Dreaded leaks

[wafflesParticipant @waffles]

Hi. I have recently acquired a Winson/Modelworks 45xx in 7&1/4. Silver soldered copper boiler.

https://www.stationroadsteam.com/7-14-inch-gauge-gwr-45xx-4-6-2t-stock-code-13011/

Having done a hydraulic test on it myself, there are 3 small pinhole leaks around the fire hole door which do not close up when under steam. Silver soldering is pretty much out of the question as I would most likely end up chasing holes around rather than fixing them, not to mention the heat required for such a boiler would be immense. I’ve had three other suggestions, Tig welding, Comsol and punching the joint with a round ended punch to spread out the metal and close the gap. The holes are between the copper and the solder joint so punching could well work and I wouldn’t lose anything by trying that first. Comsol should work in theory. It depends on the temperatures a bit. Tig welding is something I have not done but has the same issues as silver soldering to my knowledge.

I do have another issue. The engine apparently has steam blowby. I couldn’t say where exactly as I have not had the chance to run the engine up on air. If its the valves then they will just want lapping as it appears to be slide valves on this engine. Cylinders I would presume means worn rings. I don’t know if they are cast iron or silicon O rings but as the engine does not seem to have done all that much running, I would expect silicon. Would anyone have experience with such a problem on ModelWorks engines know the likely cause and a solution?

J.

 

[Nigel Graham 2Participant @nigelgraham2]

I doubt TIG welding would work. Welding copper properly demands “de-oxidised” quality copper, and anyway the silver-solder would contaminate the weld.

Comsol ought be satisfactory if you can get it into the joint, but your friendly local boiler-inspector might be wary of it. He or she might wonder about the state of the rest of the joint.

 

If the locomotive has not been run much, worn piston-rings seem rather unlikely, but silicon O-rings may be “weaker” than iron ones. Such rings should of course be of a grade suitable for reciprocating seals. Or one was damaged in its installation.

I’d investigate the valves first as requiring less dismantling for inspection.

Leaky surfaces apart, the main source of possible blow-by with a slide-valve is the valve unable to “float” properly in its mounting arrangement on the spindle. Either by excessive tightness, or a design flaw. So once you’ve lifted the covers, test for that float first.

I add the latter reason having encountered a Winston’s Kit steam-wagon that had no way of stopping it, we discovered due to a design weakness compounded by poor manufacturing, of its slide-valve regulator!

[DurhambuilderParticipant @durhambuilder]

Some people have had success with loctite290 in similar situations. As long as the joint is structurally sound this will seal any tiny pinholes. Google ‘steam boiler leak loctite 290’.

[noel shelleyParticipant @noelshelley55608]

It’s a Modelworks so almost anything is possible ! I would be tempted to try caulking first IF the rest of the joint is sound. The best advice is to speak to your boiler inspector but not all boiler inspectors have the same views on how a job should be done or what they will accept.

3 leaks in a small area calls into question the soundness of the joint overall.

TIG welding would be out of the question.

Good luck.  Noel.

[Nigel Graham 2Participant @nigelgraham2]

If I were to test it after the repair I think I would give it a cautious [WP X 2] hydraulic test, but with long stands at working-pressure then 1.5WP on the way up.

Reason- as Noel says, what is the rest of that joint like?

[Paul LousickParticipant @paullousick59116]

I’ve never tried it but would car radiator stop leak work ??

[noel shelleyParticipant @noelshelley55608]

Back in the old days all sorts of materials were used in boilers to seal minor leaks, oat meal comes to mind as one. Fullers earth is another. I once had a radiator that was leaking repair it’s self due to being topped up from roadside puddles. Noel.

[duncan webster 1Participant @duncanwebster1]

Amongst materials I’ve seen recommended for sealing leaks are egg white for radiators and horse muck for boilers.  With steel boilers, if you fill with water, wait till water seeps from any leaks, drain if out and wait a week or so, rust seals the leaks.  With the OPs boiler, it has presumably passed a 2 times test at some point, so its integrity is proven, Alec? Farmer used to recommend Comsol for situations like this, and he was at one time the guru for model boilers

[noel shelleyParticipant @noelshelley55608]

In the cool light of day I now see the 3 little circles !  After VERY careful cleaning up, use a flux and comsol. A good fillet will form in this location. Plenty of heat will be needed even for comsol at this point, you’ll know when it’s hot enough as the solder will flow and wet the surface. It may well have passed a 2xWP test with flux plugging the holes, these have now dissolved. The cause was quite possibly insufficient heat and or (it’s Modelworks remember) insufficient silver solder. Good luck.  Noel.

