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Vertical Boiler Fittings

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Neil Wyatt07/10/2018 21:04:24
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I'll echo that sentiment, well done Gary.

Neil

gary.a.ayres07/10/2018 21:13:02
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Julian and Neil - thank you both!

It was sometimes fun, and sometimes stressful, but experiencing those blasts of steam has made me very happy.

Thank you both for the advice you gave me along the way...

smiley

Edited By gary.a.ayres on 07/10/2018 21:14:00

Paul Kemp07/10/2018 23:51:20
147 forum posts
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Gary,

Well done that man! Doesn't it feel good when it all works? It's great to see new people coming along who are not afraid to put their own ideas into things and have the perseverance to make them work. Super job and an excellent video as well.

Couple of observations; very briefly priming is where water is entrained with the steam exiting the boiler, that can either be through the main steam valve to the engine or through the safety valve when it lifts (or both!). If the former it's very bad for the engine as it can lead to a hydraulic lock between cylinder end covers and piston, causing some spectacular damage in extremis. If the latter you know about it as it appears to be raining and can also be bad as it can reduce the level of water in the boiler very quickly as 'solid' water is being expelled through the safety. The main cause is as you say, impurities or high dissolved solids in the boiler water but it can also be caused be a high steam demand. There are some interesting videos on YouTube if you want to learn more about it.

At the end of operation it's good practice to let the pressure drop slowly as the boiler cools and not release the pressure quickly while the boiler is still hot. Not so critical with a copper boiler as a steel one.

Look forward to your firing experiments and ultimately seeing an engine on the end of the pipe.

Paul.

geoff walker 108/10/2018 09:11:58
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Yes, nice work Gary, I've followed this thread from the beginning.

Well done but like others I would love to see an engine running.

I have everything I need to make a boiler except the inclination.

Having seen your success I really must get on with it!!!

Geoff

gary.a.ayres08/10/2018 10:26:55
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@ Paul -

Many thanks for your kind comments. The basic design is from Stan Bray, but I scaled it up to x1.5 and there were areas on the original plans which were unclear so a bit of creativity (and consultation) was necessary. Yes, it does feel good, especially after all the trials and tribulations!

Maybe it isn't priming that can be seen in the video... I have seen one of Keith Appleton's videos in which he shows a boiler priming, and I thought it looked kind of similar. I'll look into it a bit more...

On the quick release of pressure - yes, I did wonder afterwards if I should have done that! Next time I'll release it more slowly, but now I'm glad I did it this way just the once (assuming the boiler wasn't damaged by it) as I'll be able to watch that spectacular whoosh of steam on the video whenever I like. 

 

@ Geoff -

Yes, I have noticed that many more people build engines than boilers. I can certainly understand that - I found this process quite stressful, worrying about leaks and so on. Also, the heat required for silver soldering it all together is not pleasant to work with. However, it's satisfying when it's done and there's something alchemical about the transformation of water into all that powerful steam. I encourage you to go for it.

I haven't built any engines yet - that's next up after I get the firebox for the boiler sorted out. The only reason I started with the boiler is that I hated the thought of building an engine and not being able to run it on steam!

 

Edited By gary.a.ayres on 08/10/2018 10:27:27

Edited By gary.a.ayres on 08/10/2018 10:28:14

Edited By gary.a.ayres on 08/10/2018 10:29:07

gary.a.ayres10/10/2018 00:12:03
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I did a test firing on methylated spirits this morning. It seemed to go quite well:

gary.a.ayres16/10/2018 23:23:51
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Not so good today.

I tried firing the boiler on small pieces of dry hardwood, but it didn't burn well. I'm pretty sure this was down to the firebox design (different from that seen in the video above) given the small size of the boiler and the fact that it only has five tubes. The boiler just didn't get hot enough. I'd like to be able to use solid fuel so I will persist, and I have already begun with some radical modifications to the firebox which I think should help.

Not the end of the world if I can't sort this, as it runs fine on meths, but I'll carry on for now and see how it goes...

