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LBSC 3.5" "Maisie"

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bogus29/05/2020 09:06:58
31 forum posts
54 photos

Dear Fellows,

in order to take the boiler for cleaning and inspection i hade to take all the wrapping off the boiler shell. It turned out it was soft soldered (grrr!), including the bands "holding" wrapping brass sheets sections. To desolder them i had to head them up to the temperature at which paint came off... Not only that: firebox section was badly bent and damaged during this job.

This is my first loco and i don't have experience with sheet metal work. Could you advice me how to make a new wrapping? rounded sections are fairly easy - i'll make cardboard patterns to make all the necessary holes (for water check valves, chminey, steam dome, etc.) however the firebox section is a nightmare.

Another thing is i found the builder didn't "lined" the boiler. I don't know if it is a good word for that? I'm reffering to that thin insulation layer wrapped around the boiler shell, under the final metal sheet wrapping. I know it is to reduce energy losses and i'd like to use it when making new wrapping. However that insulation has thickness... Could you point me to the source where i can see what material is usuallt used for that? And what thickness should i use. What worries me is the fact that smokebox O.D. is now equal with original wrapping (brass sheet ca 0.5mm thick). If i add, say 1.0mm thick layer it will increase overall O.D. of the boiler by 2.0mm and it will not be equal to the smokebox O.D. anymore.
What you think about that?

Andrew Tinsley29/05/2020 09:51:56
1119 forum posts

If it is a soft soldered boiler (rather than being caulked with the soft solder, in the odd place or two) then you have a potential disaster. My advice is to scrap it and build a silver soldered boiler.

It will never pass the boiler inspection code and hence will be uninsurable. Sorry if I am the bearer of bad tidings.

Andrew.

Andrew Tinsley29/05/2020 09:51:57
1119 forum posts

Double post!

Edited By Andrew Tinsley on 29/05/2020 09:52:47

SillyOldDuffer29/05/2020 10:05:55
5798 forum posts
1235 photos

Can't help with the sheet metal work.

The boiler insulation is called 'Cleading' or 'Cladding'. It's a problem on a scale loco because effective insulation needs to be as thick as possible. 1mm will slow down heat loss but not by much, and it may not be worth the effort.

I suggest adding as much insulation as can be accommodated without spoiling the look of the model, or forcing structural changes. That might mean zero insulation. Otherwise wood, blanket, fibre glass - anything that can take the temperature.

Ideally a steam boiler would have more insulation than a domestic water tank. It isn't practical because they have about 60mm of foam insulation.

All steam locos are thermally inefficient, even full size. The general answer is to put more coal on the fire.

Dave

DMB29/05/2020 10:19:47
1003 forum posts

bogus,

Thin cork sheet is often used and would probably best suited to your need. ME suppliers sell white fibrous insulation matting special for that purpose but I think min. available is 1/4" but compressible. Could be difficult to deal with on small boiler, have you grown a 3rd hand yet, ha, ha. Cereal packet cardboard usually used for a trial pattern shape. You could possibly have to make up a thin brass ring to finish off "joint" from cleading to smoke box. Hope this is helpful, good luck and come back to forum if need to.

John

Nick Clarke 329/05/2020 10:39:07
avatar
779 forum posts
27 photos
Posted by Andrew Tinsley on 29/05/2020 09:51:56:

If it is a soft soldered boiler (rather than being caulked with the soft solder, in the odd place or two) then you have a potential disaster. My advice is to scrap it and build a silver soldered boiler.

It will never pass the boiler inspection code and hence will be uninsurable. Sorry if I am the bearer of bad tidings.

Andrew.

There is no reason to suppose the boiler is soft soldered - the original design (from 1936) was silver soldered throughout with the exception of the firebox stays which were sealed with soft solder, inside and out.

This was current practice until quite recently.

The designer of Maisie did not specify lagging of any kind over his boilers except for a sheet over the firebox to cover the stay heads (and not always then) but when asked for information he gave a description, just as you found, of a sheet, rolled around the boiler held in place with soft solder, as you note.

You are probably lucky in that no insulation was present as, depending upon when it was buillt, it might have been asbestos.