[wafflesParticipant @waffles]

I’ve spoken to almost everyone with experience of steam engines in my local club, including our boiler inspectors. Of course, every one of them gave different answers. Only one person suggested tig welding. I will take whatever advise they give me with a grain of salt in future.

Caulking is as I thought, is probably the best first thing to try as nothing is really lost if it doesn’t work. It was also suggested as a first option by the better of our boiler inspectors along with Comsol if that doesn’t work. I hadn’t really thought of loctite. The two I’m seeing for that are 290 and 648. 648 being a thicker liquid so would be harder to get into the joint.

The joint appears to be structurally sound. Ive had it up to 1.5xWP 2 times for about ten minutes or so each time and once a bit nearer to 2xWP. There were no other leaks on the boiler itself and the 3 leaks around the firehole door did not get any worse.

It would appear like I’ve got some work to do and will report back after. I wont actually have a chance to work on the engine till Saturday, so I shall do some more research till then.

[Bill DawesParticipant @billdawes]

As a matter of interest my new Western Steam manufactured boiler has this info in the manual.

Filler material Easy Flo 2 or equivalent BS EN 1044 AG303.

Flux Easy Flo or equivalent.

Welding process TIG (GTAW) filler rod BS 2901 C7.

I am aware of what TIG is but that’s it so don’t know how this relates to the whole process.

Maybe a welding expert could enlighten us.

Bill D.

[Nigel Graham 2Participant @nigelgraham2]

That suggests a welded shell with the bushes silver-soldered into that.

[Bill DawesParticipant @billdawes]

Probably Nigel, the original Emma Victoria boiler design, the one I unsuccessfully made, was made up from the shell being cut at the firebox end, one side folded down to for the whole firebox side, the other folded down partly with a make up piece for the rest of that side.

Helen made it with the round shell (TIG welded?) onto the firebox and very nice and neat it looks too.

Bill D.

[wafflesParticipant @waffles]

I decided to work on the blow by issue first as I can do that without moving the engine. The engine does turn over but needs about 40psi to even start turning its wheels and I had to open the regulator pretty far as well. I wasn’t getting enough air to keep it running though unfortunately. There was air leaking out of the cylinder end caps as it would appear that the gaskets have perished. There was also air blowing by the left piston and quite badly at that. The piston itself isn’t a bad fit but I had it out anyway.

The rings are cast iron by the looks of it which is good. However, the rings were completely stuck in with very small amounts of rust. I did manage to prise them open and get them free and then promptly put some oil on and moved the rings about to get it in to prevent that happening again. I would assume then that that was the problem and why it was blowing by. I cannot yet test it as I did unfortunately find that the piston valves were also blowing air very badly. It was not difficult to see why if I’m honest. They were both a rattle fit in the holes. No good. Having taken them out, I was quite surprised to see what seems to be nylon.

I didn’t really play around with them like I did the cast iron ones so it may be that they are just stuck in. I’ll have a look tomorrow but that may well not be the case. It might just be me but I’ve never actually come across nylon rings before so I’ve no idea how good they are. That is assuming that they are in fact nylon. If the rings turn out to be scrap, what would be a good replacement?

One more thing for today. I can’t seem to find where the serial number is stamped on the boiler. I know what it is from previous certificates and that it should probably be on the backhead but I can’t actually find it myself. Does anyone know where it’s likely to be?

J.

 

 

 

 

 

[noel shelleyParticipant @noelshelley55608]

The piston valve rings or packing should be .PTFE.  Noel.

[Nigel Graham 2Participant @nigelgraham2]

As Noel says – PTFE not Nylon for piston-rings and rod seals.

Boiler serial number location: The most likely location is on the backhead or throatplate at foundation-ring level, or at the top on the rim of the shell above the backhead flange (not ideal place if stamped). The last location would be hidden by the cladding on the complete locomotive.

Perhaps along the side of the firebox at foundation-ring level.

Another possibility, though unlikely and certainly a very poor choice, is somewhere on or around the smokebox tube-plate or the barrel in that area.

[noel shelleyParticipant @noelshelley55608]

Serial number ! My Modelworks 9F has it stamped on the backhead lower left. Noel.

[waffles]

On waffles Said:

One more thing for today. I can’t seem to find where the serial number is stamped on the boiler. I know what it is from previous certificates and that it should probably be on the backhead but I can’t actually find it myself. Does anyone know where it’s likely to be?

J.

It is a little worrying that a boiler with previous certification now has leaks and a detailed examination of by an inspector could be necessary to check there are no more problems developing.

 

 

 

 

 

 

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