Here's where I've got to. Something emerging from the chaos on the workbench. Looking a bit Barry scrap line in this state.
The tender body presented a few challenges. For the most part the sheet metal goes together with commendable accuracy. The front section of the fire iron tunnel is a bit of a curse, having to bend on two lines to match the tunnel profile and the front bulkhead. Putting the main assembly of end & sides, front & rear bulkheads, rear deck and the main coal space profiles took some doing, not because they don't fit nicely together, but this is one instance where all the slots and tabs fight each other, some being at mutually antagonistic angles! Eventually the last tab is manipulated into its slot with a click and the whole structure relaxes into position. Soldering up was all done from the inside and reasonably straightforward. I didn't bother soldering all the seams because the fit is good, and most of it will be hidden under a few scale tons of late sixties slack.
The tender overlays were next - and a whole load of trouble. I've never got on well with overlays, and these ones scared me! The kit, rather generously, provides side and rear overlays for both the riveted and the welded 4,000 gallon tender. The riveted overlays look rather splendid, but 48142 had a welded tender, fortunately as it turned out. I found forming the overlays to match the curves previously made on the tender body to be really difficult. I figured it would be easier if the overlays were annealed, so I experimented on a riveted side overlay first. I'd wondered if heating the overlay to anneal it would cause it to pringle up, but mercifully it stayed flat. I formed the curves using the same approach as described for the body, but as the overlay bends more easily you have to take it carefully to avoid kinks. That's the downside of annealing. I got reasonably close to the right shape, but accepted that I'd have to use clips to hold the edges down when I soldered them in place. I started by fitting the rear overlay because that's easy to do, and it dictates the longitudinal position of the side overlays.
You'll have noticed in previous photos that the main body etches have a load of small rectangular holes in them for soldering on the overlay from the inside. With the main body assembled the holes higher up the tender sides, just below the curve, are virtually inaccessible by soldering iron, or RSU probe for that matter. My first attempt was to mark the positions of the holes on the overlay and pre-tin round them on the tender body. I used 145 degree solder for this to reduce the heat input, not that it made much difference in the end!
The overlay was clipped in position, adjusted to match the rear overlay, tack soldered at the rear, and then the 40W iron was applied to the outside of the overlay at the marked positions. In most positions the overlay expanded up where it was heated and needed some pressure with a lollipop stick to keep it in contact with the body. The result wasn't great...
You can see there are dimples all over in this cruel photo, where the marker pen's not rubbed off. Some prototype welded tenders do show ripples in the side plating, either from welding distortion during manufacture, or from use & abuse over the years. Some welded tenders however appear to have very flat sides. The ripples show up more on a clean, shiny tender than they do under a coat of matt BR grey. This 8F will be appropriately filthy, even so, there will need to be some filling & sanding on this side before painting. Think how much of a pain that would have been with a riveted overlay!
I had a rethink, and tackled the other side differently. The overlay was positioned and tacked at the rear, as before. The overlay was soldered from the outside in the uppermost hole positions below the curve, simply because there's no access from the inside. This time I chose to use the RSU instead of the iron. Seemed to get on better, but there are still small dimples discernible but they'll disappear under a rear of filler and some primer. This time most of the soldering was done from the inside. A blob of flux and a small chip of 145 solder was put into each hole. The RSU probe was applied to the main body etch alongside the hole until the solder melted and flashed into the joint. The advantage is that the overlay is held against the flat underlying surface by the RSU probe and body etch, and the probe can be held there until the solder's frozen. That worked out much better, very little distortion, and was probably closer to how Mr MOK had intended it to be done.
All around the edges of the body, where the overlay edges sit over the main body edges, I built up a decent bead of solder and then filed it back to produce a clean edge, free from cusp marks or divots. Time consuming, messy and it clogs up your files, but makes for a tidy job. The edge is slightly thicker than prototype, and the edge beading etched on the overlay isn't half round, but it's not practical to do it any other way with the kit. I've convinced myself that it'll be OK.
There are some things to note about building the welded tender from the MOK kit. There are some etched rivets that should be removed, and some riveted detail that doesn't need to be added. Considering how many welded tenders the were, it's been hard to find good detail photos of some areas to establish where they did and didn't have rivets. The GA drawing for the welded body suggests that everything was welded, although the drawing doesn't use any clear convention for showing weld detail, so it's a bit fuzzy. Photos suggest that welded tenders did still have some rivets. Some details, starting at the front...
There are rivet overlay strips provided to go around the coal space door and the locker. You don't need these on a welded tender. The lifting point doubler plates in the front bulkhead have etched dimples, but really need to be drilled through and have 0.6mm wire soldered in to represent rivets. The Front and rear bulkheads were topped off with a substantial half elliptical beading section, and photos show that was riveted, even on welded tenders. Possibly the riveter's union was pushing back against the rising tide of welding, who knows? So don't remove the rivets around the top curve of the F & R bulkheads. There are some etched parts (part 138) in the kit that I think are meant to be the bulkhead beading, but they're too wide and too thin. I cut some strips 1.4mm wide from some 0.6mm NS scrap, soldered then in position, and rounded them off to a vaguely elliptical profile with a file and wet & dry. They look the part. Also worth mentioning that the lamp guard is referred to as a step in the (David Coulshed) instructions, but it's actually a guard to stop lumps of coal falling onto a lamp stowed on the bracket below. If you thought it was a step you'd probably fit it the wrong way up!|
On the coal space side of the front bulkhead remove all of the etched rivets, but do apply the curved rivet strip to the top of the bulkhead.
The rear bulkhead keeps it's rivets and has a bead profile added, as per front bulkhead. There's an additional thin plate on the rear of the bulkhead shown on the GA drawing, and visible in photos. It's not very thick on the prototype, so I made a plate from some brass shim. Interestingly the GA drawing shows some stiffening angle sections between the tender side and the rear bulkhead, but they're not visible on any photos that I can find, and that'a good enough excuse to leave them off! On welded tenders the water scoop dome and the filler neck were simply welded to the rear deck plate, so there's no need to use the etched riveted flanges provided in the kit. The vents were still bolted to the deck, so don't go filing off the bolt heads! Where angle brackets were provided to fix the tender tank to the chassis, they were welded to the tank, so there's no need to add the etched rivet overlay parts here. In the photo it looks like I've added them, but that's just the reflection of the rivets on the tender floor!
Here's the best photo I could find of the rear deck of the 4,000 gallon welded tender on sister engine 48141 (from 'The Book of the Stanier 8Fs - Part 2 Wartime Engines 48126-48297', Irwell Press, and the photo's credited to Rail Online, so probably a Jim Carter snap). Another tiny detail - the the lifting lugs are squared off on this tender, but rounded on others. The GA drawings show rounded lugs, and the kit provides rounded lugs, so that's what 48142 has got! Oh yes, I've just realised that the tiny lug for the filler lid chain is missing from my dome, always another thing to do...
Next job is fitting the body to the floor, and a sprint to the finish on the remaining tender detail. I can see light at the end of the tunnel.
