Firing with Coal and Ash Pan question

[barts]

Regular angle will work fine; find some w/ a thicker section (3/16 or 1/4) and it will last longer. Having the open face up means it fills w/ ash; the air coming up from underneath will help keep most of it below 750 F or so, the point at which mild steel starts to have a finite life.

- Bart

[steamboatjack]

Folks,

Going back to the original questions on the first post, you will find that the majority of UK steam boaters using coal, use a “wet” ash pan, starting with about an inch of water in it, the engine drains etc. are all led into it and keep it wet despite the vaporizing effect of the fire. I lot of us also use instant BBQ bags to start, a bit expensive but quick & easy especially at a meeting. We also now have a source of good Welsh steam coal which makes a terrific difference.

Regards
Jack

[dhic001]

Using a wet ashpan might seem like a good idea, but some of us go to sea, where such a creation would result in a very messy engine room and burnt boiler beds because we were relying on liquid to stay where we want it, which doesn't happen at sea.

On both Zeltic and Kapanui (and every other steamer I've run) I always run with minimal amounts of ash in the ashpit, as a build up of ash can easily restrict draft through the grate, risking overheating the grate. The heat in the ashpit isn't a problem because there is sufficent insulation either in the ashpit or directly under it, which means heat transfer downwards is minimised. Certainly there was no sign of heat damage under the boiler when it was removed from Zeltic, after 10 years plus service, much of it in conditions most UK boats would stay home in.

Daniel

Folks,
Going back to the original questions on the first post, you will find that the majority of UK steam boaters using coal, use a “wet” ash pan, starting with about an inch of water in it, the engine drains etc. are all led into it and keep it wet despite the vaporizing effect of the fire.
Regards
Jack

[JonRiley56]

Thanks for the comment Daniel,

What are you using for insulation under the boiler. Right now I dont have anything. I have the boiler suspended 1" above the floor and that is not enough to keep things from being charred. I woulod prefer not to go much higher because I want to keep the center of gravity as low as possible. I do have the option of actually cutting a section of the flooring out, leaving the area under the boiler open to the bilge. Is that they way to go ? The closest thing to the underside of the boiler then would be the crossmembers that support the floor. They would be about 2" below the boiler. I could put a strip of aluminum or stainless on them to reflect some of the radiant heat.

Let me know your thoughts.

jon

[fredrosse]

From previous posts, a wet pan UNDER the ashpan will protect the boat, plus perhaps a few layers of ordinary aluminum foil between the ashpan and the wet pan to insulate the hot ashpan from the wet pan. The wet pan can have some terry toweling to keep the water from sloshing around. Stainless foil is better, but way more expensive, aluminum foil will work well enough. I think most important that you make the gaps in your firebars about 1/2 inch, rather than the 3 inches you have now.

[JonRiley56]

All,

I just had a thought, and figured I would share it before it died of loneliness. Is it possible that the issue i had with an excessive amount of heat under my boiler is directly related to my grate problem ? If all of my coals were falling through the grate (because of my 3" spacing) and forming a pile of glowing coals on the floor of the firebox, maybe it was getting a lot hotter than it typically would if it was mainly just ash on the floor.

Thoughts ? Maybe i am trying to engineer my way around a problem that will be addessed by having a tighter grate.

jon

[S. Weaver]

Jon:

You would still have radiant heat, enough to cause mischief with exposed wood or composite construction. As Fred, Jack and others are saying, some insulation medium is required.

[Mike Rometer]

Undoubtedly there will be less heat below if there is no fire in the ashpan, the radient heat will to some extent be counteracted by the updraft into the fire-box not being pre-heated on it way past the ashpan.

[JonRiley56]

If I put a layer of fire brick under the boiler would it seerve to protect the wooden deck ?

jon

[dhic001]

Sorry for the delay in replying. The bottom of Zeltic's ashpan has 1 inch of castable refractory on it. Below the steel is a thin stainless plate, then a layer of Kaowoll (1inch). this is held up off the bilge by another stainless pan. The bottom of the firebox would be about 1.5 inches off the timber at the nearest point.

Dealing with the grate will help greatly, both in heat transfer downwards, and in lifespan of the actual grate.

Daniel