Paul
Active Member
Posts: 28
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Post by Paul on Aug 2, 2024 8:54:39 GMT
I have a commercially built and certified boiler for a 3 ½" Hall. I need to fit a tube through the boiler for the blower valve feed, which at present only has the two ends of the boiler with PB bushes. I have two lengths of copper tube, one with walls too thin to take a thread and the other with thick walls but only a 1/16" bore.
Before I start to make some PB fixings to silver solder at each end of the thinner tube to take a thread, would a 1/16" bore tube be adequate for the blower to function adequately?
I would appreciate any advice from those who have the knowledge and expertise that I lack.
Paul
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millman
Part of the e-furniture
Posts: 324 
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Post by millman on Aug 2, 2024 12:29:27 GMT
Someone brighter than me will give you all the maths but gut feeling says it is a bit small, I personally would go for the larger bore and make some fittings as you mention. I wonder what bore size LBSC and other designers specified?
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Post by John Baguley on Aug 2, 2024 23:01:56 GMT
For 2½" Gauge at least, LBSC specified 3/16" od tube by 16swg wall so that would only be around 1/16" bore. I would think that would be adequate for a blower feed for a 3½" loco as well?
I make all my longitudinal stays with bronze end fittings anyway as I don't particulary like threading copper tubes.
John
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uuu
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Post by uuu on Aug 3, 2024 16:01:26 GMT
The Tich "large" boiler has a 5/32" blower tube specified - so this might be smaller bore - alas the drawing doesn't show the thickness, and I've not got the words.
Wilf
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Post by cplmickey on Aug 25, 2024 8:24:10 GMT
Looking at the Hall drawings the blower valve has a drilling of 3/32 so perhaps 1/16 is a bit small although as has been said before, you don't need a huge blast to draw the fire. Ian
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Paul
Active Member
Posts: 28
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Post by Paul on Sept 1, 2024 7:48:31 GMT
Thank you for the replies. I have decided to route the pipe somewhere along the outside of the boiler, as lining up threads and feeding the tube past stays has proven to be difficult if not impossible. It is a pity that a pipe was not included as part of the boiler construction.
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Post by jo479 on Sept 27, 2024 18:17:55 GMT
I made a mistake on my 5"G Princess of Wales Boiler and couldn't feed the blower tube past the Firebox so I had to use one of the stainless boiler handrails as a Blower Tube 1/8" OD, inner dia was about 1/16" definitely no bigger, has worked fine for 25 years
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