Flaring tube ends after expanding?
Flaring tube ends after expanding?
I've read here a number of times how expanded in-place copper tubes in a steel boiler move over time. What are people's opinions on slightly flaring the protruding tube ends after expanding to stop or slow the movement?
Edit: This is my second boiler build, my first was welded copper with silver soldered tubes. Expansion and contraction of the tubes wasn't a concern.
Denny
Edit: This is my second boiler build, my first was welded copper with silver soldered tubes. Expansion and contraction of the tubes wasn't a concern.
Denny
"Measure twice, curse once."
- ChuckHackett-844
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Re: Flaring tube ends after expanding?
My understanding is that, when the tubes are properly rolled with a tube roller, they are slightly expanded on both the inside and outside of the tube sheet thereby locking them in place.
Regards,
Chuck Hackett, UP Northern 844, Mich-Cal Shay #2
Owner, MiniRail Solutions, LLC, RR Signal Systems (http://www.MiniRailSolutions.com)
"By the work, One knows the workman"
Chuck Hackett, UP Northern 844, Mich-Cal Shay #2
Owner, MiniRail Solutions, LLC, RR Signal Systems (http://www.MiniRailSolutions.com)
"By the work, One knows the workman"
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Re: Flaring tube ends after expanding?
I don't think it's worth it. In fact, I don't see how flaring the end will keep the tube from growing. I have tried several ways of fastening tubes - silver soldering, swedging, urethane expanders. I now use a commercial roller with lubricant and leave them as rolled. I roll them as lightly as I can to get them to seal. I do not anneal the tube beforehand. I'd rather go back and re-roll a weeping tube rather than over-roll.
The growth I've noticed doesn't seem to hurt anything.
The growth I've noticed doesn't seem to hurt anything.
- Bill Shields
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Re: Flaring tube ends after expanding?
No....flaring will not have any effect on this.
At best, flaring will improve the flow
At best, flaring will improve the flow
Too many things going on to bother listing them.
Re: Flaring tube ends after expanding?
just learning how to roll tubes - you don't anneal first? Just got a tube roller
- Bill Shields
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Re: Flaring tube ends after expanding?
Some do, some do not.
As soon as you start to roll, the annealing is out the window anyway
Some say that it helps to keep from cracking tubes
As soon as you start to roll, the annealing is out the window anyway
Some say that it helps to keep from cracking tubes
Too many things going on to bother listing them.
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Re: Flaring tube ends after expanding?
I found it easier to roll after annealing.Bill Shields wrote: ↑Sat Feb 11, 2023 4:42 pm Some do, some do not.
As soon as you start to roll, the annealing is out the window anyway
Some say that it helps to keep from cracking tubes
But I also know I reduced the coppers strength by 10x (apparently 600psi crush pressure vs 6k) if data material sheets are to be believed.
-Chris Srch---- Home track Tradewinds and Atlantic Railroad
Re: Flaring tube ends after expanding?
There shouldn’t be problems with cracking, unless the tubes are over-rolled, which reduces their thickness. I followed Marty’s recommendation of making the holes in the rear tube sheet the same size as the o.d. of the copper tubes, and the front sheet 0.005” oversize. Tubes were not annealed before rolling. After rolling, none leaked.
Incidentally, I have seen tubes that began to leak “heal themselves” without needing to be re-rolled. Evidently, the leak between the copper tube and the steel tube sheet became filled with rust after a few months.
Incidentally, I have seen tubes that began to leak “heal themselves” without needing to be re-rolled. Evidently, the leak between the copper tube and the steel tube sheet became filled with rust after a few months.
Dan Watson
Chattanooga, TN
Chattanooga, TN
- Bill Shields
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Re: Flaring tube ends after expanding?
Absolutely true on what fender said - been there done that.
FWIW:
a seriously under rolled tube will leak like a geyser and generally require rework.
after rolling, I generally put a couple of psi air in the unit and soap it with a brush.
FWIW:
a seriously under rolled tube will leak like a geyser and generally require rework.
after rolling, I generally put a couple of psi air in the unit and soap it with a brush.
Too many things going on to bother listing them.
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Re: Flaring tube ends after expanding?
Not to hijack this thread but what manufacturer tube roller is best to roll copper in a steel boiler. I am going to need one and request recommendations.
- Bill Shields
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Re: Flaring tube ends after expanding?
Lest cost
I use Wilson and / or Elliott -> but hang on to $$
There are many manufacturers, but if you are in the boiler or hex business, there are the GOTO companies, and have been for decades.
You first need to know tube dimensions as well as clearance to closest obstruction.
What is the center distance from any tube to the closest anything that can get in the way of inserting the roller.
Generally the smokebox end is not as much trouble as the firebox end
I use Wilson and / or Elliott -> but hang on to $$
There are many manufacturers, but if you are in the boiler or hex business, there are the GOTO companies, and have been for decades.
You first need to know tube dimensions as well as clearance to closest obstruction.
What is the center distance from any tube to the closest anything that can get in the way of inserting the roller.
Generally the smokebox end is not as much trouble as the firebox end
Too many things going on to bother listing them.
Re: Flaring tube ends after expanding?
Something to consider if space is tight.
Pictured below is my commercial roller and my homemade roller, both fit 1/2" K copper tubing.
The home built roller doesn't have many clearance problems. They seem to work equally well.
Pictured below is my commercial roller and my homemade roller, both fit 1/2" K copper tubing.
The home built roller doesn't have many clearance problems. They seem to work equally well.
"Measure twice, curse once."