It’s been some time since I last tackled an etched brass kit, after spending most of my time recently in learning about 3D printing and, before that, Silhouette cutting. I had to refresh my memory on ‘the rules of the game’!
I bought the Broad Gauge Society kit (FL07) for a 6-wheel tender some time ago and have only just got around to its assembly. I was pleased to see that the instructions start with the reminder that “… some parts are a little over scale due to limitations of the design and etching process. You will need to trim some parts to fit.” I’ve fallen foul of this in past and had to open up some holes after folding parts, which was awkward to do. Of course, the ‘experts’ know all about these things but it’s still good to be reminded.
Fig 1 Broad Gauge Tender Side
Unfortunately, though, the instructions seem to contain more information about what not to do than actually providing instructions on the order of the build. I feel that one of the main reasons for buying a kit is to know that someone else has done the hard work of determining exactly how to assemble the parts in a rational order and will lead you through, step by step.
This kit also appears to have been photo-reduced from a 7mm scale kit, as the embossed rivet detail is too small to press through the relatively thick brass sheet. I decided to ‘cheat’ and use the floor upside-down so that the fine embossed detail shows on the upper side. It’ll be hidden under the coal anyway and is virtually invisible in 4mm scale.
So, to begin at the beginning… “Fold the tank sub-assembly (47) and offer to the floor. Check that all is square. Do not solder the sides to the floor at this stage” I assumed that it was OK to solder the other tabs to the floor because this was the only way to hold the box shape but, later, I began to wonder if this is what was actually meant.
Fig 2 Water Tank Construction
Then, we hit one of those deceptively simple-seeming instructions: “roll up the tank filler (20)”. Well, I’ve rolled several boilers and found it easier than predicted but, in this case, the tank filler is a tiny rectangle of brass, about 15mm x 4mm and not easy to handle, even under my illuminated magnifier. After some thought, I wrapped it around a 5mm drill shank and then teased it, with difficulty into the hole in the tank top. How to fix it? Well, there are no tabs or lugs and my tank was now a closed box with no internal access.
Fig 3 Tank Filler
Now the instructions start to lose their way. It inspires no confidence to read “The filler lid probably should have been one piece, the hinge being under the lip rather than as depicted. Solder the overlay to the top of the tank with the filler as a location aid.”
The overlay is a large, nicely detailed sheet with no lugs or other alignment aids. The hole does have to align with the filler but how should it be soldered? There are no suggestions and, at this point, the notes seem to cease being instructions at all. The next paragraph starts “The tender, like most, has a flare.” It continues “There are thus three difficulties ...” Not very encouraging! There are then suggestions to “Back the corner on the inside with some paper-thin shim and fill it with solder.” There’s no mention of any part numbers or what is meant by ‘paper-thin shim’ and then at the end of the paragraph, we read “Some careful fitting will be required as these parts are over size.”
Time to stop and think!
Perhaps, the overlays could have been soldered, if the main tank component had not been folded in the first place but, instead, put on a hotplate, tinned overall, and the overlays slid into place (how?), then allowed to cool. The tank filler could then have been soldered from the back and so on …
My own solution, however, was to abandon soldering at this point and to use glue to attach the overlays onto the already-formed tank assembly. This allowed the edges to be aligned carefully, using fingers
Fig 4 Top overlay glued in place
The folded overlay to form the coal space has no indications of where to make the folds, so trial and error was needed, to achieve a close fit into the curved recess. Fortunately, the brass is thin and flexible, so fingers were sufficient to make the shaping. I assembled an ad hoc collection of clamps to hold this overlay in place while the glue hardened.
Back to the instructions “Next fit the rear plate (51), ensuring it is centred before soldering but do not solder the wrap-around ends to the sides as the side plates need to be tucked under the ends. Next form the front pieces so that the handrail holes are just on the flat sides. Finally add the side pieces, two parts to each (61), (62), (64), (65). These will need trimming so that they are equal in length when fitted.”
I chose to glue the rear plate in position, using the notches in the curved top to set the centre of the curves to the sides. In order to make the flare along the top, I again used drill shanks as mandrels, using different diameters to hand-work the top edge to the required shape.
Fig 5 Making the Top Flare
I again used clamps to hold the overlay in place until the glue hardened. The ‘front pieces’, which are described as “(52,53) Tank, front plating” on the parts list, looked as though they would be very tricky, since they curve round the forward spurs from the tank and have very little area on which to be fixed to the outside. There is also the warning that “these parts are oversize”. Since there are two further pieces to complete the overlays along the sides, I could see that matching up all these separate sections was not going to be easy.
I decided to turn back to soldering for these parts and, having measured the correct overall length, I laid the parts out along the sticky strip of a ‘Post-It’ note, to hold them in position while I applied a very thin skim of solder along each joint from the back side. This gave me a single component that I could glue into position and subsequently fold to fit around the front end. Rather to my surprise, the first attempt worked quite well.
Fig 6 Soldering the Side Overlays from the back
This method of construction produced a robust overlay that withstood the folding that is necessary around the front end of the tank.
After completing the first side, the second went together much more easily and quickly and, hence, the main upper body of the tender is now completed.
I now feel in need of a break and a glass of wine. The next post will be about the chassis, so we shall soon find out how well that fits together – there seem to be rather a lot of very small parts