Backyard welded stove. Key issues with burning coal?

Hi,

I'm not in Pensylvania, but this seems like the best place i could find on the internet for coal stove questions.
I'm from UK, but living in Central Asia, where the winters are cold and the local power supply unreliable. (Energy rationing even in the capital last winter).
So i've bought a coal stove and installed it into our living room, which is right now quite toasty and pleasant. It's a fairly basic thing - cylinder with two doors, whole in the back to which i've attached a chimney going out a window (replaced one pane of glass with a piece of metal with appropriate sized hole). There are some metal bars welded - to make a grill. One door opens to the "fire box", the other below the grill to where the ash collects.


I'd like to improve the stove set up i've got if i can, and was hopeing someone would be able to help with some basic questions - or just checking i'm going in the right direction.

I'm guessing the most important thing i need to do is to get control over the airflow into the fire box. And am planning on putting some ceramic string around the door and around a hole which the stove has in the top.

Otherwise, i feel like the grate is too big, as there's a lot of small (garden pea size) burning pieces of coal which fall seem to fall through and into the ash. Any thoughts on what size the grill should be? I've experimented putting some quite fine wire mesh over the grill, but this seems to clog up with ash, reducing air flow.

There's a brown tar like thing which seems to be coming out of some gaps in the chimney. What could this be? is it a danger?

The coal i can get is probably quite bad quality, with all sorts of sized pieces together, between dust (about 5-10% of each bag) to pieces which are too big to fit in the door of the stove.
Is there an easy way to break bigger pieces?
A co-worker told me you can some how mix finer coal dust with water, and make balls out of it - so that it burns better. Anyone have any experience with that?

I've installed a CO monitor. Is there anything else i should be worrying about?

Is there anything useful to do with the ash (actually i'm sure i can find an answer to this on the forum, so don't worry about this one)

With the doors closed the fire will stay lit for 18 hours, which is helpful because it's a lot easier to just add some coal when i get back from work, rather than having to relight it every time.

I had hoped it would be a secondary cooking point (for those powercuts)- there's a hole in the top of the fire box, where you can see the saucepan in the picture. However - it seems that I was over optimistic, since the one time I tried it, the water in the saucepan was only warm, after several hours. I think it's too high from the coals to receive enough heat.

Thanks a lot in advance. Reading the posts elsewhere, I'm sure people will be friendly.

All the best,

Tom

So, Tajikistan really exists. You are really getting back to basics.

About the grate. The size of the slots are determined by the size of the coal being used, but in your case you don't have uniform sizes. Coal stoves usually have some means to shake the grate to clear the ash which your stove does not have which means you have to poke from above or below to clear that ash, or with large openings in the grate it does not get ash bound easily which it might do if smaller openings are used.

The lower the grade of coal the more organic material it might contain which in producing smoke might also produce creosote which is flammable and dangerous if allowed to accumulate too much.
Wood burners generally run a fire wide open and very hot for a period each day to help burn this up. Creosote, if that is what it is, smells bad. Coal that burns with smoke and yellow flame needs plenty of air over the fire through that upper door. The lower door should be capable of sealing air tight with means to adjust the air supply.

Sorry to have to speak in such generalities but without being there and seeing, that's the best I can do. Not every day I can write to a British Raj living in the lap of luxury.

TajikTom wrote:There's a brown tar like thing which seems to be coming out of some gaps in the chimney. What could this be? is it a danger?

Check the inside of the chimney pipe for excessive soot build up.
It seems like you are burning sub-bituminous or lignite which has a high moisture content and could explain the tar.
A member of this forum who lives in Alaska was burning sub-bituminous coal and experienced a chimney fire from what I think was caused by lots of soot in the chimney. While it's unclear if the soot alone caused it and this is the only chimney fire from coal soot I have ever heard of, it is something to keep in mind if you are using a lower grade of coal.

The grate (grill) bars should be no more than about .5 inches (1.5cm) apart and you will need to poke from above and below to get ashes to fall into the ash pit as Franco mentioned.

TajikTom wrote:With the doors closed the fire will stay lit for 18 hours

That is really a good burn time if you are indeed burning a sub-bituminous coal.

Is that piping behind the stove some kind of hot water heating?

Edit: The stove pipe goes into what looks like a tin/sheet metal box of some sort...could you explain what that is?

rockwood wrote:The stove pipe goes into what looks like a tin/sheet metal box of some sort...could you explain what that is?

I'm glad I wasn't the only one to notice that. I'm really hoping it's not being used to put hot air from the exhaust into the room. Good way to kill oneself.

It sorta looks like a home made heat exchanger. Is that what it is?

