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Vertical Boiler Fittings

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Neil Wyatt07/10/2018 21:04:24
14723 forum posts
628 photos
72 articles

I'll echo that sentiment, well done Gary.


gary.a.ayres07/10/2018 21:13:02
68 forum posts
42 photos

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...


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

Paul Kemp07/10/2018 23:51:20
98 forum posts
4 photos


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.


geoff walker 108/10/2018 09:11:58
242 forum posts
99 photos

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!!!


gary.a.ayres08/10/2018 10:26:55
68 forum posts
42 photos

@ 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
68 forum posts
42 photos

I did a test firing on methylated spirits this morning. It seemed to go quite well:

gary.a.ayres16/10/2018 23:23:51
68 forum posts
42 photos

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
98 forum posts
4 photos


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!


gary.a.ayres17/10/2018 06:41:57
68 forum posts
42 photos

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...



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
13722 forum posts
1282 photos

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
68 forum posts
42 photos

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
68 forum posts
42 photos

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
68 forum posts
42 photos

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...

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