leaking boiler?

recently bought a 1" Minnie engine, pressure tested it and its leaking from one of the tubes inside. how can I get sorted? bit disappointed as this was my first 'proper' steam engine.

Is the leak in the sidewall of the tube or at the end at the tube plate ?

Any pictures?

Join your local model engineering club and speak to the boiler inspector. If you attempt a repair and then can't get a ticket for it you could make a bad situation worse

Terry,

Duncan's advise is sound re getting a club boiler inspector involved and as Paul asks you really need to give more detailed information to get an informed reply. Is the leak at the firebox end or the smokebox end, how bad is it? Can you maintain the test pressure on a pump with just a weep or is it streaming out and you can't hold the pressure at all?

To give you some info assuming it is a copper boiler which is silver soldered sadly it is not usually possible to make any long lasting repair if the leak is where it is likely to be which is the soldered joint of the tube to tube plate. Some will claim it is possible but if the boiler has ever been steamed there will be scale / corrosion or even products of combustion in the interface between tube and plate which is impossible to properly clean and get a proper full penetration solder joint. In addition getting the heat to the joint will undoubtably disturb adjacent tubes and like as not cause more leaks! It may be possible if it's silver soldered to clean around the joint and run a fillet of high temp soft solder (comsol) round it to get a seal that may last a few seasons.

That said, how bad is the leak, is it just a bead of water, a slow drip or a steady stream? Depending on how bad the leak is and having a pragmatic and informed boiler inspector if it's just a bead it may still pass a hydraulic test. On a risk basis if the joint lets go altogether what is the worst that can happen? It will put the fire out, may send a jet of steam out the firehole door or up the chimney but it's very unlikely to lead to a full blown spectacular catastrophic failure! I have a copper loco boiler that has a slight weep from a top tube in the firebox on a cold hydraulic test but when hot it seals and there is not a whisp of steam, it's been like it many years and has never got any worse. So before doing anything get it looked at by an experienced inspector. If it's just a pin hole in the silver solder it may be possible to peen it over to seal it. Better to look at the easy, cold options first before trying to wade in with a blow lamp! Another dodge if it's a pin hole is to steam it up using water in which you have boiled potatoes, the starch in the water will be carried into the hole and if you are lucky seal it! No doubt there will be people who will hysterically react to these 'bodges' but these will be the people who have little or no experience or have never witnessed a full size boiler hydraulic test.

Worst case scenario if it's a decent leak and the joint has completely failed is a new boiler. From your other posts I deduce that you have bought this engine without any assistance or advice from someone with some experience and are now sadly reaping the benefits of not knowing the pitfalls. Buying a steam engine without any certification is a lottery unfortunately.

Paul.

The tubes can be plugged to stop the leak. (taperred plug at each end of the tube, joined together with a threaded rod). This will allow the boiler to still operate but at a reduced capacity enabling you to still run the engine.

As stated above, best to talk to a club inspector about options

Paul.

Hi Paul, I got the pressure up to 40 psi and the water started a fast drip from the firebox end. No ,it doesnt hold the pressure. I bought this after being told it was steamed a couple of times in the past and was just an ornament now? I wasnt to worried about certificate because I didnt intend to use it in a public place, just for my own safety.

I contacted four clubs up to around fifty miles away, one was quite near, running locos every Sunday for the public to ride on etc and I asked who inspected their boilers and would they do mine at whatever cost and they said they dont know anyone who could do it?? Only one other bothered to even reply and Im not sure they even do live steam?

I have no problem stripping it and sending the boiler away to repaired or whatever,its finding someone who could do the work?

The boiler looks like brass?

thanks all for your help

Besides plugging the tube you could sleeve the tube and not lose to much capacity.

If it's brass it's a scrapper anyway, not suitable as a material for boilers. Do you know it's from a tube/tubeplate joint and not from tubeplate/wrapper joint?

Edited By duncan webster on 13/06/2018 09:13:10

I would post a pic but cant find any link?

If it is scrap then thats it for me bud.....

This is interesting - there is a chap on the mamod toy steam forum called slash 1953 with exactly the same problem

Boiler looks as if it is made of copper from his photo.

LOL! thats me bud. Firebox is copper but i scraped paint of the boiler and its brass or is that a cover? its looking like a scrapper?

could well be a cover, many (most) boilers have lagging and a thin brass wrapper over that

Does look to be the same, you need to clean up one of the flat surfaces as the metal around the joints, stays and tube ends will be coated in silver solder and look more like brass than copper.

The bit that is painted green in your avitar will be brass.

But if it is brass you are in the right place as Mamod boilers are brass

Edited By JasonB on 13/06/2018 10:12:06

Jason,I removed a bit of paint underneath at the smokebox end. I would like to find someone who could repair it if pos. I have no problem stripping it down?

Paul,just a thought,you suggested using water with starch in it,what about the addative you can use to put in the water system of a car to seal leaking cylinder heads,would that be worth a try?

A club boiler inspector probably won't inspect boilers of non club members.

Ian S C

Terry, where are you?

Hi,Im in Stevenage

Terry

If you want a boiler certificate for it, you will have to join a club. The various Associations/Federations to which clubs are affiliated have an arrangement with Royal & Sun Alliance to certify boilers, but you must be a Club member for it to work. Even if you have a valid boiler certificate but are not a bona fide club member, the certificate and its covering insurance will be invalid.

Obtaining an independent certificate from somebody else would be nigh on impossible. Where, they would ask sternly, are your certificates of conformity for the materials used in the boiler construction? Where, they would continue, are your calculations for the design of the boiler? Etc, etc. Don't go there. It would cost you a fortune anyway.

Provided the club boiler inspector is happy with it, (and if the boiler has any brass in it he won't be), then he may be satisfied with just a small weep or else ask for it to be expanded in place (tapered drift should do it as it's annealed - but don't overdo it) or else as suggested before, run some Comsol around the joint. If you try to silver-solder it then as said previously, you'll have problems with it because a) it probably won't run as it's already got nasties in the joint and b) you'll probably start melting and cracking adjacent joints. Also c) you'll need something special in the way of torches to get into that tiny firebox to put enough heat into it. Luckily it's one of the lower tubes, so you may be OK

A good seeing-to of the affected area with a bead blaster immediately before trying any kind of soldering operation would be your best bet. But bear in mind that bead-blasting might actually remove some bits of gunge on an adjacent tube and cause that one to leak... Good luck.