What size boiler is recomended for a S50 steam engine?

[Maxjon]

This one could be big enough to modify...

 

[Maxjon]

The D320 Boiler is 70mm high, x 80mm diameter....maybe too small to add a coal firebox/cylinder below it....
/

 

[Steamchick]

The difference us simple. A WilesCo or Mamod is a small kettle, relying on easy combust ability of fuel so it gets enough draught. Not good for coal. Coal needs a tall chimney for good draught to get enough air to burn. Or forced draught as with the loco type boiler using exhaust steam through a venturi funnel to develop the draught. But your engine will use so little steam, it won't be that effective. My Dad made a boiler 3 in Diameter, horizontal, with closed fire box, a tall chimney and exhaust steam forced draught. His Paraffin blowlamp didn't function well until he used a small compressor instead of exhaust steam to develop adequate draught. Coal needs more than even that draught.
But a small traction engine using more steam in the engine manages a coal fire in the firebox about 2 in x 2 in x 3 in high, then through flues to the smoke box with an exhaust steam blower... - because it develops more exhaust steam than small stationary engines in order to power the tractor along. Prtly because it runs around 80psi, not 15psi. (More than 5 times to puff!).
So, "been there and done it".
I suggest gas fired is the best option for your first boiler and engine, then build a bigger engine with boiler for coal firing, when you have developed steam running expertise using gas.
To train new guys at the local club, we have a couple of gas fired boilers - with old engines, that we loan to "Newbies" - and after a lesson or 2 in "What to do", and a supervised session, they can run them at shows for demo to the public. Usually they enjoy a couple of happy hours fiddling and tweaking and learning the foibles of steam demand by the engine versus gas supply to the burner, and how often to feed water, and the consequences of how that drops pressure a bit and you need more gas to keep the engine running while restoring pressure.... etc. They then take charge of the boiler and engine and get involved stripping and re-building anything needing on the set-up... All without making their first engine, or experiencing a loco, and coal firing.
One guy has since taken on a 5in gauge loco and is learning to run it around the track.... After 4 hours of track time, he still struggles to maintain fire versus steam demand versus watering... but is improving at each session. He has also learned to service the loco, as well as keep it clean, oiled, and in good condition.
Another guy has learned about engines by restoring a small traction engine, that is not yet restored to coal firing, but now runs on air as a demo in shows, after a strip and re-painting last winter. Next winter maybe the boiler will come off and be serviced for steaming next year?
It is good to learn from some simpler basic tasks before thinking of a full coal fired set-up.
K2

 

[Jasonb]

Even a small traction engine with that size grate such as a Minnie is a pain to keep the fire going, those that do run them get better results with the kerro soaked charcoal as I mentioned earlier.

If you are relying on the blast nozzle (exhaust steam) to give you enough draft to keep the fire going what do you do if you stop or slow the engine as the steam will not be constant. lets face it we all like to see an engine ticking over slowly not reving it's nuts off. You could use a blower but that draws more steam from a small boiler that will be trying hard to make enough

Boilers like that wilesco spare part will not be designed for solid fuel, there will be no radiant heat into wet legs and not much in the way of flue tubes.

 

[Steamchick]

Jason, we agree. Thanks for saying the same in a lot fewer words than I use.
K2.

 

[Maxjon]

The difference us simple. A WilesCo or Mamod is a small kettle, relying on easy combust ability of fuel so it gets enough draught. Not good for coal. Coal needs a tall chimney for good draught to get enough air to burn. Or forced draught as with the loco type boiler using exhaust steam through a venturi funnel to develop the draught. But your engine will use so little steam, it won't be that effective. My Dad made a boiler 3 in Diameter, horizontal, with closed fire box, a tall chimney and exhaust steam forced draught. His Paraffin blowlamp didn't function well until he used a small compressor instead of exhaust steam to develop adequate draught. Coal needs more than even that draught.
But a small traction engine using more steam in the engine manages a coal fire in the firebox about 2 in x 2 in x 3 in high, then through flues to the smoke box with an exhaust steam blower... - because it develops more exhaust steam than small stationary engines in order to power the tractor along. Prtly because it runs around 80psi, not 15psi. (More than 5 times to puff!).
So, "been there and done it".
I suggest gas fired is the best option for your first boiler and engine, then build a bigger engine with boiler for coal firing, when you have developed steam running expertise using gas.
To train new guys at the local club, we have a couple of gas fired boilers - with old engines, that we loan to "Newbies" - and after a lesson or 2 in "What to do", and a supervised session, they can run them at shows for demo to the public. Usually they enjoy a couple of happy hours fiddling and tweaking and learning the foibles of steam demand by the engine versus gas supply to the burner, and how often to feed water, and the consequences of how that drops pressure a bit and you need more gas to keep the engine running while restoring pressure.... etc. They then take charge of the boiler and engine and get involved stripping and re-building anything needing on the set-up... All without making their first engine, or experiencing a loco, and coal firing.
One guy has since taken on a 5in gauge loco and is learning to run it around the track.... After 4 hours of track time, he still struggles to maintain fire versus steam demand versus watering... but is improving at each session. He has also learned to service the loco, as well as keep it clean, oiled, and in good condition.
Another guy has learned about engines by restoring a small traction engine, that is not yet restored to coal firing, but now runs on air as a demo in shows, after a strip and re-painting last winter. Next winter maybe the boiler will come off and be serviced for steaming next year?
It is good to learn from some simpler basic tasks before thinking of a full coal fired set-up.
K2

Thanks for the sound advice K2! I look fwd to your knowledgeable replies!

