Coal Issues

[PeterCraymer]

I stopped using Kingsford or any briquettes and just use wood soaked in lighter fluid to start the fire. The charcoal took too long to get hot enough. Once the wood is burning well from the initial load, I throw in a little more dry wood and some coal (bituminous) on top. Once the coal is going, then add more until there is a nice bed going. I can be at full pressure in under an hour if I push it. I usually aim for an hour just to not stress things too much. I like the larger nut sized pieces and have found that the fines will make a hard layer and block the air (if they don't go immediately out the stack!) and can kill the fire. initially I don't rake a whole lot, just stir it up a little to make sure all parts are burning. Then just add on top. I have been using a mix with anthracite, but I never add any of it until the fire is well established. It takes too long to light compared to the soft coal.

Hope this doesn't cloud any thoughts!

Peter

[Steam Engine Dan]

steve, I'm a member of NJLS too. if you have more questions, feel free to ask.

[Steve Goodbody]

Further thanks to Fred, Peter and Dan.

I'll give it another go with my existing coal (after proper sifting) and see what happens with a thinner fire and no dust.

Peter - my problem hasn't really been getting the fire going in the first place it's more been the matting of the coal when it's alight, however I'll try using just wood as you suggest in order to fully eliminate the charcoal briquettes as a potential problem.

Dan - thanks also for your kind offer.

Best regards
Steve

[timmy wheeler]

Steve, please post how the thinner fire and sifted coal work out. Thanks, Timmy

[johnpenn74]

Guys I am a little confused,... In reading this thread I am seeing a lot of methods of prep of coal. While I have soaked coal to do smithing work, I am suspect that any tractor, steam engine, steam boat ever did any prep of their coal before use... Or is this part of the process when shorting sizes from the mine's plant? Are we hitting limitations on our models that just don't scale down? FLue size, grate gap size etc...??


JP

[James Powell]

John,

Some thing's don't scale well- in full size, to light a coal fire, the descriptions I have (mostly Scotch Marine) are to start with a decent wood fire (up to about 16" by a full stove kind of fire), and then add coal around the outside of it, get the coal alight, then spread the lit coal on more coal in the furnace, and go from there- after the first fire is lit, you just steal shovels full of burning coal and add them to a thin/bare grate and repeat until all the furnaces are alight.

In models, the spreading around isn't required, or really possible. So, in order to provide the bed of coals to light the coal on, what has become fairly traditional is to use charcoal. The easiest way to get said charcoal to light is to saturate it in something more flammable. Then, put in box, light, put some artificial draft (extension chimney or suction fan), let the charcoal catch (to a "bed of coals"), then add coal on top of this.

It is mostly scale difference, even in 4"/ft I don't have enough firebox to muck around with needing to spread a coal fire around. I think that until you get up to several square feet, it's going to work out about the same. If I was making up a fire in a full sized traction engine, that's how I would do it, but using wood instead of charcoal. (both will work, but I dislike cutting wood up to fit it into the box, as it needs to be in my case, somewhat less than 2x3x6"- the door is too small for a 2x4)

James

[David Powell]

The last time I had really good steam coal was 1963. It burnt with a blue flame, gave lots of heat and left just a little ash. At the moment I have 9 dustbins full of various coal some from strange sources. I start the fires with charcoal soaked in kerosene or varsol, add dry charcoal , get about 20 lbs of steam and then move on to coal. For the Montreal event I used a mix of Welsh steam coal,about 40% alleged Pennsylvania anthracite, about 40% and the rest a mix of unknown smoky stuff. I tried the "Club" coal there and found it too smoky for my liking. I ran 10 hrs on Saturday, found a little clinker on clean out, but was never short of steam. I have several grates for most models, hard coal on its own works well with 50/50 bar and spacing, softer coals and mixes seem to burn better with a higher proportion of air spaces, ashes remaining on the grates seem to make more problems for me than the actual coal quality, unless it is really poor. Hope this helps David Powell

[sncf141r]

Some thing's don't scale well- in full size, to light a coal fire, the descriptions I have (mostly Scotch Marine) are to start with a decent wood fire (up to about 16" by a full stove kind of fire), and then add coal around the outside of it, get the coal alight, then spread the lit coal on more coal in the furnace, and go from there- after the first fire is lit, you just steal shovels full of burning coal and add them to a thin/bare grate and repeat until all the furnaces are alight.

