...>
Sent: Monday, May 12, 2008 8:54 AM
Subject: [Half inch live steam forum] Re: question on boiler material

> Hi Charles,
>
> I am not sure if there is actually a spec laid down over here for
> metal thickness versus boiler size. However, the 'standard' seems to be :
>
> barrel, wrappers, and crown stays - 16swg (1.6mm)
> Smokebox tubeplate, throat plate, backhead, firebox plates - 13swg (2.5mm)
> Tubes - 18swg or 20swg (0.9/1.2mm)
>
> For a small boiler you can get away with 16swg for the throat plate,
> firebox tubeplate and firebox door plate. Makes flanging the plates
> much easier as well. I've read that the only reason for using 13swg
> for the backhead was that LBSC used to thread his fittings straight
> into the copper without using bushes and the thicker metal gives more
> thread. I would not recommend that practice nowadays though!
>
> John





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