Boiler making hearth

[KWILParticipant @kwil]

There is no doubt that the cheapest and easy to obtain solution is the Celcon type aerated builder’s blocks, Dry them first. If you do not trust this method, buy just one and leave your torch directed at it for a while, the cool side remains just that, cool.  Yes they eventuially crumble away where the torch has had the most effect, but at the prices charged!!.

 

The business of surrounding closely, various parts to save heat loss seems more academic then necessary, surround to keep the drafts aware and the insulating blocks will reflect back the heat that does go their way.  Try it.

[Tony MartyrParticipant @tonymartyr14488]

The experience of building my first (probably only) 3 1/2″ boiler was that the outer containment, mounted on a ‘workmate’ and made of MS plate lined with vermiculite bricks was the non-critical part.

Small parts such as pipe fittings were soldered within the heath just resting on the blocks.

Since getting sufficient heat into large work and not allowing it to ‘get away’ is the difficult task it is the primary insulation of the work-piece that is critical. For this I used the insulation blanket sold be Cupalloys and got through 4 of them as it was necessary to cut pieces off to stuff the firebox etc during construction. Failure to wrap the barrel and stuff the smoke-box end when silver soldering the firebox area was my first error which I soon corrected.

There is a photo on my album of the wrapping prior to finishing the end-plate.

Tony

[EastleighiteParticipant @eastleighite]

Why do you need a hearth, to you intend using parafine blowlamps for heat?.

[Stewart HartParticipant @stewarthart90345]

I knocked one up using an old work mate, and a scrap yard ally tray sheet abd an oven tray, with Thermalite block from B & Q baught 1/2 price as they were damages 50p each.

 

Stew

 

 

[CirclipParticipant @circlip]

Good to see you teaching the collonials how to make a boiler Stewart, only things to remember, correct clearences, good flux and clean metal for Silver Soldering.

 

  Regards  Ian.

[Author]

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