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Juliet boiler

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Tomek29/09/2020 19:58:41
21 forum posts
10 photos

Hello all!

I'm about to buy a boiler for my Juliet II. It has been made by South Devon Steam back in 2014 and never been steamed. It is CE stamped and seller has got original paperwork. I've asked for few photos and it seems to be all fine. Just one thing caught my attention, if you look at the smokebox tube plate green stains can be seen on joint in lower left and top right of the joint. Is this something I should be worried about or just natural thing due to storage? At the moment I'm not the member of any ME club but I believe that when I join (after pandemic) boiler inspector shouldn't have problem with renewing certificate? Correct me if I'm wrong.

Any help will be much appreciated.








Bazyle30/09/2020 00:51:39
5479 forum posts
206 photos

The stain would just be a bit of flux not quite cleaned off, or a fly that died there. In some ways it is actually better that it seems to be 'as found' so that such stains can be seen rather than tarted up with a wire brush and a bottle of brasso.

Tomek30/09/2020 09:56:49
21 forum posts
10 photos

Thanks Bazyle. I thought that might be flux left over after soldering.

Any idea on the retesting? Would it have to be a bare boiler with no fittings or can it be retested on the loco?

J Hancock30/09/2020 12:39:36
452 forum posts

I am sure it will save any 'problems' if you have the boiler hydraulic tested 'bare'.

Just a suggestion, use anything but the 'disc -in-a-tube' for a regulator .

Tomek30/09/2020 12:47:48
21 forum posts
10 photos

I haven't decide on the regulator just yet. Can I ask why you're against a disc type regulator? Wouldn't they shut steam properly or maybe tend to seize?

Another option would be needle type regulator which is probably easier to build anyway.

J Hancock30/09/2020 14:19:26
452 forum posts

At this size , a 'screw' type regulator will be more reliable , stainless screws in the end bushings too.

You may find an 'O' ring type connection at the tubeplate end a better proposition as well.

J Hancock30/09/2020 14:26:24
452 forum posts

One last point.

I notice no provision has been made for a firehole door hinge.

Think carefully how you want to approach the solution.

Drllling and tapping holes in the backhead at this stage can be fraught with problems.

Tomek30/09/2020 14:29:53
21 forum posts
10 photos

I definitely wouldn't attempt drilling into a backhead. I was thinking about brass plate to go over backhead witholes for all the bushes and solder hinges to it.

Nigel Graham 206/10/2020 22:04:08
748 forum posts
16 photos

I don't see any problems having it tested. It's an identified and certified specimen of a known design, you have all the paperwork.

The MELG manual on boiler-testing describes the procedure for this situation, and if you don't have a copy it I would suggest you obtain one so you know what is expected.

Essentially the test is in two phases - the cold hydraulic one, and the steam-accumulation test. The latter can only be done on the complete loco of course, as it observes the performance especially of the safety-valves, also the gauge -glass(es), pressure-gauge and feed arrangements.

As Bazyle says, the green spot was probably caused by a trace of flux.

I'm surprised it has no mountings for the fire-hole door, too. You could as you say make a cover-plate for the whole back-head but I have been trying to think of a better way! The boiler-inspector you eventually meet might be able to suggest a solution once he has the boiler in front of him.

One tip - clean those rags of PTFE tape out of the threads before installing the new test-plugs / fittings. Advice I have received, at a boiler-testing seminar, is that fibre or copper washers are preferable to PTFE tape, too, because bits of tape in the boiler can become carried over into places like the gauge-glass passages.

(Whilst accepting different applications and conditions, a professional plumber and gas-fitter told me he uses barely a reel of PTFE tape in a whole year!)

Tomek06/10/2020 23:43:09
21 forum posts
10 photos

Thanks for that Nigel. Actually the boiler is only going to be delivered tomorrow as the guy I've got it from couldn't send it earlier.

When I get it, I can start making all the fittings and think how to fit the fire hole door to the backhead.

Thanks for the tip with the washers! I was going to use ptfe to be honest but after your suggestion I might go for a washers.

Jon Lawes07/10/2020 01:58:56
403 forum posts

I mounted a plate over the backhead held in place by steps on the fittings with the firehole door mounted to that. It works very well.

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