Saturday 19 April 2014

Thornycroft Buildings - Review

The 15 factory buildings (and a railway bridge) presented in previous posts were scratch built in hobby time over about 5 months. All are based on documentary evidence of the Basingstoke factory and an invaluable contribution from a past employee.

Some aspects may be incorrect so, if any other Thornycroft veteran or academic would like to proffer their knowledge then I welcome it as I have no qualms about remaking buildings or correcting background information presented in postings.

There are three distinct phases to our Thornycroft Sidings project. The first was creation of the buildings; the second is the baseboard with scenery and working railway and the third is populating the layout with people, vehicles and factory materials. I expect all this to take well into next year.

With the buildings complete it is time to build the baseboard to accommodate them and this will surely be the subject of the next postings.

But, before moving on let's reflect on 'phase 1'. Faced with recreating the factory buildings (actually about a third of the real factory) sounds a daunting task but elements of it have helped to spur me on.

First, is the historical research undertaken because each piece of information or photograph uncovered increases knowledge in all manner of things from architectural details in building construction to the 'pickling' process of metal castings.

Second, is the variety of buildings on the factory site that make modelling challenging, from ornate brick to functional corrugated iron, from a model no bigger than half a thumb to one nearly half a metre long!

Third, is experimenting with different modelling techniques during construction. The most significant of which was window fabrication. No less than five different methods were tried, which I would like to review for you here.

At the outset I assumed that to model the actual buildings the windows would need to be scratch built rather than using proprietary parts so, brass frets or injection moulded plastic, which I know can have the finest level of detail were not used.

1. Opaque Printed

Designed in a graphic editing program to a resolution of 600 pixels per inch and printed on ink jet printer. The opaque window glass is a photo of  a real glass pane. For windows It is dark grey with white overtones giving the appearance of light reflection. For roof skylights, white to very light blue.

Good Points
Any style can be created with very fine glazing bars. Repeatable elements are produced quickly with consistent dimensions.

Questionable Points
Two dimensional, no relief although shading effects may compensate for this. Need a computer, printer and have access to and be competent in use of a graphic design application. No good if interior views or interior lighting is wanted.

2. Transparent Printed 1

As  above but printed on transparent film.

Good Points
Transparent like real windows so interior decoration or lighting can be seen.

Questionable Points
Limited colour palette for glazing bars using conventional home printers. White is not a printable colour and rainbow colours tend to be washed out. Black is commonly used but how often do we see black glazing bars? Possibly OK  for leaded panes. In the photo the glazing bars were printed this way but the frames are white card stuck on the film.

3 Transparent Printed 2


As 1. above but printed on a sticky label sheet that is then stuck to transparent film. The window panes are next sliced out to reveal transparency using this technique.

Good Points
Very fine glazing bars are achievable with good eyesight, a steady hand and sharp scalpel. I found the exercise quite therapeutic. Realistic glazing bars in relief. Could be done without a computer using sharp pencil and rule for design.

Questionable PointsSome may find it too repetitive or tedious. Quite easy to break and peel off bars, for which very thin strips of sticky paper have to be cut and fitted to repair it.

4. Sticky Label Strips

Fit transparent film to the window opening. Cut a long thin strip from white sticky label sheet and cut to length for each side of the frame. Stick to window. Cut another long strip thinner than the frame and cut to length for each glazing bar. Stick in place on window. This technique was used for the roof skylights in photo.

Tip: Lightly rub a pencil over the paper before cutting out for a weathering effect.

Good Points
Quick, using conventional modelling tools of scalpel and metal rule.

Questionable PointsNeed to accurately mark up the paper to get consistent dimension, which is a manual task prone to error. Manually fitting the strips may also lead to inconsistency.  Overlapping strips whilst quickest may be unsightly.

5. 3D Printed Plastic

So, you don't have a 3D printer? Shame on you! When you do get one you'll also need to obtain and learn to use a CAD Application so you can design the windows. The side wall windows in the above photo are 3D printed and stuck to transparent film for the glass.

Good Points
Create elaborate designs with built in relief. Can batch produce at the touch of a button.

Questionable PointsHelps to be a mechanical CAD designer. Design and print can take a long time but small, simple objects like window frames are quick to design and print out in batches. Printer may not be capable of very thin N scale details. Smallest width on our machine is 0.5mm (3 inch glazing bars in 2mm scale!).

In conclusion

Not one of those methods stands out as a best approach for realism or simplicity. They each have their own  merits and downfalls. Best thing to do is choose a method that suits your own needs and abilities. If I had to choose a method for 'N' gauge I would lean towards the first method, assuming it's a bespoke design and transparency is not required.

David


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