What to use for boiler lagging and cladding

[photopro]

I have been working on my 1.6" scale Mikado for more years than I want to remember, but I am finally at the stage where I'm ready to insulate and clad the boiler. There seem to be a few options, but I thought I would ask and see what others think or are currently doing before purchasing materials.

I used to have a 1.5" narrow gauge Shay and used Fiberfrax lagging and blued stovepipe on that to very good effect but this new boiler is obviously much bigger and I don't plan to use blued steel on it. The plans call for an aluminum wrapper but I'm thinking I might use 20 or 22 ga. sheet steel to make it a bit harder to ding the cladding. I understand that aluminum isn't going to corrode as easily, but I think painting both sides of the steel with primer and color coat will go a long way toward extending it's life. It certainly can't be worse than maintaining the blued steel.

The insulation for the boiler is a bit more troubling, especially if I want it to double as a kind of backing for the cladding. The cladding is supported by standoffs to give the appearance of a tapered boiler and the distance between the boiler and cladding vary from 1/8" to o.8 inches in places. I remember Chuck Hackett saying that he had used something that was actually troweled on and shaped, but it was full of asbestos and probably isn't available any more. I am also aware of Chuck's tests that showed that insulation wasn't very effective in this scale but my experience is that the insulation at least keeps the outer wrapper a bit cooler to the touch. So far the only sources I have come up with for insulation are McMaster Carr and Vintage Steam Products.

[FredR]

Hey Doug. Hope all is good.
When I had the Atlantic, I had used the sheet FiberFrax as well. When I was researching FiberFrax, I thought I ran across something they made that was about like what you are talking about. What about the stuff they use to line fire pans in oil burners?
Fred

I have been working on my 1.6" scale Mikado for more years than I want to remember, but I am finally at the stage where I'm ready to insulate and clad the boiler. There seem to be a few options, but I thought I would ask and see what others think or are currently doing before purchasing materials.

I used to have a 1.5" narrow gauge Shay and used Fiberfrax lagging and blued stovepipe on that to very good effect but this new boiler is obviously much bigger and I don't plan to use blued steel on it. The plans call for an aluminum wrapper but I'm thinking I might use 20 or 22 ga. sheet steel to make it a bit harder to ding the cladding. I understand that aluminum isn't going to corrode as easily, but I think painting both sides of the steel with primer and color coat will go a long way toward extending it's life. It certainly can't be worse than maintaining the blued steel.

The insulation for the boiler is a bit more troubling, especially if I want it to double as a kind of backing for the cladding. The cladding is supported by standoffs to give the appearance of a tapered boiler and the distance between the boiler and cladding vary from 1/8" to o.8 inches in places. I remember Chuck Hackett saying that he had used something that was actually troweled on and shaped, but it was full of asbestos and probably isn't available any more. I am also aware of Chuck's tests that showed that insulation wasn't very effective in this scale but my experience is that the insulation at least keeps the outer wrapper a bit cooler to the touch. So far the only sources I have come up with for insulation are McMaster Carr and Vintage Steam Products.

[cbrew]

I am using 20 gauge steel on my American, the jacket is now 10 years old,
I did not lag the boiler as i did not like the idea of it not allowing water to freely run off and dry form the heat of the boiler or air.
I do have an air gap between the boiler shell and the jacket and it does not get so hot that burns you. yes it is hot but i can touch it with out damaging my skin.
20 gauge steel works well, I did not paint the inside. and i don't have a rust problem after ten years.
this could be because of the air gap.
I hope that helps

BTW i have heard of some using cotton sheets and plaster of Paris to lag the . tho im not sure how well that works

[platypus20]

While I don't make scale locomotive engines, I do work in the industrial boiler industry, there are a few products available to use for your project. Aside from Kaowool ceramic blanket, and rigidizer , which allows you to make you own wet pack, which is formable and retains its shape when it dries out, there are also some bagged industrial pipe insulation, like Smooth-Coat, that is pipe lagging without the asbestos. A 50# bag is about $60, and is available from any industrial insulation company. Its a powder, you mix up like oatmeal with water, the form on the side of the boiler, wood stove or scale engine. It can be trowel into any shape you need.

[cbrew]

While I don't make scale locomotive engines, I do work in the industrial boiler industry, there are a few products available to use for your project. Aside from Kaowool ceramic blanket, and rigidizer , which allows you to make you own wet pack, which is formable and retains its shape when it dries out, there are also some bagged industrial pipe insulation, like Smooth-Coat, that is pipe lagging without the asbestos. A 50# bag is about $60, and is available from any industrial insulation company. Its a powder, you mix up like oatmeal with water, the form on the side of the boiler, wood stove or scale engine. It can be trowel into any shape you need.

Hi jack, do you have a source?
Thanks

[platypus20]

I would look in the yellow pages for industrial insulation contractors/suppliers, if there is a local Johnstone supply, they might be be to help. Any industrial boiler company, like Cole Industrial (Lynnwood, Wa 425-774-6620) should be able to direct you to a source.

[kvom]

I was visiting RichD yesterday and the topic came up. He's using some sheet cork for one engine.

[765nkp]

On my son's mikado I used 16 ga sheet metal, so you can drill and tap it for the hand rails and stuff. I didn't use any insulation either, rather let the water run off any keep it dry. Insulation won't make any difference on a boiler like this.
A air gap works just fine.


Tim

[Fender]

Has anyone tried a radiant-type insulation? From the way I understand it, wrapping the boiler (underneath the jacket) with aluminum foil (a low-emissivity surface) would reduce the amount of infrared radiation from the boiler to the jacket, and reduce the heat loss.

[RichD]

My Atlantic is wrapped with 10 layers of a product (no longer available) called
"Non Asbestos" hi temp paper duct joint tape and a 20ga steel jacket. Works well.
Good support and the 20 ga is heavy enough allow attaching detail diectly to the jacket.
On my Tenwheeler and Wren NG I will be using over the zinc phosphate primered and hi temp
manifold painted boiler, a single layer of ceramic paper and then a layer of 1/8" cork.
The cork will slightly char at 125 psi temps (actual test case), so the ceramic paper will
protect it. Not much insulation value for sure, but I want support for the jacket.
A layer of aluminum foil, shiny side in, against the boiler will help as well.
For jacket material use pre prep (primered) steel sheet if you can find it.
RichD

[Pat Fahey]

HI

On my 3/4" scale boilers , I was using felt fabric , the cheapest that I could find , for insulation , it was easy to work with , and cut to fit around the boiler , As for the boiler jacket , yes it was stovepipe , that was primed and painted . Pat WLS

[FriscoJim]

I've used header blankets with good results:
http://www.thermotec.com/products/14003 ... anket.html

They are flexible, thin, easy to cut, readily available and will take the relatively low temps of a typical boiler (as compared to an exhaust header). The only downside is that I expect a thicker Kaowool or Fiberfrax insulation would be a more effective insulator... just depends on how thick you want your insulation. Just another option to consider.