Monday, 26 February 2007

Weighbridge office

The station building plans are coming on slowly, but I've decided that it would be slightly silly to attempt the largest and most complex building first. So I decided to start with something much smaller and more straightforward - the weighbridge office.

I've only found one photo of the weighbridge office at Llanfyllin and that's in a general view of the station and goods yard taken from (roughly) the goods yard entrance. From this angle you can only see the end profile of the building, so my model is definitely not an exact replica. Instead I've used my rough guesstimate of the overall proprotions and basic style from this photo, then built up the rest of the picture using photos of other similar structures.

I drew the plans using Adobe Illustrator, and you can take a look at them (somewhat reduced in scale) here:

The basic bodyshell was marked out on 40 thou Slater's plasticard (I was going to use 30 thou which is a lot easier to cut, but decided the 1mm thickness of 40 thou would make measuring and ligning everything up much easier, which I'm glad I did). I also marked out a second piece for each wall, 1mm narrower at each side and 1.5mm lower along the top, to add extra strength and to allow the four walls to lock together squarely. As well as the walls I makrked out a floor piece (again double thickness) and the chimney. I lightly score the outlines using a sharp knife with the aid of a small steel rule and engineer's square, afterwards rubbing some pencil over the score-marks with my fingers so they show up more easily.

With everything measured up and marked out I then set to work cutting each piece out. This is done with several light strokes of the knife along the steel rule edge (first locating the tip of the blade into the existing marks to ensure an accurate alignment. After several runs of the knife you can gently snap the pasticard, then clean up the edges with the knife.

The next stage is to cement the double-thickness walls and floor together using Slaters Mek-Pak. It pays to line each pair up first and check the measurements and make any necessary adjustments with a file or knife. Most of my pieces were a good fit fortunately.

Mek-Pak dries (or more accurately, evaporates) VERY quickly so I find I have to work very quickly with a loaded brush to ensure one entire surface is flooded before bringing the two pices together. A quick adjustment of the alignment is usually necessary, then the two pices can be pressed together firmly, and a little Mek-Pak touched to each of the joins, allowing it to run into the seams.

These then need to be left to dry for several hours, ideally under some heavy books to make sure there's no warping.

My next task was to cut out the embossed brick overlay for each wall. I've used Slater's '00' red Flemish Bond (this is the bond used on all the Llanfyllin buildings). The same method is used for marking out and cutting the brick sheet.

In order for the bricks to line up seamlessly at the corners I find it best to allow the brick layer to overhang the edges of the walls by about 1mm, then to file a 45 degree mitre along the edge so that when the two walls are joined together, the bricks meet at the corners. This takes some patience to get right. If you cut or file off too much you get a gap - so its always worth erring on the side of generosity and then gradually filing away until you get the right amount. Its best to actually do the filing once you've cemented the brick sheet to the wall, as you can then check the fit as you're going along rather than doing it all in once go and just hoping for the best!

Finally, for now at least, I joined all the walls and the floor together. The chimney is attached to the back wall and was constructed in one piece with it.

More to come soon.

No comments:

Post a Comment