All suppliers will sell boiler lagging material which is safe in thicknesses from 1mm upwards.

Edited By Nick Clarke 3 on 29/05/2020 10:40:21

Phil H129/05/2020 11:08:02
273 forum posts
27 photos

Bogus,

LBSC possibly did not intend either lagging or outer cladding to be used!!! Hence your issue with the smokebox and boiler diameter.

I have the drawings, description and parts for 'Betty'. Betty is also a 3 1/2" gauge LBSC designed locomotive. This is a short extract from the construction notes;

'No lagging is needed over the boiler barrel, but a sheet of very thin brass or copper can be put over the firebox to hide the stayheads'. The text continues - 'Boiler bands, which hold the lagging sheets on a full size engine, can be made from narrow spring steel'. The description also suggests that thin strips of brass could be used instead of the spring steel.

Obviously LBSC didn't always see the need for the outer sheeting and insulation apart from the cosmetic covering of the firebox area. Well at least that's what he thought for Betty and I have seen other quotes suggesting that he employed this method for quite a few of his other locomotive designs.

He also describes cleaning the engine down with petrol (outside the house of course) before painting it with green Valspar paint. I assume that meant paint directly onto the copper boiler shell!!

So it looks like you have a couple of options. If the outer boiler shell is clear of dings and prangs - you could take the LBSC approach, you could put the cosmetic outer sheeting directly onto the boiler with a very thin insulation sheet underneath or you could accept insulation that brings the boiler sheeting to a diameter greater than the smokebox.

I haven't done any sums to calculate the temperature reduction with or without insulation but his engines obviously worked quite well.

Phil H

Phil H129/05/2020 11:10:09
273 forum posts
27 photos

Got there before me Nick.

Andrew Tinsley29/05/2020 11:15:08
1119 forum posts

Hello Nick,

The OP stated quite clearly that the boiler was soft soldered. Look at his second sentence. I am fully aware that stay caulking with soft solder was the norm until fairly recent times.

IF the boiler is soft soldered, as the OP says, then it is a potential disaster waiting to happen. Many years ago,I saw the results of low water level and a soft soldered boiler. It was in a model boat and when it exploded, the boat sank without trace. It was fortunate that the boat was a fair distance from shore and no one was injured!

Andrew.

Andrew Tinsley29/05/2020 11:15:09
1119 forum posts

Hello Nick,

The OP stated quite clearly that the boiler was soft soldered. Look at his second sentence. I am fully aware that stay caulking with soft solder was the norm until fairly recent times.

IF the boiler is soft soldered, as the OP says, then it is a potential disaster waiting to happen. Many years ago,I saw the results of low water level and a soft soldered boiler. It was in a model boat and when it exploded, the boat sank without trace. It was fortunate that the boat was a fair distance from shore and no one was injured!

Andrew.

Nick Clarke 329/05/2020 11:32:27
avatar
779 forum posts
27 photos
Posted by bogus on 29/05/2020 09:06:58:

Dear Fellows,

in order to take the boiler for cleaning and inspection i hade to take all the wrapping off the boiler shell. It turned out it was soft soldered (grrr!), including the bands "holding" wrapping brass sheets sections. To desolder them i had to head them up to the temperature at which paint came off... Not only that: firebox section was badly bent and damaged during this job.


I read that as meaning the cladding/wrapping was soft soldered, as LBSC, the designer suggested

If the boiler is rivetted for strength and caulked with soft solder to seal those joints it is far more complicated as, if the boiler has been tested in the past then it could have acquired 'grandfather rights' In which case, while a modern boiler would be better as you suggest, it would be up to the individual tester to decide whether to test it, and then to decide on its condition. It is unlikely that a new design would be published using this method of construction, and if not a published design the boiler inspector will need to see the design before construction starts and would probably say no at that point. But this is an existing boiler, so such criteria don't apply.

Unlike the one applicable to smaller boilers, the current boiler code does not specifically exclude a rivetted and soft soldered boiler, merely that joining procedures have been satisfactorily undertaken and all joints are sound.