Paul Kemp17/10/2018 00:58:12
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Gary,

Were you relying on natural draught for your hardwood fire? If so in such a small boiler you are unlikely to succeed. With small solid fuelled boilers it is the norm to have to provide draught by an external means to get sufficient steam to operate a steam blower. Steam blower is a tapping off the boiler and a valve piped to a small nozzle in the uptake (chimney) this induces air for through the fire. The external means used to get it going in the first place range from an electric fan placed on the chimney to draw the fire, a jet similar to the steam blower fed with compressed air either installed in the chimney or in a false chimney that drops on. Larger boilers like my 4" scale traction engine can use natural draught with the use of an extended chimney but my 2" scale engine will not respond to this and has to have an electric 'blower' (really a sucker) on the chimney until the steam blower can take over when I have about 20psi. The design of the grate with regard to air gap / fire bar ratio will also have a significant effect. Don't give up!

Paul.

gary.a.ayres17/10/2018 06:41:57
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Paul -

thanks for this. I'm aware of the issues you have outlined.

I didn't use an electric blower. What I did use was a small mouth-blown blowpipe (like the 'boufadou' which is used for the household fire in Southern France) which flared up the fire when I was using it but it didn't last and the fire soon went down again. I just thought I'd try it to see if it worked.

I have in fact now installed a steam blower which showed some signs of working and it did pull the fire but the whole thing just didn't get hot enough. I am reluctant to go down the electric blower route but I can see that one might make all the difference.

Once I have modified the firebox (and a better grate is part of my plan) I'll try again but I can see that I may have to decide between getting an electric blower or just using meths, which I already know works well. That said, with a better-designed firebox, the right choice of fuel and a bit of perseverance I may be able to coax enough heat into the fire using the blowpipe to get the steam blower to kick in. We shall see...

Cheers,

gary

Edited By gary.a.ayres on 17/10/2018 06:42:25

Edited By gary.a.ayres on 17/10/2018 06:46:05

Edited By gary.a.ayres on 17/10/2018 06:47:18

JasonB17/10/2018 07:13:17
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Try some lump charcoal (not brickettes) start with some that has been soaked in paraffin then when the fire is burning well use dry.

Small air line directed up the chimney will act as a blower before you can make steam to use the boilers own one and an extension to the chimney often helps.

gary.a.ayres17/10/2018 08:06:31
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Thanks Jason -

Yes. Amazingly, I still have some lumpwood charcoal left over after a Summer of endless barbecues, which should fit the bill nicely with paraffin to start as you say.

Will think about your air line suggestion, and how I might adapt it to my own peculiar ways. You have given me an idea...

Cheers yes

gary.a.ayres26/10/2018 00:04:17
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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 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:

 
 
 
 
They will need some restoration work at some point - as though I don't have enough projects on my plate already!
 
gary.a.ayres08/11/2018 22:56:29
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When I was in France the week before last I found some of this in the supermarket - alcool a bruler (alcohol for burning):

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' 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...

gary.a.ayres11/12/2018 00:32:43
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So...

Back on the boiler. Or I should say the firebox as the boiler itself is pretty much finished.

The test firings on gas and methylated spirits went well and raised a good head of steam. However, not so the solid fuel test using small pieces of hardwood in a roughed-out firebox, which failed to produce enough heat. Not to be deterred (not yet, at least), I'm now in the process of modifying the firebox to make it smaller and more compact to keep the heat near the base of the boiler, where it should be. Again, I'll start with a rough trial version in case it doesn't work. No point in wasting time!

However, in such a scenario the top plate of the firebox could be repurposed for use on a meths burner so there's no reason not to make a proper job of that from the outset. That's what I'm doing - or trying to do - now.

First, I cut a small piece off an empty oxygen cylinder from a portable oxy-mapp kit to form a short spigot (it can be seen in rough form in the first picture below). This will be brazed on to the firebox top plate and will fit up inside the bottom collar of the boiler as the conduit of heat from the firebox. A strip of carbon gasket material wrapped around the spigot will form a cushion and seal between it and the boiler.

