Author Topic: 3 inch boiler build  (Read 10012 times)

Offline Ye-Ole Steam Dude

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Re: 3 inch boiler build
« Reply #165 on: October 10, 2018, 10:06:38 AM »
Hello Gary,

Very impressive and a job well done.

Have a great day,
Thomas

Offline gary.a.ayres

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Re: 3 inch boiler build
« Reply #166 on: October 10, 2018, 12:25:16 PM »
Thank you all three   :)

@ MJM460 - lots of good information and advice there for me to consider. Am pleased that meths isn't considered second-rate - firing the boiler on it gave me a good feeling! Interesting point about that gap between burner and boiler - I think it warrants further exploration... though I'll probably aim to close it once the thing is properly assembled.
On the burner casing - yes, I have several modifications in mind for this - the way it is presently is just a start.
Good idea re a more controlled steam test. I had assumed that I'd need the pump connected up for that (which it will be, but isn't permanently connected yet), but I can see now that that isn't strictly necessary as long as the water level is kept an eye on.

@ Peter - will keep an eye on th flame colour. Indeed, the flame seemed clean enough, albeit yellow in colour. Very little soot was formed.

@ Thomas - cheers  :ThumbsUp:

Offline Kim

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Re: 3 inch boiler build
« Reply #167 on: October 10, 2018, 02:36:17 PM »
Very interesting test, Gary!
Thanks for sharing your experiment.
Kim

Offline gary.a.ayres

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Re: 3 inch boiler build
« Reply #168 on: October 10, 2018, 05:42:03 PM »
Cheers Kim, and thank you for your interest.

gary

 :ThumbsUp:

Offline MJM460

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Re: 3 inch boiler build
« Reply #169 on: October 11, 2018, 12:03:22 AM »
Hi Gary, the heating value of Meths is about 26000kJ/kg, only about half that of other hydrocarbon fuels such as propane and butane, so you have to burn more of it.  It is a less intense flame, you could never silver solder with it, but not too severe on a small copper boiler and not too hot means most unlikely to damage the boiler.  Probably not the answer for a passenger carrying 5 inch gauge loco, but more than adequate and very safe for running a small small engine.  Even those small gauge locomotives such as run by Zephryn and Paul, so well loaded for their size.  My engines are 12 mm bore with 12-16 mm stroke double acting and my small burners and boilers run them at up to 2000 rpm by my digital tacho, so more than adequate I feel.

A good source for a commercial burner is the Trangia stoves used by hikers.  (Not the ones sold as warmers for food dishes, which tend to be too gentle.). The whole outfit with cooking pans etc is expensive, but light weight for hikers, but the replacement burners are quite inexpensive at hike equipment shops.  Ideal for your vertical boiler.  Looking at the full kit will give you ideas for making the firebox, with air holes near the base below the flame, and how much height they allow between the top of the burner and the base of the cooking pan.  One fill of 30 -50 ml will raise steam and give 10-15 minutes run time if you insulate the boiler.  Obviously you will need to make something with a separate tank if you want to run for a lot longer and use your feed pump.  Otherwise, when the fuel runs out, top up the boiler with the pump, refil the burner, and you are soon away again.

MJM460
The more I learn, the more I find that I still have to learn!

Offline gary.a.ayres

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Re: 3 inch boiler build
« Reply #170 on: October 11, 2018, 06:44:01 AM »
Hi MJM.

The more I hear about meths, the more I like it!

Funnily enough I had toyed with the idea of adapting a camping stove. Is it something like this that you mean?

https://www.amazon.co.uk/Trangia-Spirit-Burner-with-Screwcap/dp/B000AR7970/ref=sr_1_1?s=camping-hiking&ie=UTF8&qid=1539235735&sr=1-1&refinements=p_4%3ATrangia

If so, what would be the advantage (if any) over a home made burner with a cap with say four wicks held in brass collars?

Thanks for your input.

gary

Offline MJM460

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Re: 3 inch boiler build
« Reply #171 on: October 11, 2018, 08:33:33 AM »
Hi Gary, yes, that's the one.  The advantage is that ring of little holes around the opening.  When the unit heats up, the Meths in the bottom starts vapourising, and the burn switches from gentle flame in the middle to little tongues of blue flame from each of those holes.  I suspect a bit hotter than a wick flame.