Modern all silver soldered boilers are undoubtedly the way to go today, but the older methods, if sound, can still be re-tested and accepted at the inspector's discretion.

Edited By Nick Clarke 3 on 29/05/2020 11:36:30

Nick Clarke 329/05/2020 11:42:37
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779 forum posts
27 photos
Posted by Phil H1 on 29/05/2020 11:08:02:

He also describes cleaning the engine down with petrol (outside the house of course) before painting it with green Valspar paint. I assume that meant paint directly onto the copper boiler shell!!

It is a long time since I read the 'Betty' book but as far as I recall after washing down in petrol and painting with Valspar, a brushing cellulose, didn't he suggest leaving it in front of the fire to dry and then, to get gold letters on the tender, suggest chipping the paint off in the shape of the numbers etc. leaving the brass showing through.

I think some etching primer might have helped here by the sound of it!!!

J Hancock29/05/2020 11:45:10
410 forum posts

Thermal conductivity figures as 'k'

copper 380

cork 0.052

wood (oak) 0.147 to 0.216 Balsa would be more like cork figure.

felt 0.03

If 'economy/ heat loss' was the criteria then a thickness of 60mm is recommended for a 100mmOD pipe.

In other words, it probably doesn't make much difference lagged or not !

Phil H129/05/2020 12:44:19
273 forum posts
27 photos

Nick,

Not sure about the cellulose bit - I can't spot that at the moment but yes, chipping the paint to reveal the brass lettering is one of his suggestions. All a bit crude but he built quite a few engines and got them running - and did quite a few drawings too.

Andrew, perhaps Bogus will be back to confirm but I am reading this the same way as Nick i.e., this thread is all referring to some thin brass cosmetic cladding that has been soldered over the top of the boiler.

Phil H

Andrew Tinsley29/05/2020 13:07:44
1119 forum posts

Phil and Nick,

Maybe you are correct about the soldering being simply for supports for the cladding. I read it as being a soft soldered boiler.

I am very surprised that a soft soldered boiler is allowable these days. The one I saw self destruct, was soft soldered and riveted. After that incident, I would never want to be near such a device in steam, boiler ticket or not!

Andrew.

bogus29/05/2020 13:18:34
31 forum posts
54 photos

Guys,

by telling "it was soflt soldered" i was reffering to the WRAPPING only not the boiler itself Boiler is silver soldered for 100%.

Here's the boiler AFTER i removed the wrapping brass sheets. The below photo was taken during the cleaning. You can see, at the lower right corner of the firebox crown fundation (is it good naming?) - it is soft solder. It looks like someone was repairing that? On the forum i heard that was/is the normal practise. Is it?

img_20200505_195221.jpg

Here is the boiler after i cleaned it:

img_20200507_234100.jpg

img_20200507_234133.jpg

For cleaning i used soda blasting technique - never heard someone using it for boiler cleaning but it is completely harmless for boiler elements and solders. I had weak compressor available and the cheapest "sandblasting kit" so it took a while to clean it and the cleaning process for sure can be stronger when using better gear, however i'm pretty happy with the result. What you think? The good thing about soda is it is not aggresive, user friendly (eventually you can brush your teeth or bake a cake with it) and after cleaning just put boiler in water to dissolve any soda leftovers.

Another view - preparation for cleaning:

img_20200504_181935.jpg

Inside of the firebox - do you thing these whiteish thing on the stays are the signs of leak?

img_20200501_172738.jpg

img_20200501_172730.jpg

Smokebox side after cleaning:

img_20200507_234115.jpg

 

Thank you for explaination guys. If i manage to find 1mm thick insulation material i think i'll try to use it as i need to make new wrapping anyway. Smokebox is ordinary mild steel. Maybe i'll make slightly bigger one to accomodate O.D. increase of the boiler?

Edited By bogus on 29/05/2020 13:19:26

Nick Clarke 329/05/2020 13:30:41
avatar
779 forum posts
27 photos
Posted by bogus on 29/05/2020 13:18:34:

Thank you for explaination guys. If i manage to find 1mm thick insulation material i think i'll try to use it as i need to make new wrapping anyway. Smokebox is ordinary mild steel. Maybe i'll make slightly bigger one to accomodate O.D. increase of the boiler?

