Brake gear.

A problem with all systems where power is picked up from the rails is that brake shoes realistically close to the wheel treads need to be isolated from those on the other side and from the frames, or else short circuits will occur. DC or DCC, I think. Now my system is going to have no pickups from the driving wheels, but the brakeshoes as made in the kit will short-circuit from one side to the other. What options do I have?

My first thought was to make new brake hangers by acrylic/epoxy molding. So I bought a Sylmasta kit and made molds for the brake hangers for the locomotive and tender.

I then made castings first in polyester (this was the plastic/resin provided in the molding kit):
These were too friable and brittle, however, so by default I tried molding in Araldite, which was more robust, but full of bubbles:

Even these looked unlikely to survive very long in general use, though. Contacting friends for advice suggested that I was trying to make castings of too much: it would be better to make castings of just the brake shoes.
However to do that meant filing all the brake shoes off the hangers (fourteen!) and both making and fitting accurate copies of the shoes onto each hanger. Then it occurred to me – I don’t need to take all the brake shoe off, just the surface which will be in contact with the wheel tread.
So I found some 2mm wide Plastikard strip, and have carefully filed sufficient off the surface of the brake shoes to glue a strip of Plastikard onto each shoe.

So the one on the left has been filed back, and the ones on the right show the Plastikard in place.

Once I came to try to fit them to the frames the next adjustment became necessary. As the frames are set at nearly the correct prototype width, they are much closer behind the wheels than in Finescale. If the brake hangers are fitted as made, the hangers are too far away from the frames, the shoes are outside the wheel rims and the outside parts of the shoes contact the coupling rods and stop them rotating. So now I became more grateful that the main parts of the brake hangers are metal, not epoxy! The two on the left of the picture above have had the posts from which the hangers are suspended shortened, whilst the right hand one is the original length. I think that this adjustment would have been near-impossible using plastic parts.

Now I just have to fit them, one or two at a time, and make sure the wheels still go round after each fitting.

Just an update.  Partly because of the difficulty painting behind the driving wheels, and partly because I realised that I needed to put the balance weights on the wheels (and this would probably be much easier if I could lie them flat), I partly dismantled what I had done so far to put together the chassis.  Also I realised that the return cranks were on at an exaggerated angle, and although this makes the valve gear move more satisfyingly, I should probably re-do the soldering to make it more realistic (10 degrees is right).

Of course to put the balance weights on is easier said than done. First of all I had to choose exactly which 8F I wanted to model! I found a picture of number (4)8067 which seems to have the right characteristics: a rivetted tender, balance wheels of the earlier type (not all of the weights are crescents) and based in the north of England. So number 8067 it will be.

Both types of weights are supplied in the MOK etches, as pairs (so four of each shape). Using the S7 Group Slaters wheels makes sandwiching the pairs of etches together relatively easy, one on each side of each wheel: the plastic spokes can be cut back a little to accommodate the etches. Not too much on the outer side, though, as the balance weights stand proud of the rims on the pictures I have seen.

I then filled in the gaps between the etches with Milliput filler.

Now seemed a good time to use Birchwood Casey metal black on the rods and valve gear, to obtain a good “polished steel” finish. I used Hi-Chem “All-Surface Primer” on the wheels (probably only available in Australia, but I’m sure motorcar paint shops anywhere would have a similar product) – it’s a marvellous very thin and very effective metal primer: it sticks to anything, in my experience even glass or granite benchtops! Therein lies a separate story, as you might imagine ….

Finally, a “dirty black’ initial topcoat. My engine is going to have a realistic (I hope) weathered appearance.

So there you are.

David

It’s beginning to look a bit more like an 8F (admittedly I have placed the pony truck in place and the smokebox door just for this picture, though).

A question however: when I started this project, I saw the picture of a lovely model 8F in brass-and-whitemetal finish. I was looking forward to the day when mine might look similar – but how can that be done if I am also going to have to paint parts of it before I complete construction?
I guess it doesn’t matter really, but if I am to have a realistic painted finish in places like the frames behind the driving wheels, surely this will have to be done by taking the wheels off.  Especially if I wish to have a good finish on parts like the springs, which are right behind the wheels, of course. As you’ll observe from the above picture, I haven’t put the braking gear in place yet. Once I have done that the wheels will be very difficult to take off. At present the wheels can be removed easily, because the excellent design of the MOK kit allows the motion bracket, valve gear and wheels to be removed as a unit.

So, how do other modellers manage it?
How do you make a whole brass-and-whitemetal kit up, and later get a good finish on it, without giving yourself a huge amount of unnecessary work dismantling all the careful modelling done to put it together in the first place?

Answer (I think): you cannot.  On the ‘net are articles describing how people have made up a model completely, then have to spend lots of effort systematically pulling them apart so that they can then be painted!  When it comes down to doing that, I do not think pictures of the unpainted model are so important, so I will paint the frames behind the wheels at this stage (and probably most of the stuff in-between the frames also).

First stage, take the wheels and the motion off the frames.  Fortunately this doesn’t prove too difficult.

This will also give the advantage that I can put the balance weights on the wheels whilst they are flat on the desk, rather than mounted on the frames.

The frames themselves will be easy to paint I hope, although I will have to mask off the sliding hornblocks (bearings) for the driving wheels, and avoid painting the compensation mechanism on the insides of the frames.

The balance weights will have to be chosen.  I hadn’t realised, but there are many variable configurations of balance weights between difference individual locomotive which are otherwise indistinguishable.  So I will need to find a picture of a locomotive in the area where I want to model (not too important) with a rivetted tender (which I think looks nicer), and then try to match the available parts from my kit to make the appropriate balance weights on my locomotive.  So, where do I find a side-on view of a Stanier 8F, pulling a tender with lots of rivets on the side, on the Settle-Carlisle Railway (or, at a pinch, anywhere in Lancashire or the North-West?

The 8F is progressing well, and I have been able to fit the special parts and run the assembled chassis for the first time!

It was a great moment to see it move for the first time.  After I cleaned my test track, it ran for the first time with almost no hesitation.

I decided to try running it with the connecting rods in place but before I try the return cranks, etc.  I had to wait to try out the running until the tender pickups were done.

The third picture shows the tender pickups: the compensation mechanism is still able to work (I have left loops in the wires to allow this, but there’s still a lot of gear to go into those spaces, so I’m not sure how well this will work) and the temporary connections visible going to the loco. chassis on the right. The split axles can be seen.

It doesn’t look much like an 8F, and the motion isn’t all connected yet but it shows that the tender pickups are working and that the assembly so far is acceptable.

It runs better forwards than reverse at the moment, but goes reasonably smoothly at 7V drawing 100-200 mA, and it’s still running without any lubrication.