Tubelights

Light under the Boulroie platform shelters ...

Single-tube lights but there are doubles, too

This was published in Modelspoormagazine 62 - more pictures and text can be found there...

This method to make miniature tubelights was developed after the dual-tubelights method. These lights aren't bad models, but a little to big for some applications. If you don't mind doing some work in advance, these smaller single-tube versions are even easier to construct.

The construction concept is the same: tiny SMD-leds shine their light at alight conducting material, which seems to produce light by itself, but in fact diperses the light. With this method, I used the smaller 1206 SMD’s, measuring a meagre 3,2x1,6x1,2mm.
These SMD's, soldered together and wired, are cast inside a transparent resin using a mould. This means we need a few master models. Each cast model will have the form of a complete tubelight set.
A too complicated short description? Then take a look at the next commented pictures:

The two broader strips are glued together to form a square 1,5x1,5mm profile. On top of the glue line, we attach the smaller 0,5x1mm strip. This smaller strip will smlulate the lamp form.

This upper strip is shaped to a tublight form using sanding paper. A sharp knife is used to scrape the tube light's support shape.

This way, we have ourselves a very long tubelight casing. This shape iscut in 6,5mm lengths. We now have more pieces then needed, but this way we can select the best resembling shapes.

These chosen shapes are glued to a piec of styrene sheet, and a mould is cast from it. As the soldered SMD's will be placed in the lamps base, I made small cuts in the mould, so I can hang them by their wires in the setting resin.

To solder the SMD's nicely in one line, I made a small tool. A piece of heat-resistant is milled, so a 1,6mm wide and 1,2mm deep gap is formed. In this gap, the SMDs have a tight fit.

Don't apply to much heat to long while soldering so close to the Led's chip. While they're still in their placeholder, I soldered the thin connecting wires, too. After this soldering, the SMD's are tested using a resistor and a power source.

We now use the transparent resin. As this has a longer setting time than common resin, we have enough time to work. We need very little of the mixed product, as each mould opening only needs a drop. Using a small piece of scrap styrene, this drop is spread into the mould.

The prepared SMD chains can now be put in place, the light emitting sides facing down. The cuts we made earlier hold the connecting wires. Once all the leds are placed right, we can scrape of any leftover resin. The resin takes about 3 days to set completely.

After cleaning the cast forms, they're put upside down in a piece of silicon rubber, in which we made some light cuts. The lamp's housing can now be airbrushed while the imitated tubelight is protected from paint. We use a silver paint first, so the inside of the shape will reflect and disperse the SMD's light.

A following black layer seals off any light from the lamp's housing, so only the tube imaitation will "shine". To see where lights leaks through, apply enough current. A final layer of white paint, including the tube, is applied. The lamp set is now ready for the layout.

Double-tube lights

This has been published in Modelspoormagazine 58 (april 2007) - more information and pictures can be found in that issue.

Construction drawing using 2 PLCC-2 leds.

These SMD-leds are sold in a special strip.

Old diskettes can still be useful. They have just the right dimension for a soldering jig

Soldering is done using a tinning fluid and electronics solder. Filing of the connection gives a smooth surface.

We use lacque wire, as used in solenoids

Mark one wire, as the polarity of the leds has to be recognized afterwards

The casing is made of thin styrene sheet. First the bottom, next the two side panels

They are cut to the right dimension after the glue has set

The wire needs an opening in the case. From a piece of brass rectangular tubing we make a shizel

With this little tool it's easy to cut out a tiny rectangle out of a small peace of sheet styrene

These parts are then cut and sanded to shape

... and glued to the ends of the casing.

Now we have a cradle-shaped armature fot our tubelights. It just needs some fine cutting and sanding to get a smooth surface.

No light can shine through the housing, so it is painted black

Transparent heat-shrinking tube and thick fiber are the materials we use for the actual tubes.

Two pieces of fiber are shifted in a piece of shrinking tube, which is then heated. This way we get an oval sectional shape

This is cut to length and glued on top of the leds.

The result: a tubeline armature were the tubes seem to light up themselves.

Mounted under a station platform ...

Using the correct resistor (some experimenting is useful) - we have a very fine result.