The top plate is made of 5mm mild steel plate. I used a hole saw to make the initial hole for the spigot then proceeded to bore it to size with a boring head. I plugged the boring head into my new Sieg SX2.7L mill using a 2MT to R8 adaptor, only to realise that the thread on the drawbar of the machine didn't fit the arbour of the boring head. It was Sunday night, and I had neither the wherewithal nor the inclination to make a new drawbar. Rather optimistically, I gave the setup a go anyway. It worked at first, but as the hole enlarged and the radius of the boring head extended, the lateral forces generated pulled the boring head out of the quill. Not good.

Fortunately, my customized 'drill press milling attachment' (with a drawbar which fits the boring head) saved the day:

This contraption has raised an eyebrow or two in its time, but it has on more than one occasion got me out of a pinch and is actually quite good, especially as the drill press which powers it now has a three phase motor. And there are occasions when a bit of belt slippage is no bad thing...

For details of its workings, see this video:

With the central hole bored to size, I roughly sliced off some of the steel plate with my Evolution Rage mitre saw (wouldn't be without it) to make it manageable, and then back to the Sieg SX2.7L to cut the top plate to just over external diameter using a rotary table and small endmill. I'm finding I really like this mill - for a smallish machine it fairly hogs the metal:

Cheers,

gary

gary.a.ayres11/12/2018 22:35:07
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The firebox top plate and spigot are now done and are ready to be brazed together and fixed to the main firebox body with M4 screws:

Edited By gary.a.ayres on 11/12/2018 22:35:44

gary.a.ayres18/12/2018 23:32:53
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I spotted through the holes in the top plate then drilled and tapped (M4) the bolt circle in the top half of the firebox body:

I then took the firebox top plate off again and silver soldered the spigot for the bottom of the boiler on to it. Believe it or not my Sievert torch started playing up (again) during this operation and would not heat enough to melt the silver solder (which was cut into small pieces laid around the join), so I put the assembly into the woodburner in our living room - which had the assembly red hot and the silver solder flashing round the joint in no time. Dubious practice, but I got away with it! The join isn't the best, but it's actually better than it looks in this photo:

And here's where it's at currently - the bottom half of the firebox needs to be fixed back on, a few more tweaks made and it will be ready for another try with solid fuel:

And if I just can't persuade this little boiler to run on solid fuel, none of this work will be wasted as the firebox will easily convert into a meths burner housing.

Bazyle19/12/2018 00:35:52
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Softwood burns hotter than hardwood. BBQ cooks get a bit snooty about hardwood charcoal but its only advantage is that it has more structural strength stopping it turning to dust thus keeping space for good airflow. You want wood for starting the fire but charcoal just doesn't have the heat output of coal. You want pea to marble sized bits of a good steam coal, (not anthracite). I can barely run my loco on a poor coal but with good stuff that can look identical it goes like the clappers.

gary.a.ayres19/12/2018 06:55:45
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Thank you for this, Bazyle.

I was planning on trying charcoal first, but in response to your advice will speak to my friend about some steam coal.

Paul Kemp20/12/2018 10:05:23
147 forum posts
9 photos

Gary,

Your firebox looks quite shallow? Your fire door for introducing fresh coal needs to be far enough above the grate to give some depth of fire, I would guess 1/2 to 3/4" would be about right and there needs to be similar below the grate for air to get in (allowing for a build up of ash as it burns). The door needs to close too so that the combustion air comes up through the fire and not straight in over the top.

Paul.

gary.a.ayres20/12/2018 12:11:58
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Aha... yes indeed Paul.

You'll see in my post above (the one with the pictures) that I say 'the bottom half of the firebox needs to be fixed back on'.

What you are looking at above is only the top half of the firebox, which I took off to drill and tap the bolt circle for the top plate. The bottom half (which I'll be putting back on as soon as I have made some finishing touches to the top plate) has the bottom half of the firehole plus an opening for the ashpan below the grate already roughly cut out.

This is all currently in very rough form for a test firing to see if the boiler will actually run on solid fuel, but it will have a makeshift cover to close the firehole as you describe. I'll post pictures once it's back together, and if it all works I'll tidy up all the openings etc which are just roughly cut out at present, and fit a proper door.

Cheers,

gary

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