Boiler lagging help needed.

So, as my engine (3" traction) is over 10 years I have had to remove the cladding for a shell inspection.

Originally the boiler was lagged in some sort of material, then timber then the steel outer shell.

Ideally, I would have liked to use the original timber again but I don't think I will be able to.

So, I plan to wrap the boiler with a layer of kaowool with I have now ordered, is there any particular type of wood I should be looking for?

Needs to be about 6mm thick and I will need to bevel the edges for a better fit.

Thanks for any advice.

Brian,

Generally it is good to keep any lagging material from contacting the boiler directly. There have been plenty of instances where an absorbent material has been against a boiler shell, retained moisture and promoted corrosion. Problem is on a 3" there isn't a lot of space! If you are planning to use wood again it would be worth making some crinoline steel bands to go round the boiler and put the timber on top of these, which will stop the timber contacting the boiler directly.

To be honest I don't believe lagging adds much if anything to performance in engines of this size, I ran my Ruston 4" for a year with no lagging or cladding on the boiler at all and it didn't seem to noticiably affect performance. That now has cork sheet under the cladding directly onto the boiler (been there 9 years and due to be exposed next year) so I am going to very interested to see what corrosion I may have when it comes off! On the 6" I will probably use wood but spaced off as described.

Paul.

I looked at all of the alternative materials for insulating the boiler on my 6" Ruston but found that they all absorbed water and oil. The water will evaporate if the boiler is hot but this is not always the case. Oil that finds its way under the covers will not. My solution was not to use any material under the covers and to support them on thin metal spacers to trap air beneath. (Air is an excellent insulator if contained). Anything that finds its way under the covers will run out at the bottom. The covers are warm but not hot to touch when the engine is running.

See previous post: **LINK**

Paul

Edited By Paul Lousick on 25/05/2021 08:04:02