MJM460
The more I learn, the more I find that I still have to learn!

Offline gary.a.ayres

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Re: 3 inch boiler build
« Reply #172 on: October 11, 2018, 12:19:22 PM »
OK thanks - will bear it in mind.

Cheers,

gary

Offline gary.a.ayres

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Re: 3 inch boiler build
« Reply #173 on: October 16, 2018, 11:15:37 PM »
Well, not such a successful day today.

My tests of various firing methods continue. Today I tried wood - small pieces of bone dry hardwood in fact.

Because the boiler is small and only has five tubes, I reasoned that a large, tall, bell-shaped firebox would funnel the heat up into the boiler and compensate for any lack of draw. I rigged up a rough version of this out of a couple of iron and steel water pipe ends and connectors that I had scavenged from a skip some time ago.

I don't have an electric blower but I did use a small blowpipe to enliven the fire ('inspired by the 'boufadou' as used in France instead of bellows). I now also have a steam blower fitted to the boiler.

The arrangement was not a success. The tall firebox only served to hold the boiler too far above the heat. Lack of ventilation led to a situation in which the fire would blaze with the blowpipe on it but would dwindle as soon as I stopped puffing. The steam blower tugged valiantly at the fire but ultimately there was just not enough heat getting to the boiler.

This is not a major problem as the boiler has already performed heroically on both gas and meths. However, I would also like to be able to run it on wood, coal and charcoal if possible, so I will persist. This evening I began radical surgery on the firebox in an attempt to fix the above problems. The next firing will see the boiler sitting closer to what should be a hotter fire, and I may use charcoal for it.

That could be some time away, as I'm going away next week and when I come back I'll have to temporarily shift focus on to other projects from early November up to Christmas, as there are a couple of special presents I plan to make.

None of this seems to happen quickly...

gary

Offline Gas_mantle

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Re: 3 inch boiler build
« Reply #174 on: October 17, 2018, 12:03:21 AM »
Gary,

Could you try with softer 'splintery' wood that may burn easier? I think in relatively small quantities hard wood might be difficult to burn well enough.

Before I bought an electric blower I used my Hoover close to the chimney!  It works well but don't get too close with the hose as it sucks red hot embers into the Hoover body  - I'll leave you to figure out how I know that  :Doh:

Offline gary.a.ayres

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Re: 3 inch boiler build
« Reply #175 on: October 17, 2018, 06:31:56 AM »
Peter -

you may be right about the wood. Thanks for the tip. I'll continue to experiment with various forms of solid fuel but I think the firebox modifications are required anyway. The boiler looked good on the tall firebox - kind of Middle Eastern, a bit like some kind of sheesha pipe that you see guys smoking outside Lebanese cafes on Marylebone High Street - but it was just too far above the fire, so the top part of the firebox shell was in the lathe last night, getting sliced down to a less imposing size.

I'm not 'drawn' (no pun intended) to electric blowers, and if I find that I can't do without one for solid fuel, I'll probably just opt for meths.

I had a similar experience with our vacuum cleaner - I hoovered up a red hot ember from our woodburner. We still have the same vac, as my untidy-looking silicone repair on the plastic housing has held good for several years   :Mad:  :)

gary

Offline gary.a.ayres

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Re: 3 inch boiler build
« Reply #176 on: October 25, 2018, 11:57:31 PM »
I'm part way through altering the firebox to a design which I *hope* will make it more conducive to running on solid fuel.

However, I'm off to France tomorrow and also have some other projects I need to temporarily turn to and they may occupy me right up to Christmas so there will be little for me to say about the boiler in the interim. I'll pick it up again when I have dealt with the other things, and post some photos at that point.

Meanwhile, and entirely separately from all of the above, I just treated myself to these two little gems - Mamod SE1 and SE3:





Reasons?

1. Nostalgia - I had an SE1 when I was a kid.

2. It's going to be a while before I finish the boiler and build my first engine, so this will be an easy way for me to witness some engines running in the nearer future.