 

[Steamchick]

Just trying to help you make your right decision. I am sometimes wrong as well, so check advice from others too.
K2

 

[Maxjon]

Just trying to help you make your right decision. I am sometimes wrong as well, so check advice from others too.
K2

I think most all the burner type Wilesco work on 20 psi, which you think should run the S50...Might work out economical to buy a Wilesco engine, to learn with, and ultimately use the boiler for the S50......

 

[Steamchick]

From engines I own, the S 50 is a similar size, perhaps a bit smaller, and we psi will drive it far too fast without a dynamo to use the power. I use around 5 psi to idle my engines. Steam volume is the problem for these tiny kettle boilers, not pressure. Enough flame will be OK,, but needs continuous water feed.
K2

 

[Maxjon]

From engines I own, the S 50 is a similar size, perhaps a bit smaller, and we psi will drive it far too fast without a dynamo to use the power. I use around 5 psi to idle my engines. Steam volume is the problem for these tiny kettle boilers, not pressure. Enough flame will be OK,, but needs continuous water feed.
K2

I was thinking the small kettle type will need a resivoir and pump. I'm keen to get the PM Research pump casting kit...

 

[Steamchick]

So simple I make hand pu,p's from bar stock.

 

[Maxjon]

So simple I make hand pu,p's from bar stock.

Nice I have plenty of barstock.....

 

[Steamchick]

Update on the little Mamod boiler project. This is just a little "fiddle" project to see what it can actually power... based on water heating ability and the small burner. (Maybe I should have just used a complete Mamod boiler?).
I have just bought a pressure gauge suitable range (from a coffee machine): another £20.
Air tested with a small compressor, of the size I use to run small steam engines similar to the S50:
The Safety Relief valve took a bit of tweaking to work reliably, but is now set FOR AIR at 1.1bar (16psi) = the right pressure according to the Mamod information I have gleaned... It will need re-setting for STEAM as the steam flow through relief valves changes their performance when in operation. By adjusting the top nut on the pressure relief valve I can change the relief pressure by as little as 1psi. And it manages all the air the compressor can give... I wonder how that compares to the amount of steam the burner will develop? - Watch this space!
K2

 

[Maxjon]

Update on the little Mamod boiler project. This is just a little "fiddle" project to see what it can actually power... based on water heating ability and the small burner. (Maybe I should have just used a complete Mamod boiler?).
I have just bought a pressure gauge suitable range (from a coffee machine): another £20.
Air tested with a small compressor, of the size I use to run small steam engines similar to the S50:
The Safety Relief valve took a bit of tweaking to work reliably, but is now set FOR AIR at 1.1bar (16psi) = the right pressure according to the Mamod information I have gleaned... It will need re-setting for STEAM as the steam flow through relief valves changes their performance when in operation. By adjusting the top nut on the pressure relief valve I can change the relief pressure by as little as 1psi. And it manages all the air the compressor can give... I wonder how that compares to the amount of steam the burner will develop? - Watch this space!
K2
View attachment 159565

Any further progress with this project?

 

[Maxjon]

 

[Maxjon]

I bought this to play with...not sure if I will restore it, or simply use it as a boiler....

 

[Jens Eirik Skogstad]

What pressure of steam would an S50 run to its capacity? 25psi?

Not only pressure, how much can the boiler produce the amount of steam per minute.

Too small boiler with correct pressure can't run the large steam engine due not enough steam run the steam engine due not enough amount of the steam to be produced per minute. Note: Large surface of heat = produce more steam per minute.

 

[Raygers]

Some drawings attached.
This will produce far more steam than you need, but similar boilers at 3 in diameter wil suit you. However, your ngine needs so little steam compared to that available from coal fired boilers, the boiler will be 10 times bigger than you need, and hard to manage as there won't be enough exhaust steam to keep the fire going.
Which is why people use gas for little model engines. - And coal for 5 in gauge locos on a railway hauling people.
K2

That's very similar to the boiler I am building at the moment. The drawings attached look very much like a Bolton Boiler, I have plans for a 6". With the price of copper and the fact I have to source it all from overseas, I'm in Canada, it's putting me in the poorhouse.
Why is there no build thread? Because I always forget to take my phone/camera out to my workshop, I get out there and get so involved I lose track of time. I have some photo's that I can rustle up and start a thread going.
By the way, this is my first boiler, my motto is "either go big or go home" So far it's been quite the trip.

 

[RobConway]

I am in Australia as well so purchased the MSN boiler as I wanted to display my model. (which BTW I have never done under steam anyway!) I purchased the Australian standards for boiler design which are great BUT, still needs someone to signoff the Boiler if used in public and noone wants to do that. A part of the MSN cost is their international insurances they need to maintain and what I needed to display a running steam model in public. I have to get back to my S50 as although it run, I think some more fine tuning was needed as didnt run easily when using compressed air as I thought it should of.

Maybe DM me as I am keen on understanding shipping costs now from the UK, I did my S50 some years ago now and can remember it was expensive. Was thinking of buying a D10 and put it away for retirement one day