All,
What products are being used today for lagging an active locomotive boiler. As the C&NW #1385 is brought closer to steam-up we want to consider all possibilities.
What are you folks using?

Thanks...............mld

CONGRATULATIONS, sounds like you're getting there Pete,

Unless they've thought of something better since the last time I lagged a boiler, get you some calcium silicate blocks. They can be secured with agricultural baling wire, or fencing tie wire, until you get the jacketing wrapped around the boiler and tighten the clamps. This type of wire is very tough.

VIVA C&NW #1385 !!!

At my former employer, we were very satisfied with a fabricated framework floating on the boiler to support the jacket with 3-1/2" fiberglass bats without backing paper between the jacket and boiler. One time only, at the insistence of the customer we used block insulation. It was a horrible labor intensive ordeal, and we all unanimously agreed that we were never going to do that again.

And we used calcium silicate blocks along an 18" wide section along the top of the boier to allow workers to walk on this area without caving in the jacketing, Everything else, including the steam dome, was insulated with your regular 3 1/2" fiberglass insulation that was held in place with soft mechanical wire while the jacket in installed.

To each his own, but that fiberglass itches like Hell !!! Not only that but it's rather messy to re-use. With block insulation you can make a fitted mat that you can remove and re-install easily, although it is time consuming the first time around.

Which ever type of insulation you choose, MASK UP. Either calcium silicate dust, or teeny little pieces of fiberglass are very hazardous to your health if inhaled.

4-6-2 S.P. 2472 experience:

In 1991, we followed S.P. practice, except that we used calcium silicate blocks instead of asbestos. We put heavy wire bands around the boiler, made "T" shaped wire clamps, and installed rings of calcium silicate blocks. The firebox, which had lots of flexible staybolt caps, required lots of mud made from calcium silicate chunks. After installing all the blocks, everything was plastered with calcium silicate mud for a nearly-airtight thermal seal.

The backside of many calcium silicate blocks had to be cut or countersunk to fit over rivet heads, boiler seam doubling plates, studs, etc. (Note that C&NW 1385's new all-welded boiler has a much smoother exterior surface than S.P. 2472's riveted boiler.)

Advantages:
We could walk along the top of the boiler and/or climb up the boiler sides to manually fill the sand dome and oil the bell trunnions, without denting the boiler jacket.

Great thermal insulation: On Sunday afternoon, the crew had the boiler full to the top of the sight glass, and full 210psi pressure, before shutting off the oil fire and shoving the engine into the enginehouse with a giant forklift. The next Saturday morning, we'd still have 20-25psi steam pressure. After pulling the engine out of the enginehouse, we had enough steam to run the atomizer, blower, and tank heater. No need for that $#%@ noisy diesel air compressor (Golden Gate Bridge painting crew discard, would never meet modern noise requirements) to light off.

Also, the insulation kept the boiler jacket at a warm but not hot temp.

Disadvantages:
Big mess: By the time the jacket was installed, everything in the enginehouse (tools, workbenches, machine tools, roof supports, walls) was dusted with calcium silicate dust. If I did this again, I'd be tempted do the lagging outdoors in dry weather, or confine the dust to a temporary lumber-and-visqueen enclosure built indoors.

(C&NW 1385's new all-welded boiler

Storage: If the engine will be stored indoors, calcium silicate is great. Long-term outdoor storage will result in soggy calcium silicate trapped against the boiler, which accelerates corrosion. (Painting the boiler with high-temp primer and high-temp aluminum paint - make sure its good to at least 400 degrees F; most paints cook and crumble at boiler temp - is recommended in any case.)

