Lagging. As in boiler insulation, not as in failing to keep up. I have been working on the boiler for about 3 months, so I am actually happy with the progress. And more than happy to have passed certification!
I decided to apply wooden lagging strips for the appearance and for ease of handling, rather than any minimal improvement in performance of the boiler.
After use, the boiler shell is too uncomfortably hot to handle, so there is a waiting time of 30 minutes or so to allow it to cool. I am hoping that wooden lagging will reduce the waiting.
And wooden lagging will hide the splodges of silver solder around each boss and join. And it looks the part IMO.
But how to attach it? None of my books mentioned any method. I presumed that the brass strips are the main method, and that is certainly so, on full-size boilers. Then I found a short video on YouTube by Keith Appleton and I decided to copy his method.
The method uses Super Glue as a temporary securing method while positioning the strips, then applying brass strips to hold the wooden strips in place long term. The boiler heat and expansion-contraction will result in the glue bond being temporary, and if the wood strips have to be removed later, for any reason, that will be possible. It also means that an insulating blanket cannot be inserted between the copper shell and the wooden strips, but I was not planning on using a blanket, so not a problem.
The strips are 3x8x265mm. I chose Tasmanian Oak which is actually an ash, because it is hard, fine grained, and I had some in old floor boards. I cut the pieces to length a bit oversize, then ripped them to size on the bandsaw. It is difficult to avoid fingers being close to the blade with small pieces like this, so I used a push stick. I needed 65 pieces. The blade teeth are a bit too coarse for this job, but I was too lazy to change it for a finer one. Note the saw blade guide. I did not like the one which was provided by Metabo, so I made that one. Works well!
Then I used a belt sander to remove most of the sawing marks. The resulting thicknesses varied from 2.8 to 3.4mm but I hope that variation will not matter.
Some hand sanding to remove wood fur.
That was yesterday. Today I hope to complete this job, but SWMBO is home, and not appreciating the dust and mess, so I am exiled to the outside.
I have realised that to secure all of the wooden pieces I will require 5 brass bands. I do not want it to look too brassy, so I am ordering narrower strips than the 6mm material which I had previously bought. I think that 4.75mm will be about right.