Edited By bogus on 29/05/2020 13:19:26

Reeves 2000 sell ceramic paper 2mm thick, GLR Kennions sell it in 1mm and 3mm while Blackgates sell it in all three thicknesses

Phil H129/05/2020 14:32:20
273 forum posts
27 photos

Bogus,

Difficult to tell for certain but that looks like it is fully silver soldered because the side stays look like snap head rivets? I suspect you know this but it needs to be seen by your local inspector before you go any further (difficult at the moment I know).

The chassis in the background looks nice.

A soft soldered repair - if it is soft soldered repair might have a hard time with your inspector.

Phil H

bogus29/05/2020 21:03:52
31 forum posts
54 photos

The problem is there is no live steam models boilers inspectors around me. ZERO. In Poland there is no live steamers clubs or associations. No market for that. We had different problems in the past...

Now i'm collecting necessary taps and dies to make plugs and new fittings. Some of them broke when trying to undo threads! What i dont like is the way hand rail going along the barrel are fitted to the boiler. These are screwed into the boiler body directly! I bet someone used glue for that as all of them need to be lined-up accurately to pass the rail bar through the holes. Unfortunatelly some of them are broken. How to fix it? I plan to drill and cut new thread in the boiler shell (the shell is 3mm thick i think) and screw in plugs using Locktite (high temperature). These plugs will have blind threaded holes for new handrail fittings - this way there will be no problem with leaking handrails fittings. You can see these small threaded holed here:img_20200501_184944.jpg

img_20200501_185016.jpg

And some broken fitting - boiler water feed check valve:

img_20200501_181537.jpg

BIG QUESTION: how to remove scaling from the inside of the boiler? It is not bad, but i'd like to descale it / remove "limestone". I know the broken feed valve is showing a lot of scale but i've check inside with boroscope and looks good. I have a problem with regulator but i need to start new thread as it is quite different story.

 

 

Edited By bogus on 29/05/2020 21:04:18

Paul Kemp29/05/2020 22:12:20
485 forum posts
18 photos
Posted by Andrew Tinsley on 29/05/2020 13:07:44:

Phil and Nick,

Maybe you are correct about the soldering being simply for supports for the cladding. I read it as being a soft soldered boiler.

I am very surprised that a soft soldered boiler is allowable these days. The one I saw self destruct, was soft soldered and riveted. After that incident, I would never want to be near such a device in steam, boiler ticket or not!

Andrew.

Andrew,

I also read it as the OP wrote in that it was the cladding not the boiler.

I am very interested in your account of the boat boiler you described in your earlier post can you provide more detail?

Initially you said it was "soft soldered" and failed due to low water level - an entirely understandable situation and common to many small soft soldered boilers going back to Birmingham Piddlers. It is fairly obvious that a purely soft soldered boiler would fail in this manner and you may be surprised how many of those are still around in the form of vintage toys!

However you now state it was rivetted and soft soldered? There is nothing fundamentally wrong with this type of construction assuming the rivets are properly sized and placed, the properly correct description is rivetted (to take the stress) and soft solder caulked (to seal any leakage path) and there are a good few of those still in service and perfectly safely too.

Assuming the boiler was as it should be for a purely soft soldered unit of small volume with a low working pressure its failure in a lightly constructed model boat could concievably sink it and be capable of inflicting minor injury (which is why this construction is no longer really acceptable, particularly for new builds) but operated correctly with adequate water level is unlikely to fail catastrophically if properly constructed.

If it was rivetted and soft soldered it would likely be a higher volume and pressure but again unlikely if properly constructed to fail in the manner you describe even with low water level. The more likely scenario is a leaking jet of steam from a melted solder caulked joint, the rivets would have prevented an explosive failure.

So which was it? Soft soldered or rivetted and soft solder caulked?

I would add that even a silver soldered boiler is not imune from failure in the event of operating with a low water level and can be just as, if not more dangerous as higher temperatures and most likely pressures are involved.

I would suggest it was the clown operating it with a low water level that was more dangerous than the boiler!

Paul.

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