Model Engine Works: M.E.W. Island Lighthouse

A lighthouse may seem a relatively easy building to make but to get the cone shape right is deceptively tricky since the proportions of the column have to look correct.
Also, forming a glazed housing for the lamp lens with a suitably shaped roof and balcony around it can be a difficult task to pull together. To this end, I had the idea of fashioning a set of parts that could be used to make many different shapes and sizes of the lighthouse.

For my prototype samples, I made a short cone and medium sized cone-shaped tower with which we all associate a lighthouse. I also did a building-style lighthouse with a cylinder shaped tower structure attached, as a comparison to the others. The main materials used in the construction of these buildings was 2mm, foam board, for the base, straight walls and flat shaped formers where required, thin flexible cardboard for anything that needed to be curved, and 50mm wide brown gum paper tape to reinforce the structure (not the reinforced packing type but the smooth art and framing tape). The glazing was a combination of recycled clear acetate and 30mm diameter clear acrylic tubing. I tried both on the lamp lens housing and found the acrylic tubing the best. Doors and windows I obtained from a set of Wills building accessory parts.

The basic cone shape is easiest to form as a flat shape on paper round a skeleton former. This is then reinforced with further layers of paper or gum paper tape which although relativity thin is very strong, and when slotted into the base and balcony is a very robust structure. I have shown a link to a document describing how I formed the cone shape. These can be made to any height that you may think suitable for your particular model. Of course, you can work with a straight cylinder if you wish although this will not fit into the slot in the base. If so a card ring can be cut and added to the bottom of this to do the same job. This is also the case if you wish to make a building with the light fitted to the roof.

The plinth is a cylinder which I have formed with a round disc made to the inner rim diameter of the printed base. I found that 2 or 3mm foam board was a good material to form this in as it is easy to cut for this disc. Two or three layers should be bonded together create a solid base, then thin card cut into a strip 15 to 25 mm high will form the wall. This should be overlapped three or four times to give strength and thickness. It is then possible to add an inner core of a height suitable to hold the LED just under the lens tube. I have found that this gives the best lighting effect with the lens.

The lens tube is a clear “Bic” pen outer casing that is cut to a length of between 40mm and 60mm. The top 20mm is grooved with a small round file forming between 4 and 6 equal rings in the top 20mm section. I found that turning the tube in a drill chuck made this much easier to do. I have allowed clearance in the balcony floor hole to wrap the middle section of this tube in gum paper tape which allows the forming of a stop at the bottom to position the lens at the correct height.

Forming the Lamp housing is done using a short section of 30mm diameter x 2mm wall clear acrylic tube. The height of this is not fixed and can be to suit your particular model. I would suggest that the lower section is covered in paper gum tape or similar material to stop light bleeding, which also gives a good line to form the windowsill ring around the top of this. This windowsill ring needs to be the same thickness as the proposed vertical glazing bars( I made my version 2mm height x 1mm deep).
The glazing bars can be made in many different ways. For my prototype models, I used 8 vertical bars 1mm x 1mm white plasticard bonded with super glue. It just needs an overlay fitting to the upper part of the outer clear acrylic cylinder which will give the impression of glazing bars. This could be as I have done vertical glazing bars or diamond pattern bars, offset glazing bars were also used in some lighthouses to allow for flat glazing panels.
To guide the installation of these glazing bars, I made a small cylinder of paper to fit inside the acrylic tube and marked the 8 vertical lines equally spaced on this.
I also used a paper ring to form the inner finish of the lower lens housing which is much easier than painting the inside of the tube and gives a nice crisp line at the top.

Doors and windows
I used doors from a Wills set of parts, and also windows and outer frames on the lighthouse building prototype. The openings in towers are formed with just a cutout and some acetate sheet bonded straight to the inner wall surface. The cutouts in the paper for both doors and windows have the edges sealed with PVA before painting.

The printed parts are a roof, balcony, and base ring.

The roof is an eight segment metal clad dome with a ball finial cap. The cap itself has a pilot hole for the addition of a weather vane or lighting conductor to be added. Under the roof, a rim is formed to accept a 30mm diameter clear acrylic tube which forms the lamp housing.
A balcony with railings around the outer edge has a trough formed in the top surface to take the bottom of the 30mm diameter clear acrylic tube. It also has a slot to take the cone formed at the base, with corbels on the outside of the cone for supports to the balcony.
The base ring is designed to allow the cone to sit within a rim in the top surface, and the bottom has a rebate around the outer edge to locate it onto the separate plinth. This plinth is useful to allow the removal of the structure when in place on a layout or diorama making it easier for the permanent fitting of an LED lighthouse lamp fitting.

Painting and finishing sprayed the printed parts and paper parts with a grey primer and then applied the render or paint finishes.
To achieve a render finish on the main tower I have come up with a mix of one part acrylic white paint, one part white powder filler and one part PVA glue, with a spot of washing up liquid to break the surface tension of the PVA. When mixed together a small amount of water is needed to create a smooth paste like texture, this is then stippled in place with a stiff brush. Once dry it can be over-coated with acrylic paints and then weathered.
Weathering was achieved with a mix of acrylic colours yellow ocher, sap green, Payne’s grey, and white. These were applied in thin washes and by dry brushing There is also a rust wash and staining in areas around the railings and balcony, which was done with enamels thinned and dry-brushed.

Lighting unit
The lighthouse simulated rotating lamp effect unit by Mini Lights can be purchased in several different versions and they give a very realistic flash to a static light source. My first sample unit was mounted on a plinth that raised it up into the core of the cone to just under the lens tube. I found it focused the light better by adding a small upstand around the lamp. It is much easier to have the base for the lighthouse separate, so this can be added to the landscape and wired in without risking damage to the lighthouse model itself.

The power for my unit was from a 9V battery. I mounted this in a switched battery box, these are quite freely available on the internet. The units are rated to run on a 7- 13 volts regulated DC power supply or 9 volts battery. To further aid the changing of the battery I added a pair of low voltage plug connectors between the light unit and the battery box.

List of suppliers:

Mini Lights Lighthouse simulated rotating lamp effect unit by
https://www.mini-lights.co.uk/mlshop/lighthouse-lighting-effect-unit.html

4D Model shop London 30 mm dia Clear acrylic round tube 330mm
https://modelshop.co.uk/Shop/Item/Clear-acrylic-round-tube-330mm/ITM2040

Any good art shop supplier.
Gummed Paper Brown Paper Tape Picture Framing Canvas / Gum Wet 200m x 50mm roll
(note not the reinforced packing tape).

3D Printed Parts
Model Engine Works on Shapeways
https://www.shapeways.com/shops/model-engine-works

Cone pattern development document.
https://drive.google.com/file/d/155N8zx6Zl3zm1o4C4EalgVkWx7qNqEor/view?usp=sharing

Monday, 3 January 2022

M.E.W. Island Lighthouse

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