Boiler Material for Large Scale Model Engines

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MattMaie

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I'm interested in building live steam model engines, with an emphasis on traction engines. This is a question directed at people who have built traction engines and locomotives before. For those of you who have built large (for my purposes, 1/4 scale and above) steam powered models. What kind of steel did you use to ensure that a boiler was made that was safe to operate and would pass inspection?
 

Jasonb

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Isn't this just the same question you asked last week which will risk getting all teh same answers again here.

Do a search for "Rumley" on here and there is quite a bit of talk about the boiler on that model including what steel was used. BUT he lives in a state that has quite relaxed codes, you may have to work to stricket codes as mentioned in your other thread.

J
 

RonGinger

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What kind of steel did you use to ensure that a boiler was made that was safe to operate and would pass inspection?
If you are in the US there is no material YOU can use to make a boiler that will pass inspection. A boiler that will pass inspection can ONLY be made by a shop with an ASME code stamp. No home built boiler can be even inspected, that can only be done in a code shop.

There is far more to a code stamped boiler than a final inspections. The design must be inspected and approved first, then at 2 or 3 stages of construction, at the inspecting agents choice, there are inspections. Every piece of material must have a full paper trail leading back to its certificate from the manufacturer. As each piece comes into the shop it must be stamped with id numbers that trace back to the shop records. At the final inspection the inspector will sample several pieces of the boiler, finding the id stamp and asking to see its paper trail. The actual inspection and pressure test of the boiler is the shortest, almost an incidental part of the. inspection.

I did a lot of volunteer work at the Boothbay RR Shop as we built the boiler for #9 at the WW&F Ry. I was present for several of the inspections and at the final inspection when we got to swing the hammer to put the stamp into the boiler It gave me a good understanding of the process.

Also you usually cannot run a boiler of any size bigger than a model in public. unless it is a code stamped boiler. So a 1/4 scale engine will not be allowed to run at any engine show or event that the public can attend- only in your own back yard.

Its a tough set of rules, but boilers are bombs. They need to be treated carefully.
 

Entropy455

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Ron, you have peaked my curiosity.


I am going to call theWashington State department of Labor and Industries later this morning, and ask them how I may go about certifying a home-made 125-psig “power boiler” for a 1/4-scale locomotive.


I was flipping through the Washington State code this morning (http://apps.leg.wa.gov/RCW/default.aspx?cite=70.79)& (http://apps.leg.wa.gov/WAC/default.aspx?cite=296-104) and with regard to ASME requirements - the law states that the boiler must beconstructed to ASME standards. I don’t however see anywhere that an individual constructing a boiler must be certified in his abilities to followthe ASME. There was mention that NDT inspections by non-L&I inspectors (hydro, RT, UT inspections, etc) must be accomplished by a State certified shop.


It’s my understanding that you build the boiler, and then pay the fees for the L&I inspections - then they certify the boiler for use. I’ll let you know what they say.


On a somewhat related note – several years ago I built an equipment trailer. In order to get a title, I needed to provide receipts for the construction supplies (steel, axles, lights, wire, etc), and also have the trailer inspected by the State Highway Patrol. This is a security preventative measure, used to prevent theft of trailers (the rebadging of vins). Anyway, the officer asked me who welded the trailer together. I told him I did. He said that only a Washington State Certified welder may assemble a trailer. He said that home-made trailers fall apart on the freeway, and that he’s not going to sign the paperwork. I was completely stuck.

I told the officer that I was a Mechanical Engineer, and that I had taken several welding classes in college, and that these welds are sound. He said that if I provided transcripts to him, and showed him that I had taken formal welding classes in college, that he’d sign the paperwork. Thus I did, and things worked out.


Nonetheless, I think this was a BS requirement, and the officer was making up rules on the fly. I searched and searched through the Washington State Codes, and the only reference in requiring state certification for welders, was for large public safety projects (inpsected and approved by state-licensed engineers), like bridge construction, and steel building construction, etc.

A boiler requires hydrostatic testing, which will prove the welds. You cannot hydro a bridge or building.

Again, I’ll let you know what L&I says.
 
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Entropy455

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Here’s what the inspector said.

In Washington state, a “power boiler” must be constructed by either an M-stamp, or an R-stamp holder (M-stamp is a state licensed manufacturing facility, and an R-stamp is a state licensed repair facility - either may construct a boiler from scratch).

In addition to the stamp, ASTM boiler grade steel (with certification paperwork) is required for the construction process. Non-boiler rated steel, although technically acceptable, is not permitted for legal quality-control reasons. Again, you must provide material certification paperwork for the steel being used - and ASTM boiler steel comes with that certification paperwork. Fabrication welds must be accomplished by a State licensed welder (with welding certifications provided). Hydrostatic testing must be accomplished within a licensed M-stamp or R-stamp facility.

I asked the guy if there was any way that I could build one in my garage, and get it certified by L&I (with me being a non-state certified welder).

