Cylinder Lagging

[Alan Worland 1Participant @alanworland1]

[Alan Worland 1Participant @alanworland1]

My current steam engine calls for a brass sheet wrap around the cylinder as lagging but I would prefer to use timber.

I have aquired strips of a suitable timber material which measures about 5 or 6mm wide by a couple of mm thick which I was proposing to hold in position with a couple of stailess steel straps.

My question is, is this the correct way to do this? as I am a bit concerned that the wood will move with heat/damp and not look so good!

Did I ought to make the strips out of something thicker which more followed the 'cotton reel' type shape of the cylinder casting?

Any guidance/advice wout be very welcome

Alan

[SpringbokParticipant @springbok]

Hi Allen,

A number of questions, firstly what is the steam engine and it's scale. . I have been doing a lot of research into moldable lagging materials of recent and hope to present this to all on forum.

Bob

[Sub MandrelParticipant @submandrel]

Tom Walshaw used to stick the lagging strips to thin material (such as an old cotton hanky) to keep them in line. I just glue them on one at a time with superglue.

Perhaps not the neatest job, but they haven't moved when run on steam. 1/12 scale, so about 1 1/8" diameter at the flanges.

Neil

[Alan Worland 1Participant @alanworland1]

Bob, my model is a horizontal engine, 1 1/2 bore and 2 1/2 stroke and I would say the diameter of the cylinder flanges which will take the lagging is about 2 1/2 diameter.

I did even consider filling the recessed part of the cotton reel shaped casting with car filler or JB Weld so as the strips would have something to stick to!

Neil, have you stuck them directly to the casting? or did you use a membrane? and are they oiled or varnished?

Alan

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

Hi Alan ,

Random thoughts :

(1) Fullsize engines with wood lagging almost always had the interspace packed tight with insulation material .

(2) Tufnol and Paxolin work much better than real wood on small engines – much stronger and almost unaffected by moderate heat or water and oil .

(3) I've lagged several engines using tufnol by deeply scoring a sheet with 'planks' and then heat moulding the sheet into a curve to fit cylinder .

I did Neville Evans prototype Loch boiler in a similar way even though the 'wood' lagging was finally covered with metal sheet .

(4) Wood lagging on smaller workshop driving engines like yours was actually quite a rarity . Most common was ductile blue steel plate .

Regards ,

Michael Williams .

Edited By MICHAEL WILLIAMS on 16/03/2012 22:27:36

[Alan Worland 1Participant @alanworland1]

Thanks Michael, I have myself used stainless steel on a previous engine (in my photos) which I thought looked quite good and I have an early Stuart engine which is lagged with blued steel which also looks good.

I do have some sheets of SRBP which I could have a play with but it might look a bit 'bland'? The Tufnol sounds the better bet as it has the woven texture to it.

Is there a filler which might survive stuck to the cylinder under my timber?

Alan

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

Hi Alan ,

There are no doubt fillers which will stand moderate steam temperature but I prefer to use a mechanical solution .

Basically make either the lagging or something under it self supporting .

Possibilities are making the lagging quite thick or in two layers – possibly with rebates at ends to clear end flanges .

Or arrange , as in some full size engines , one or more support hoops .

The trick on small engines really is to make the lagging as a piece of tube so that its shape gives most of the stiffness needed .

Regards ,

Mchael Williams .

 

Edited By MICHAEL WILLIAMS on 16/03/2012 22:57:03

[SpringbokParticipant @springbok]

Hi

What I was thinking about doubt it would be of any use to you but the cotton strip idea sounds good

now I have seen a pic..

Bob

[JasonBModerator @jasonb]

I';ve used the stick it to an old hanky method, just lay the fabric onto a sheet of polythene(non stick) coat with exterior pVA wood glue and lay teh strips onto it. When all is dry trim to size and wrap around cylinder then retain with metal straps.

The minnie in my avitar has balsa strips done this way below the brass clading sheets and this beam has the wood exposed.

If you want to fill the space and are going to steam run it then fill the void with an insulating material like Kaowool.

If you want a filler that will take the heat then JB Weld will do but won't actually add any insulation value.

J

[Richard ParsonsParticipant @richardparsons61721]

There was some stuff used by jewellers which you mixed with water and slapped on jewellery to protect it when silver soldering. I think H.S. Walsh sell it (usual disclaimer)

Rdgs

Dick

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

Discussion of lagging has stirred a few memories :

(1) A poular material for cleading full size cylinders and boilers was Russian Iron . This looked like blued steel plate but the material was in fact a refined form of wrought iron . Very easy to cut and bend and had the useful property of bending with very little springback – so was easy to form around complex shapes . Made a sight crackiling sound when bent – like transformer stampings . Russian Iron was at one time supplied by Stuart Turner in their casting sets for cylinder cleading . This material is sometimes also known as St.Petersburg Iron .

(2) There was still some steam in use when I first started in engineering – a few actual engines and plenty of heating and process plant and steam cranes . The lagging and cleading on many of these things was very variable in quality – the most popular pipework lagging by then was thick asbestos paste held in place with chicken wire .

Michael Williams .

[Sub MandrelParticipant @submandrel]

Tom Walsahw insisted that most lagging material was a waste of time in small szies, but balsa (if kept dry) was good.

In answer to the question, I just glued my strips direct to the cylinder with no other lagging. Naughty, but it worked.

The original has wooden lagging (note my model isn't accurately to scale… more sort of inspired by!)

Neil

[Brian JohnParticipant @brianjohn93961]

Has anybody else used superglue to glue the lagging to the cylinder ? I would not have thought it would tolerate the heat very well.

[Neil WyattModerator @neilwyatt]

'Service temperature' is typically about 82 degrees C, but I don't run that engine on steam for long periods – I've only steamed it 2 or 3 times, it usually runs on air. The brass strips would stop the strips falling off, the glue just held them neatly in place while I fixed the strips, I suppose.

Neil

[Brian JohnParticipant @brianjohn93961]

Thank you for that information : I will stick with my plan of using JB WELD.

What colour red is used on that engine ?

Edited By Brian John on 08/07/2015 10:49:50

[Neil WyattModerator @neilwyatt]

It's Humbrol Crimson, if I'm not mistaken, always looks more like a dark maroon to me.

Neil

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