3. My first engine will be an oscillator, so the Mamods (although way smaller) will give me a first-hand 'feel' of the build and functioning of such engines.

4. They are little objects of desire.

 ;)

They will need some restoration work at some point - as though I don't have enough projects on my plate already!

Offline gary.a.ayres

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Re: 3 inch boiler build
« Reply #177 on: November 08, 2018, 10:47:39 PM »
...the heating value of Meths is about 26000kJ/kg, only about half that of other hydrocarbon fuels such as propane and butane, so you have to burn more of it.  It is a less intense flame, you could never silver solder with it, but not too severe on a small copper boiler and not too hot means most unlikely to damage the boiler. 
MJM460

When I was in France the week before last I found some of this in the supermarket - alcool a bruler ('alcohol to burn'):





It's 88.4% denatured ethyl alcohol - in other words, I think, methylated spirits.

It's clear and colourless and smells quite sweet rather than the more mineral smell of meths. It's billed as for use as a cleaner, degreaser, solvent and fuel for spirit lamps such as those in fondues. I tried it out on one of the mamods and it did the job but I haven't fired that one on meths yet so can't make a side by side comparison. I'll try it on my boiler at the end of the year when I have the 'pre-Christmas' projects out of the way. I'm guessing it will be pretty much the same as meths bearing in mind the active ingredient is the same.

The main thing is that at 1 euro 92 cents per litre it's a fraction of the cost of meths in the UK, so I bought four litres of it...

Offline MJM460

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Re: 3 inch boiler build
« Reply #178 on: November 08, 2018, 11:19:23 PM »
Hi Gary, that should be worth a try.  I would be interested to know what forms the rest of the composition.  Meths is usually about 95-96% ethanol, with the rest water.  (It is quite difficult to enrich it more than that by simple distillation).

But 88%?  I wonder if the rest is something more flammable than water, some sort of oil to make it smell better for food warming etc.  Worth a try in the Mamod burner to see how much steam it makes.  Also set a small quantity alight in a flat baking dish in a safe place and check that you can extinguish it with a glass of water as you can with Meths.  I suspect you will be able, as the water absorbs the Ethanol, cools and extinguishes it.  Water on an oil fire floats and spreads it which is why you don't normally use water on a liquid fuel fire.

I thought I had commented on those two sentimental items, but don't see my reply.  They are really great but look like they need some TLC.  A great find.  I have a similar little single cylinder one, with the engine mounted on top of the very similar boiler.  It was my brothers when we were much younger.  I like that two cylinder one, it seems to have a basic superheater even.  Should drive Meccano machines well.

MJM460


PS. - Hi Gary, sorry, I see you did try it on the Mamod engine.  If it runs as well as it does on Meths, they are clearly similar enough in heating value, another good find.

MJM460

« Last Edit: November 08, 2018, 11:25:41 PM by MJM460 »
The more I learn, the more I find that I still have to learn!

Offline gary.a.ayres

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Re: 3 inch boiler build
« Reply #179 on: November 09, 2018, 09:02:25 AM »
Hi MJM -

I thought you might be interested in this    :)

I have looked around online and most of the info on alcool a bruler seems to be on forums and I find the information to be quite mixed.

However, most people seem to be saying that it contains about 5 - 10 % methanol so presumably along with the 88% ethanol that would bring the water content down to between 2 and 7 %, which it seems would make it similar to meths.

It also appears (from what people say) to burn cleaner than meths does, and so is felt to be better for cooking.

I would tend to trust the French on things cooking-related - they don't take any nonsense when it comes to food !

It certainly ran the Mamod (the single cylindered one above, which is now under pre-Christmas restoration  :)), but I have not yet made a direct comparison with meths. When I do so I probably won't be very scientific about it, but it should be obvious if there's a big difference in performance between the two. I'll make a posting here when I have done so.

My guess is that it will behave pretty much like meths, but more cleanly. If I'm right, it will be the way to go for spirit firing my boiler in the future, especially as it's a quarter of the price (though I do love the purple colour of meths...  8))

Thanks for your input   :ThumbsUp: