Converting a Baldwin 2-4-2 LYN to a Baldwin 2-4-4

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Pipescs
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Re: Converting a Baldwin 2-4-2 LYN to a Baldwin 2-4-4

Post by Pipescs »

Morning

That is a good question. No the operating pressure will be 125 on the first safety and 130 for the upper safety. All future test will be at 200 psi.

Having watched the testing of various new boilers on their initial pressure checks they have all been taken to 400 no mater what the future operating pressure. I believe the logic is sound, in that, if you are going to snap a stay, or have a leak, it is best to do it in the shop early on.

I do not believe there are any specific specs that call for this. No other reason than to ensure my welds are going to hold.

Interestingly when I ran it up to 200, I can no longer see the weeping. I am told it may rust shut with time.
Charlie Pipes
Mid-South Live Steamers


Current Projects:

Scratch Built 3 3/4 scale 0-4-4 Forney
Little Engines American
20 Ton Shay (Castings and Plans Purchased for future)
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LVRR2095
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Re: Converting a Baldwin 2-4-2 LYN to a Baldwin 2-4-4

Post by LVRR2095 »

The usual standard for an initial test is twice the working pressure to avoid putting undue strain on the boiler. Subsequent tests are to one and a half times working pressure.
I have never seen anyone test to 400 psi.

Keith Taylor, Jefferson, Maine
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Re: Converting a Baldwin 2-4-2 LYN to a Baldwin 2-4-4

Post by Berkman »

Full size locos are tested as per FRA guidance to 1.25X operating pressure.

You might want to run it at 130-135 for a bit drier steam and more margin of error on firing it.
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NP317
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Re: Converting a Baldwin 2-4-2 LYN to a Baldwin 2-4-4

Post by NP317 »

Same question here. 400 psi?

The Washington State boiler code for hobby boilers specifies that 400 psi constitutes "over pressure damage".
That limits the final allowable operating pressure, because it assumes the pressure vessel was damaged by that high psi squeeze.
Whether or not we agree it was damaged, The State declares it so.

A 200% of Maximum Allowable Operating Pressure (MAWP) hydrostatic test is specified as correct.
Food for thought.
RussN
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Pipescs
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Re: Converting a Baldwin 2-4-2 LYN to a Baldwin 2-4-4

Post by Pipescs »

All said above acknowledged. Appreciate the inputs. Pressure test is completed after I let it sit for an hour the gauge held.
You might want to run it at 130-135 for a bit drier steam and more margin of error on firing it
I have not bought the safeties yet so I will take your advice and try it.

Hoping everyone out there is having a safe Christmas Season and hope you are all healthy.

Charlie.

PS. Will be working on the Shay boiler this next few days to start finishing the parts for it.
Charlie Pipes
Mid-South Live Steamers


Current Projects:

Scratch Built 3 3/4 scale 0-4-4 Forney
Little Engines American
20 Ton Shay (Castings and Plans Purchased for future)
Berkman
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Re: Converting a Baldwin 2-4-2 LYN to a Baldwin 2-4-4

Post by Berkman »

I've ran several engines that were set at 135psi -150psi or so for the low-pressure pop valve. The steam is a bit drier, but it's a whole lot easier to recover steam pressure from 120psi back to 140 psi than from 100 psi back to 120psi. Setting it at the higher pressure also gives you a much wider "band" of peak power where the engine will run at peak performance.
Pontiacguy1
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Re: Converting a Baldwin 2-4-2 LYN to a Baldwin 2-4-4

Post by Pontiacguy1 »

I have my safety valve set on 130 and 135 on my 2-10-0, and I've found that it runs better there. For whatever reason, if you can keep it above 100 PSI, it will build steam very fast. If you let it drop off below 90, it seems to take a lot longer to build your pressure back and you have to add water in fits and spurts. The locomotive just seems to be easier to run at a slightly higher pressure, so I run it there.

Charlie did the 400 PSI test because that's what I did when he watched me do a hydro test. I do 400 PSI on a new boiler (3x MWP) I do 300 PSI on a repaired boiler (2 1/2x MWP). I'm in Tennessee, not in Washington state. These are all welded steel boilers with rolled in copper flues. If they can't stand a 400 PSI initial hydro test, without something leaking, bulging, cracking, etc... then I must have done something wrong. On subsequent annual hydro tests, I usually take it to just about 200 PSI (1 1/2x MWP), and let it go at that.

I can definitely see that you Do NOT do anywhere near that high of a test on a full-size boiler or on a copper boiler or anything similar to that. These locomotive boilers are really hugely over-built and an initial test to 3x MWP shouldn't hurt anything. I remember Gene Allen telling me a story one time that a guy that was quoting building some boilers for him told him that he could certify them up to 750 PSI if he wanted him to! Do whatever makes you feel the most comfortable, and you definitely have to conform to your state's regulations.

Not trying to start an argument, just explaining what I do.
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Harold_V
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Re: Converting a Baldwin 2-4-2 LYN to a Baldwin 2-4-4

Post by Harold_V »

I would think that the limiting factor on test pressure would be how much pressure the copper tubes can withstand before deforming. That information may be available, and should be a guideline as to how much can be applied before damage to the tubes could be expected. Assuming that's true, it would be wise to avoid approaching that amount of pressure, which would damage the boiler when lower pressure would not.

H
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NP317
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Re: Converting a Baldwin 2-4-2 LYN to a Baldwin 2-4-4

Post by NP317 »

What Harold said.
And equally important are your local pressure vessel laws. They define the applicable limits, regardless of physics.
RussN
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Pipescs
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Re: Converting a Baldwin 2-4-2 LYN to a Baldwin 2-4-4

Post by Pipescs »

Morning everyone,

I can tell I have started an interesting conversation. So I will address a few concerns.
The Washington State boiler code for hobby boilers specifies that 400 psi constitutes "over pressure damage".
That limits the final allowable operating pressure, because it assumes the pressure vessel was damaged by that high psi squeeze.
Whether or not we agree it was damaged, The State declares it so.
The state of Alabama Code does not address a "Hobby Boiler"

Realizing a Hobby Boiler can be anything from a 15 PSI Welesco Boiler or 60 PSI Stuart Models Hobby Boiler there is no simple statement to address what will damage a boiler on its initial test. For instance I would never go over one and a half times on any of the above boilers as 200 PSI would destroy them. Also I would not take my LE American to over 1.5 operating pressure.

The Rustbucket boiler was designed (By me with a lot of help from this group) under Alabama Code Exemption. As I am an overthinker and worry wart, I did find a copy of the Alabama Code prior to considering the idea of building the boiler

I will also say that in no way are our boilers Hobby or Toy Boilers.

This exemption under Alabama code states that there is no licensing or annual requirements for:

a: boilers under 5 cubic feet of volume and operating at 250 psi pressure.
b: One and one half cubic feet in volume and 600 psi pressure.
c. An inside diameter of six inches with no limitations on pressure.

The Rustbucket boiler falls under provision A. It was designed to operate at 130 psi with a volume of a little over 4 cu ft.

More importantly when I laid this boiler out I did not simply sketch a design that would fit.

After I came to a size and shape and a proposed working pressure of 130 I worked backwards for an engineering safety factor of 10. This meant everything in the boiler had to withstand 1300 psi. Especially the stay bolts lay out.

For the calculations I used the very good tool worked out by the The Maryland State Boiler Inspectors and the Chesapeake & Allegheny Live Steamers. NOTE: I chose to work with them as Maryland does have a requirement for annual state inspection on boilers at their club site and charges $29.00. Its all about the tax. On their site below you will find the software to design a boiler to meet the Maryland code .

The main reason I spoke with the Maryland Boiler authority was to verify that they would be willing to come to the track on a three day notice to run a boiler test on my engine should I haul it there to run. The Baltimore club informed me that this was indeed a requirement. I have spent a lot of my weekends there and cannot recommend a better bunch of steamers.

http://calslivesteam.org/calboil1.htm

My only concession on the project was my giving up on finding Pressure Vessel rated steel plate in my area. Understanding I would have to buy the "whole sheet", when I asked the local yards to order it, I was told that my one sheet did not meet their suppliers minimum requirements.

This lead me to find that most boilers in our "Hobby" are not made of certified steel.

Boiler Tube: 10 inch, 3/8" wall thickness, Seamless, A36, (allowable working pressure 5000 psi) I was told the markings on the pipe indicate it was an older PV standard. Not sure I believe it.

Fire Tubes: Copper tube - Type K , yield strength S = 10000 psi (69GPa) for drawn tube. Working Pressure, 1424 psi, Rupture Pressure 9840 psi

Firebox/Throat/Side Sheets: 3/8", A36,

Tube Sheets 1/2" A36

Stay Bolts: 7/16" A36: (Note: Spaced as per the CAL worksheet to ensure a safety factor of 10 for 1300 PSI.

For better or worse she is done. Will she rust out earlier due to the A36. With luck I might live long enough to see it.

I will repeat part of a conversation I had with the Maryland Boiler Inspector 5 years ago. My boiler will not pass the inspection as it has rolled tubes not welded steel. So I will get an exemption. He explained that his office had no problems signing off on coppertube boilers as the roll in point on the fire box tube sheet was a natural fail point which made them safer. The roll in point getting hot and cold is the first part to go and that allows water to blow out the fire long before the main structure fails.

Thanks for the continued help.
Charlie Pipes
Mid-South Live Steamers


Current Projects:

Scratch Built 3 3/4 scale 0-4-4 Forney
Little Engines American
20 Ton Shay (Castings and Plans Purchased for future)
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NP317
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Re: Converting a Baldwin 2-4-2 LYN to a Baldwin 2-4-4

Post by NP317 »

Charlie:
You are definitely on top of the requirements for your boiler projects.
And your description of your process will be useful to anyone following your footsteps.

I wish I had your welding skills to make a boiler. Most impressive!
RussN
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Dick_Morris
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Re: Converting a Baldwin 2-4-2 LYN to a Baldwin 2-4-4

Post by Dick_Morris »

If you are looking at bumping up the boiler pressure take a look at the pull available at the wheels versus the maximum that can be developed at the draw bar. If the pressure is too far out of balance the engine will end up slippery and consume excessive water and fuel. Comparing it to commercial designs may not be that productive. When I was deciding on the bore for my Consolidation several years ago I looked at a number of designs and found their bore was typically larger than necessary.
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