The answer was yes: I must build two identical boilers (using ASTM boiler steel), and pay to have an M or R shop destructively test one of them. Then the other boiler may then be “blessed”after passing hydrostatic testing. It’s considered a manufacturing “batch-sampling”certification process. The other option is to build one boiler (using ASTM boilersteel), and pay an M or R shop to 100% RT inspect every weld. Needless to say, both options are cost-prohibitive when compared to simply having an M or R shop build you a boiler.

If you hold a state welding certification, things get much easier. You simply build the boiler, take it to an M or R shop for hydrostatic testing, and they can legally throw a stamp on it, as if their shop accomplished the welds.

Operating a non-licensed power boiler (over 15 psig) in Washington State will result in steep fines.

Well, that pretty much clears up any and all grey-areas. . . . . . If you want you build a functional boiler powered locomotive, you’ll likely want to farm-out the boiler construction portion of work.
 
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scooterman

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There is a saying 'There is no substitute for practical experience' and I would think this is very applicable to boiler making! If you do not have the experience in the construction of boilers, do not attempt to build one, all it takes is a small mis-step, flaw, in construction or materials, combined with the unlimited potential of steam, the word 'BOMB' comes to mind!!!! There are numerous makers of boilers for the hobbyist, these people have built boilers of all sorts of requirments for the customer,are licenced and can pass any and all ASME testing for the application, be it railroad,steamboat, traction engine, etc. With the cost of material's this day and age and the 'required equipment' to produce a boiler, it doesnt equate to a 'home built' one. You may find some recorded disaster's about boiler explosions on You-Tube, just my thoughts on the subject!
 

chrsbrbnk

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Every state is different in its approach to code and boiler size, in general the states that do not require a FULL code astm shop built boiler TEND to allow models with a restriction on boiler barrel dia. fire box area and grate area. Say for instance dia under 16" and under 2 square ft in the fire box. Look in the code data in the sticky. the wording is critical, a model boiler may not be the same as hobby boiler and would be different than a historical boiler These wording differences determine hugely the whole process.
That said then there is running at an particular show' for this you need to pass the shows inspectors (not a state inspection but often done by a state inspector) So in this type of inspection you would likely need to show an approved safety valve, two methods of supplying feed water. believable construction techniques and welding. a fusible plug. correctly placed sight glass. working pressure gage. correct piping schedule for pressure most often schd. 80 piping and fittings and valves. Sometimes your required to show liability ins. or operating skill say steam school certificate.
The point is if you build the traction engine boiler with the standard code material and procedures and construction methods your self you won't have a" CODE" boiler but you may not need to. Go to some of the big steam shows like rollag or Mt pleasent all most all the models are not code certified boilers a reasonable guess would be that there are at least 100 1/2 , 1/3 , and 1/4 scales out there. some slightly more attractive than others.
So on smoke stak in the model engineering forum under.. started work on my 1/3 scale case is a long thread on building a 1/3 scale 1915 case 65 hp steam tractor with a lot of material descriptions and build process stuff ect.
Keep in mind while these model boilers do have very serious possibility's if you screw up I have heard a single serious injury failure of a model boiler .... Chris
 

rrsteve

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I realize this is late, but I just read the above interpretation of the Washington boiler statutes. It did not ring correct with me, because while I live in Maryland, I own a miniature locomotive that was formerly under insepction in Washington state, and I used the original Washington state paperwork to qualify the boiler under the Maryland rules, which are quite similar. The key regulation is this one:
http://apps.leg.wa.gov/RCW/default.aspx?cite=70.79.070

RCW 70.79.070

Existing installations — Conformance required — Miniature hobby boilers.


</B>(1) All boilers and unfired pressure vessels which were in use, or installed ready for use in this state prior to the date upon which the first rules and regulations under this chapter pertaining to existing installations became effective, or during the twelve months period immediately thereafter, shall be made to conform to the rules and regulations of the board governing existing installations, and the formulae prescribed therein shall be used in determining the maximum allowable working pressure for such boilers and unfired pressure vessels.

(2) This chapter shall not be construed as in any way preventing the use or sale of boilers or unfired vessels as referred to in subsection (1) of this section, provided they have been made to conform to the rules and regulations of the board governing existing installations, and provided, further, they have not been found upon inspection to be in an unsafe condition.

(3) An inspection certificate may also be granted for miniature hobby boilers that do not comply with the code requirements of the American society of mechanical engineers adopted under this chapter and do not exceed any of the following limits:

(a) Sixteen inches inside diameter of the shell;

(b) Twenty square feet of total heating surface;

(c) Five cubic feet of gross volume of vessel; and

(d) One hundred fifty p.s.i.g. maximum allowable working pressure, and if the boiler is to be operated exclusively not for commercial or industrial use and the department of labor and industries finds, upon inspection, that operation of the boiler for such purposes is not unsafe.

Steve
 

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