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The Methods Described

Making typically British Victorian Station & Yard Lamps.

Up until the early half of the 20th Century, most stations were lit by oil or gas lamps. There were a few early examples of stations lit by electric arc lamps but these were in larger towns and cities which would have had a "municipal electricity works".

In rural locations, the lamps would have been oil burners, since gas supplies would have been limited to areas around towns which had a gasworks. I can remember, as late as the 1970's, as a commuter on the Hastings line, there still being oil lamps at both Frant and Stonegate stations while all the trains were diesel powered.

There were two principal "styles" of lamp. The smaller would have a four-facet arrangement, while larger lamps (often containing double or triple burners) would be hexagonal. The same style of lamp could be found mounted on a post, on a wall bracket or suspended from the framework of a canopy.

Platform lamps were usually of the smaller type and mounted at a height of around 8ft or so. Yard lamps tended to be of the larger type and mounted on much taller posts (typically around 15ft) to cast light over a wider area.

Now to the task of producing such lamps at home.

Posts can be easily made up from varying diameters of plastic and brass tube (telescope style) and decorated with as little or as much frippery as you wish.

First the lanterns themselves need to be produced and this method employs two very different materials to cast the two components. The two casting resins are very different in nature but the same silicone rubber can be used for the moulds. The "glass" section of the lantern will be in solid "water clear" polyester resin (horrible, smelly stuff, which stinks of styrene and can take many days to fully cure) and the "bonnet" which sits on top and is of , comparatively, easy to use polyurethane resin.

However, before anything can be cast, you need a pattern and a mould.

The patterns and moulds for the lanterns and their respective "bonnets" are shown below.

Below are the initial test items cast (in polyurethane) from the lantern mould, to check integrity before proceeding with the clear resin casting. These test items were used as extra patterns to produce more moulds, since you will want to cast several clear resin components at one session (you will understand why later).

Below are the bonnets cast in polyurethane, glued to the clear lantern and painted (in GWR colours). Note how the hexagonal lamp produces internal reflections owing to the angles of the panes(this is not so prevalent in the four-faceted types).

The patterns were produced from plastic card and "filler" with a bit of basic geometry thrown in. To spare you the calculations, the dimensions of the main components which make up the lantern patterns are below.

When you have cut the panes, assemble on a base of plastic card, larger than the lantern, attaching by what will become the top of the lantern (do it the other way up and you won't be able to remove the pattern from the mould)! Ensure symmetry when carrying this out. Now enclose the top of the pattern, an insert of plastic card or a blob of Isopon will do the job. Next cut narrow strips of very thin plastic card and use to add to simulate the framework which holds the glazing. Use filler if necessary to tidy up the seams. You now form an open top box around the pattern and you are ready to make the mould.

You now have a mould for the lantern, next you need one for the "bonnet". This requires more plastic card cut to geometrical shapes plus some plastic tube for the "chimney". Below are dimensions to assist in shaping the bonnet. In the case of the large lantern, cut a circle for the base before marking out the points on the circumference with dividers and then cutting the hex shape.

As with the lanterns, assemble the components on a piece of plastic card larger than the bonnet base. When the segments have been glued to form the pyramidal shape, use filler to produce a neat finish. Now you will need to remove the apex, in order to fit a chimney. This is made from a selection of tube sizes and filler and can be as plain or decorative as you wish (but bear in mind that if too fragile, it will be impossible to remove from the mould without damage).

Observations on the use of "water clear" Polyester Resin

Both types of resin involved in this project are mixed by weight but the ratios of the two parts (resin and catalyst) are very different, as are the curing times and resulting properties.

Polyurethane resin is mixed in equal weights : If you want 100 gm then you add 50 of part B to 50 of part A and mix least one minute.

The clear polyester resin is very different : If you want 30 gm then you pour that weight of the styrene into a mixing bowl and add very little little as 3 percent by weight.

You will now understand my earlier comment about wanting several moulds. It is extremely difficult to measure such small quantities even with digital kitchen scales, which register only whole numbers, not fractions. It is very difficult to get the proportions correct (and to fully mix) with such small quantities and, without quite a few moulds to fill, you will waste far more resin than you use.

Whereas (subject to ambient temperature) a polyurethane casting can be removed from the mould in anything from 30 minutes to several hours, the polyester resin needs to be at around 20 Celsius before it is mixed and then can take up to a day before it can be safely removed from the mould and even then you should avoid touching the important surfaces, since it will leave finger marks. The polyester can take up to week or more before it fully cures and can be confidently handled. Another point to be aware of is that different brands of polyester have different requirements. Some insist that the "open" side of the mould is sealed from the air while others do not require this. The first brand I tried was Swiss and and I had two consecutive failures with it before switching to the current British brand (at around a fifth of the price). One point which I have observed is that the clear polyester has a shrinkage factor : It is very slight but if you fill a mould just to the brim, you will find it has dropped in level when hardened. I tend to fill mould so the surface tension raises it just above the brim. Polyurethane resin does not shrink so fill just to the brim.

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Page last modified on July 23, 2017, at 09:04 AM