On a slightly different subject.... Welcome from half way around the globe! We're glad you stopped by and said "Hi". Congratulations on being inventive enough to find a way to stay warm. It's an age old purpose in life and you've done well to do what you have. Also, I'm pleased to see you have the sense and wherewithal to get a CO detector. We humans have been heating with coal for a long, long time, but only since the invention of the CO detector have we done it with good peace of mind.

Well... now that you have a friend or two on the other side of the big pond.... I'm curious to know two things: One: Is shipping of freight a trusted way to have items appear on your doorstep? And two: Do you have a monetary income that would allow you to save up and purchase a real coal stove? I'm guessing that you acquired the best you could, or the best available, but if it's was within your budget perhaps a new found friend in the USA would be willing to package and ship a better burning device to you. Maybe the shipping would be far too costly, perhaps making it impossible, but wouldn't it be fun to have a stove with cast iron shaker grates appear?

Tom

If you need some gasket rope and you are having a hard time locating some drop me a line and I can send you some. I ship packages overseas almost every day so one more in the pile isn't a big deal.

I know what it is like living overseas. Somethings the things we like or need just aren't available. Also WELCOME to this website. The people here are some of the best in the world!

Onedollar

Wow - what a great response, and really useful.

I've added a gasket rope - i brought some from UK while i was back for Christmas, and it's really made a difference having the top door properly sealed. Means we can now get a good roar going on the fire, and i can visibly see that the coal is a lot hotter - more white. plus the room is 5 degrees warmer or so. I've also now got more control effect from opening / closing the bottom door. It's amazing to see the difference that comes 5 minutes after opening or closing the bottom door.

My next but one task, is I think, to make some kind of movable panel, which can slide accross the bottom opening to give me better precision in how i control the air in flow.

The silver thing on top is a heat exchanger. Well done Vin maker. I work for an NGO which promotes them for the rual Tajik communities, as a way of reducing their consumption of wood. (The mountains here are slowly becoming deserts - which is why i thought it was a good idea to use coal - more respectful of local natural resource issues). Their designed with an internal compartment, which can be used as an oven, though mine has only reached low 100 degrees centigrade. (For farenheiters : a bit above water boiling temp)

Creosote sounds like it must be the issue with the brown liquid, though it could have rain / snow melt / general condensate mixed in to. It barely smells. So I'll have to find a way to check that. Could be a problem with the heat exchanger, as it has internal areas that i can't get easily, and which have platforms that it could easily build up on. This probably ought to be my first task I think.

thanks again for the advice - i wouldn't really say that I'm a british raj, in the lap of luxury. Though i'm a lot warmer this winter than previously. Tajikistan is very much former soviet / Russian space, albeit with a persian / iranian culture. The white pipes behind the stove in the picture are now defunct soviet built heating system, which hasn't been maintained - quite common in this country.

. I'm curious to know two things: One: Is shipping of freight a trusted way to have items appear on your doorstep? And two: Do you have a monetary income that would allow you to save up and purchase a real coal stove?

Using DHL or TNT will make things turn up on your door step from around the world, but is quite expensive (A letter is 40 usd) (5kg of documents is 400 USD) and although i have a job - it isn't enough to justify what would be 1000's to get a good stove out here. Airlines will ship things as far as the airport, which is good enough if you're willing to spend some time negotiating with customs officials, but I'm not sure whether I'd be staying long enough to justify it. (Diplomatic workers can sometimes be a bit more extravagant in that wayt, i hear that one embassy here, drives a few trucks out every 6 months, so their staff can move things back and forwards - but i don't currently have access to that kind of perk.

I doubt that brown liquid is creosote, if it has little smell it's likely just a water and soot mix that has leaked out of your flue. In fact, this is one of the reasons that your heat exchanger device will work better with coal; the cooling of flue gasses won't present the chimney fire/creosote danger that you will get with wood.

Tom, interesting place you live. Do you get to see views like this out there?

http://www.panoramio.com/m/photo/29616509

Could you post photos or give a detailed description of that heat exchanger/reclaimer? I'm interested to see how it's designed.

rockwood wrote:Could you post photos or give a detailed description of that heat exchanger/reclaimer? I'm interested to see how it's designed.

Here's some extra pictures of the heat exchanger.



I've actually put this one in place upside down. The pipe which was supposed to be on top, was longer than the one which was supposed to be on bottom (though i think, not for any particular reason). And i needed the longer one on bottom, to lift it away from the wooden window sill behind. The right way up, the point would have been at the top, and there would be an additional hotter flat space at the bottom of the inside cavity.

I've seen a few different models.
They all consist of a box or boxes into which the smoke passes,

I think it's galvanised steel. The edges are kind of folded over each other.


