Boston & Maine B15 2-6-0 Scratchbuild

[garethashenden]

Bit more progress today. I’ve shaped the front truck, so now the engine has all its wheels. I need to cut one side and epoxy it back on to isolate it electrically. I’ve also started working on the boiler, although no photos of it. The smokebox and rear section have been formed, taper section next then join it all up.
The screw holding the truck on it’s attached, it’s not in it’s final location which is why it’s at an angle.

[peteski]

Looks great!
If DKS was around he would likely comment about using Kato Unitrak for displaying such a fine scale model. 

[dem34]

Looks great!
If DKS was around he would likely comment about using Kato Unitrak for displaying such a fine scale model. 

Good enough for BLI good enough for us right?   

[nkalanaga]

For display?  Maybe something nicer when the model is finished.  For testing an unfinished model?  Unitrack is flat and rigid, so probably a very good choice.

[garethashenden]

Looking more like a locomotive! Although this boiler has lots of problems and I’m going to make another.

[Cajonpassfan]

Beginning to look like a locomotive🙀
Nice work, love following your thread!
Otto

[mmagliaro]

Coming along nicely, sir!
Say, is the forward section of the boiler a different a metal?  Is there a design reason for that?

[garethashenden]

Coming along nicely, sir!
Say, is the forward section of the boiler a different a metal?  Is there a design reason for that?

It’s nickel silver. I prefer working with nickel silver over brass as it’s easier to solder. The heat doesn’t spread as easily compared to brass, so assemblies tend to stay together better. Having said that, boiler Mk II is all brass. With both boilers I silver soldered the rolled sections for added strength. On the second boiler I have also silver soldered the sections together. It’s all discoloured from the torch at he moment, once I get it cleaned up I’ll post pictures.

[garethashenden]

The hardest part of the boiler is the middle coned section. I did the math this time and laid out the correct curved shaped on flat sheet. But, if I’d just rolled it up then it wouldn’t have been correct. The boiler is tapered on the top but horizontal on the bottom. If it was a true cone it would have been tapered both top and bottom. A bit of extra metal was needed at the corners on the front and middle at the back. The sheet was then annealed, cleaned, rolled up and silver soldered. Silver soldering, or hard soldering, makes stronger joints than soft tin-lead solder, but it requires higher heat from a torch.

Here is the cone marked out on brass sheet


Rolled up, held with brass wire to keep the edges together


Here we have the smokebox soldered to the cone and the cone about to be soldered to the rest of the boiler.


Soldered but not cleaned up


And mostly cleaned up.

[metalworkertom]

Looking great. Been following along with your build. I really like the fact you are using silver solder for your joints. Using Hard , Medium and Soft silver solder can make life much easier. Then adding other details with lead solder . Exactly what I am doing on a current build.

[garethashenden]

I’ve made a new set of rods, which is one of those things you shouldn’t really do. The rods and chassis are best drilled all at the same time, to make sure that the holes line up. This is essential to getting the chassis to run well. Unfortunately the sheet I used to make the rods from was rather thin and I did a pretty bad job of the fluting. I thought it was worth a shot at remaking them, using one of the originals as a master. I stacked two pieces of 0.020” steel and one of the 0.015” rods and soldered it all together. Then using the existing holes, the new blanks were drilled through. While they were still soldered up I shaped them. After separating them, I soldered them separately to a stiff piece of brass. This solved the problem of how to hold them while forming the flutes. The flutes were made with a 0.030” slotting file. It was hard to start, but got easier as the flute became more established.
In retrospect, it would have been easier to make the flutes and then shape the rods, it’s easier to bring the sides in to suit the flute rather than hoping you can line the flute up correctly in the narrow rod. It worked out this time, but I will do it differently next time. I still need to separate the rods from their brass backing and see if they fit, that can be tomorrow’s project.