Calling Marty Knox

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jscarmozza
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Calling Marty Knox

Post by jscarmozza »

Marty,
Attached is a photo of my buddy's Tom Thumb boiler, you'll notice the large bulge on the water jacket; our question is, can this section be cut out and patched, or should this boiler be heading for the scrap pile? This engine was probably running at NJLS when you were there, after my buddy bought it, he was cleaning and inspecting it and found the problem with the boiler. We'd like your opinion, thanks.
John
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Marty_Knox
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Re: Calling Marty Knox

Post by Marty_Knox »

First, is this copper, or steel? It's hard to tell from the picture.
Is there any way to look inside?
jscarmozza
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Re: Calling Marty Knox

Post by jscarmozza »

It's a copper boiler Marty, I should have said that in the original post. Yes there are some potential access points. One of the guys at the club has an inspection scope, I think we'd be able to borrow it and fish it in to look around a little, what would we be looking for?
John
Marty_Knox
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Re: Calling Marty Knox

Post by Marty_Knox »

A buildup of scale or some other reason for the bulge. I suspect someone may have got carried away with a hydro.
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Bill Shields
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Re: Calling Marty Knox

Post by Bill Shields »

easier to build a new boiler than fix that..
Too many things going on to bother listing them.
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gwrdriver
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Re: Calling Marty Knox

Post by gwrdriver »

My thinking is this occurred while it was having extreme localized overheating, which could have been caused by several things, the obvious reasons (low water, too much fire, etc), and as Marty mentions a buildup of scale which prevented water from reaching the area. I doubt it was an over-zealous test as I would have expected a burst (split) in a flue, or at a joint or seam, before a tube wall deformed that much.
GWRdriver
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NP317
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Re: Calling Marty Knox

Post by NP317 »

My reaction on inspecting the picture was:
Scale buildup on the water side. Under pressure and heat it bulged.
Time to replace the boiler, if it was mine.
RussN
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Bill Shields
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Re: Calling Marty Knox

Post by Bill Shields »

find out when you cut it apart....
Too many things going on to bother listing them.
jscarmozza
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Re: Calling Marty Knox

Post by jscarmozza »

Yeah, we were pretty sure the boiler was unsalvagable. Not that I'm a boiler maker, but I thought it was odd that there were no stay bolts in the water jacket area. Thanks for the replys. John
James Powell
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Re: Calling Marty Knox

Post by James Powell »

There don't need to be any stays in a round surface, typically...the thickness of the round surface has to be able to take the hoop stress, but there is no need for stays, which renders "Marine type" fireboxes far easier to make...

That being said, I would recommend cutting apart this boiler to figure out what went wrong. I suspect that there is scaling in between the two surfaces.

James
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Bill Shields
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Re: Calling Marty Knox

Post by Bill Shields »

stays in the water jacket are not needed (in any of the Tom Thumb boilers I have built).

Yes, the wrapper does have a calculable crush pressure, but it is well over 150 PSI...

put the boiler in a band saw and saw it in half
Too many things going on to bother listing them.
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Bill Shields
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Re: Calling Marty Knox

Post by Bill Shields »

You never know what you will find...
bottom back mud ring area.jpg
firebox.jpg
mud ring.jpg
Too many things going on to bother listing them.
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