It released a lot of smoke into the room, so i've tried to seal the edges with some stove cement.

I think this design is considered more popular due to the box in the middle, which can be used for cooking. Mine is probably around 100 degrees, when the fires going well. I haven't measured it, but i know it's not really hot enough to cook, but quite a good place to keep food warm once it is cooked. I was told they were more intended for use with wood stoves where the fuel is burning quicker and get more draft. Whereas with a coal fire, they have less impact, as one aims to get a hot slow burn, which produces good heat, but prodcues less draft - so less exchange takes place.

Welcome to NEPA Crossroads Tom.

Your backyard welded coal stove seems to be working better than some of the factory made stoves members of this forum have reported using.
It sounds like you have a good handle on what needs to be done to get a good burn, and are making those modifications to your stove.

If you look under the "Board Index" for forums, you will see some forums of general interest, not just coal related topics. I, and I expect others here would be interested to hear more about your experiences in Tajikistan.

Welcome to the FORUM my friend. Nice looking, functional set up you've got there. Ya done good TT

TajikTom wrote:
There are some metal bars welded - to make a grill. One door opens to the "fire box", the other below the grill to where the ash collects.

You've put gasket material on those I see, so you've got that taken care of. What do you have for tools to work the fire with?

If you can add controlled air feeds both on the bottom and top door, that would be a great help. Don't know what you have there to work with. If you can get a welder to work with you, you can take either threaded rod or bolts and then a nut with a big washer and use it like a spinner. Weld the threaded rod to the door, cut holes next to it that the washer will cover and then you can open and close them by spinning the nut and washer open or closed... If you are using a bolt, drill a hole through the door and mount the head of the nut on the inside of the door so the washer and nut can close tightly on the outside of the door. You want a big washer, might have to make it from sheet metal. I'm talking 2 or 3 inches in diameter...

TajikTom wrote:Otherwise, i feel like the grate is too big, as there's a lot of small (garden pea size) burning pieces of coal which fall seem to fall through and into the ash. Any thoughts on what size the grill should be? I've experimented putting some quite fine wire mesh over the grill, but this seems to clog up with ash, reducing air flow.

In your set-up, you don't have the ability to shake the grates, your fuel size is quite variable, so this one you'll really have to play with. Without the ability to put in some kind of shaker grate system, upgrading these would simply be optimizing the spacing for the fuel you have to allow ash to fall down and keep burning fuel above... Only you can figure that one out...

TajikTom wrote: There's a brown tar like thing which seems to be coming out of some gaps in the chimney. What could this be? is it a danger?

Can you take some good photos of your fuel? Talk to us about how it breaks up, can you break it easily with your hands? Need a hammer? That kind of thing. Also, break some and take a photo of the surface that you have broken open.

TajikTom wrote: The coal i can get is probably quite bad quality, with all sorts of sized pieces together, between dust (about 5-10% of each bag) to pieces which are too big to fit in the door of the stove.
Is there an easy way to break bigger pieces?

Sledge hammer should work fine...

TajikTom wrote: A co-worker told me you can some how mix finer coal dust with water, and make balls out of it - so that it burns better. Anyone have any experience with that?

When in Rome do as the Romans.... Let us know if it works...

TajikTom wrote: I've installed a CO monitor. Is there anything else i should be worrying about?

TOTALLY AWESOME!

TajikTom wrote: Is there anything useful to do with the ash (actually i'm sure i can find an answer to this on the forum, so don't worry about this one)

We don't know what exactly your fuel is.. But, ash usually makes a good base for making paths or roadways. Anthracite ash is not good for the soil as wood ashes are. Again, don't actually know what you are burning...

TajikTom wrote: With the doors closed the fire will stay lit for 18 hours, which is helpful because it's a lot easier to just add some coal when i get back from work, rather than having to relight it every time.

And you're complaining???? That's darned good!

TajikTom wrote: I had hoped it would be a secondary cooking point (for those powercuts)- there's a hole in the top of the fire box, where you can see the saucepan in the picture. However - it seems that I was over optimistic, since the one time I tried it, the water in the saucepan was only warm, after several hours. I think it's too high from the coals to receive enough heat.

Well, the photo shows either a really large pot or a really small stove.... I've never had a lot of success cooking on stoves with this kind of geometry. They do work more like a crock pot, if that works for you.

If you look at cook stoves, you'll see that the main burners where you cook sit very close to the fire. Plus, they have removable plates so you can expose the cooking pot to the fire. You might do Ok if you have a stash of wood you can throw on top of your coal fire when you want to cook might work. I know, you are trying to not use it... But it may work a lot better for cooking than coal...

Good luck, and welcome to the forum..

dj