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Author Topic: Boiler stays  (Read 1866 times)

kiwimodeller

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Boiler stays
« on: February 19, 2018, 09:23:53 pm »

Hi, a friend is building a 7" x 4" center flue horizontal boiler and would like some recommendations for the stay sizes and material. We are presuming that two stays will be enough as the flue will also act as a stay and thought we would use 1/4" copper rod but would welcome some input. Thanks, Ian.
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mrsgoggins

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Re: Boiler stays
« Reply #1 on: February 19, 2018, 11:48:30 pm »

I used 2 stays on my 4.5" dia centre flue but found that the endplates distorted locally at 200psi during test. I cured this by adding a girder stay. I think KN Harris's book gives guidance on stay spacing. I normally use drawn bronze rod for stays.
Ironically I am in Christchurch at the moment but all my literature is back home in the UK so I can't provide any more detail.


Regards,
Keith
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pendlesteam

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Re: Boiler stays
« Reply #2 on: February 20, 2018, 08:46:26 pm »

It is completely down to what thickness material you are using, the diameter of your flue and what pressure you need to run your engine at. A D10 in a reasonably sized tug will run at 15psi if set up correctly whilst some of the older enclosed high speed motors can run at 60 psi, either way you need only test to 120psi.  The calculations for stay pitch and diameter are on the web if you google it and are easy to apply.
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steamboatmodel

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Re: Boiler stays
« Reply #3 on: February 21, 2018, 02:48:07 pm »

K. N. Harris's books are on line in PDF form.
Gerald.
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