Most of my large steam work has been oil, last time lighting a coal locomotive was 2004. (I let my TSSA certificate lapse last autumn, have not done any large steam in a few years now)

At that time in Utah, (2004), shovel coal in, throw wood on top (a couple of old pallets seem ok). You don't really need a lot of wood. Throw on top a kerosene soaked rag or three.

throw in fusee. (lit, of course)

You can climb underneath and actually see the fire spread through the coal. I found that really neat, and (pardon the pun) enlightening! John Rimmasch is a good teacher.

As you know, with a large locomotive, thermal stresses mean hours (4 plus) from cold is required. Some of the oil fired locomotives took too short a time, but it was always tough to scale back the fire to a small fire without it going out.

Fun stuff - from talking to your Dad, I understand Robin Hood is back together in Ontario? JohnS.

[David Powell]

Robin Hood is indeed back together and running, although some work has yet to be done. James brought the tender with him and I repaired the hand pump connections so we now have three means to feed water. Robin Hood will burn ALMOST anything and make steam on it. Incidentally, the grate has not been out of the firebox since we have owned the engine ( Approx 22 yrs) The builder told us that, though it was possible to remove it with the engine complete, it would be virtually impossible to replace it without lifting the boiler off the frames. Regards David Powell.

[Steve Goodbody]

Had another steam-up yesterday which was a partial but not total success. I sifted the coal, started with lump charcoal, used a more powerful/higher volume electric blower fan, and tried a thinner fire. I mixed the bituminous and anthracite 50/50.

The good:
1. The lump charcoal worked very well.
2. The sifted and mixed coal overcame the clumping problem
3. The upsized blower fan was a success
4. With sufficient airflow the fire drew well and the pressure built quickly

The less good:
1. I could not get pressure to build either with the engine's own internal blower or from the blast when on the run or idling out-of-gear. There was insufficient draft to draw the fire.
2. Pressure would build easily with the electric fan.
3. This situation did not change with either a thicker or thinner fire.

I know that this engine had a reputation as an excellent steamer in the UK when fired on Welsh steam coal (the problem in the UK was keeping the safety valves quiet) and so it seems likely that the trick now is to increase the draft to suit the local coal. On these engines the internal blower is piped into the blast pipe and hence the blast nozzle does both duties.

I know that I'm about to overlap with Fred's current Hunslet thread, but here's my plan. Please let me know if I'm missing something here.
1. Try a variety of smaller diameter blast nozzles in 1/64" increments.
2. Try each nozzle with/without a removable cross (David Powell's recent suggestion to Fred)
3. If the draft is still insufficient then try a new grate with wider bar spacing

In conclusion, given that I know this engine was a good steamer, and seeing that the fire draws very well and pressure builds quickly with the electric fan, then it seems to me that what is now needed is more airflow through the fire with this coal. I am assuming that sharpening the blast (increasing the jet velocity) by reducing the nozzle size is likely the way to go. Am I missing anything here?

Thanks to all for your help and advice so far,
Steve

[Fred_V]

Using the blast pipe as the blower seems to be an issue. You can use one or the other but not both. I would think a separate blower ring would be a better way to go. Running out of gear would not make much draft as there is no load on the engine so the blast will be soft.

[LVRR2095]

One subject I haven't seen mentioned yet is the need to approach thermal equilibrium.
When you are first steaming up.....just because you have reached operating pressure this does NOT mean you are ready to go! You must wait until the entire engine (traction or locomotive) is hot. If any part of your model is still relatively cool to the touch....that cool metal is robbing heat from your furnace. With my weenie little 3/4" scale locomotives after I get pressure up.....I take a break and eat a snack and talk with my friends nearby. If I don't wait until EVERYTHING is hot, including the drive wheels and main frame, as soon as I head out on the track steam pressure drops dramatically. Now if I let the little thing sit and cook for a while and wait until it is uniformly hot....then the heat loss is mostly what is being used to move the locomotive. If you don't wait you are losing heat to steam use AND to trying to heat all of the still cool metal. Take your time and enjoy the entire experience.....not just the running. While waiting....this is a good time to oil around and depending on what time it is...have some breakfast or lunch.
Keith