- Doug Debs

Having grown up in the industrial insulation industry in the 60's and 70's and run a business in the NY-NJ area for 10 years after my ME degree, I think that I have the experience to answer the questions. Cal Sil is the best for stability for foot traffic. It is messy. I have sold carloads of Pabco Cal Sil and it is on many Foster Wheeler boilers. The next best alternative is higher density mineral wool like Eagle Pitcher made. Exotic insulation bade by JM, Carborundum and B&W is ceramic fibers. You DO NOT want to use this and or cut it with power tools. Those little fibers will kill you. This is very high temp and is not needed. What you want to avoid is fiberglass. I have little experience with what the mfgrs call 750 degree fiberglass. The glass melts at 1300 degrees while mineral wool is around 3000 degrees. Both are spun like cotton candy to make the fibers. Fiberglass and resin binder will burn but mineral wool will not. HD mineral wool would be my choice. Yes, it is itchy too. Cal Sil for the high traffic. The problem with Cal Sil are the joints and most will double layer it. Min wool does not have that problem.

We also spooled truckloads of tie wire and much of NYC construction used our National Standard Copperply wire as it was specified for the copper coating. Black wire will rust and galvanized is too hard to work. Best thing is stainless steel wire. We sold that to Con-Ed in place of Monel. SS wire that is 300 series is very easy to work with when it is 18 or 16 ga. 14 is a little stiff.

We also sold stud welders that were used to put small weldments onto vessels to tie the blocks in place. Capacitor discharge studs are great and do not leave any penetration or problem with annealing Same with pins and washers.

DO NOT use baling wire...

Then you have the sheet metal to consider... Make sure that the seams shed water. If you use Aluminum, the calcium silicate will eat it up. My dad invented the polyethylene paper backing that was laminated to the aluminum. He also invented the corrugated aluminum jacketing. Aluminum jacketing is for pipes...not boilers. But I mention the issue with Aluminum for obvious reasons.

Please explain why that is. Temperature isn't the issue in that the exterior of locomotive boilers are generally below 400° F (Excepting those rare engines with lagged smokeboxes.)

That may be what is in "adaptive reuse" here, scroll down to August 01, 2012: http://sp9010.ncry.org/cab2.htm

Roxul Insulation made by Rockwool. I'm not sure what it is made of, but it is not fiberglass so you won't get the itching. It is also highly fire resistant. https://www.rockwool.com/north-america/

It might be worthwhile to invest in a waterjet cutting rig if you're going to be shaping calcium-silicate or similar hard material. You definitely do if you're going to work with 'shuttle tile' ceramic fiber blocks.

I'm still playing around with a combination of multiple reflective shield and aerogel nanoinsulation for some of these applications. You could use spacing pins or blocks of shaped calcium silicate as 'standoffs' for the boiler clothing without much loss in overall insulation effectiveness.

Does anyone (Hugh Odom, for example) know or can find out in technical detail what was used for the various parts of rebuilt BR 52 #8055? That insulation was good enough that the locomotive would hold 300psi pressure in winter ambient temperature with water circulating through only about 35kW of water-heater-type heating elements...

Kaowool.

I know that the main change made to 8055’s insulation was to significantly increase its thickness. Here are a couple of photos of the boiler being insulated during its rebuild/modernization

https://www.eisenbahnfreunde-zollernbahn.de/loks/1bild806.htm

More photos of the rebuild are here: https://www.eisenbahnfreunde-zollernbahn.de/loks/1bild52n.htm

Much of the material looks like rock wool or equivalent but further back on the boiler the outer layer is a foil-backed material. I seem to recall this was a standard home insulation material. Roger Waller at DLM may be able to provide details.

IIRC, when I visited the Hagerstown roundhouse, back in the late '80s / early '90s, the crew working on 614? was using Kaowool. It sure seemed like an easier alternative to calcium silicate blocks.

Greetings:

When Tang Shan Locomotive & Rolling Stock Works built SY1647M for the Valley Railroad, we had specified that the locomotive was to be asbestos free. Our locomotive was insulated with Calcium Aluminate blankets.

A few years later, we used it on our No. 40 as well. It was available in different thicknesses and widths.

We found it to be easy to work with, effective and reusable.

Be well & stay safe,

J.David