Ratio SR Concrete lamp posts - Conversion to LED

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Brian
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Ratio SR Concrete lamp posts - Conversion to LED

#1

Post by Brian »

Barry Clayton AKA bulleidboy has given me permission to post his method of converting the Ratio 454 SR lamps to lit versions. I thank Barry for allowing this to be published here. I have slightly amended the article to bring it more in line with today's prices and supply and any comments I make has been added in Blue.

Ratio SR Concrete Lamp Posts - Operational.
I have seen many layouts, both at exhibitions and in the modelling press with these lamps – they would look so much better if they were operational – now they can be.
The Southern Railway produced their concrete at Exmouth Junction Concrete Works from the 1920’s to the 1950s. They made concrete bridges, concrete platform fences, concrete sleepers, and concrete lamp posts.
You will require:
A pack of Ratio 454 SR Concrete Platform Lamps – this makes four double lamps.
A 4mm woodboring drill bit this has flat cutting edge, but with a sharp point in the middle. Like this example link to example
A 0.5mm drill bit.
A pack (20?) 0402 pre-wired micro SMD LED’s – Bulb size 1mm x 0.5mm – Choose Warm white. These are available from eBay or Chinese suppliers such as AliExpress. Note my 50 pre wired LEDS were £4.55 plus P & P from AliExpress

This is not a difficult job but does requires a degree of patience.
Start by drilling out the lamp shade, I used a Bosch drill/driver with variable speed. I had a piece of 12mm plywood in which I drilled a small (2-3mm) hole, in which I placed the lampshade and held it in place with a pair of pliers while I drilled. The shades do have a central “dimple” which does help in placing the “point” of the 4mm drill bit – with the drill turning slowly, you will see white shards of plastic curl up. The hole does not need to be deep – 2mm max. With this job done, you should have a shade which now looks like a proper lamp shade rather than a blob of white plastic. As the drill had a fine sharp point, it left a small “dimple” in the bottom of the hole you have just drilled. Using that as a guide, use the 0.5mm drill bit, drill up through to the top of the lamp. I found this was a little “hit and miss” – sometimes the hole was perfectly central, another time the drill bit came out through the side – this does not matter too much as the wires from the LED are so fine a dab of paint will hide the hole. Another way of improving the centralisation of this small hole is to place a tube (metal tube – brass?) that is just long enough to cover the top of the shade, it needs to be a tight fit - and drill down from the top – if nothing else, it helps keep the plastic together when drilling.
Thread the wires (two) up through the lamp shade and secure with a dab of glue – I have used all types (Superglue, PVA, Liquid Poly)– it just needs to hold the bulb in place at the bottom of the 4mm wide hole you drilled.
Now attach the lamp shade to the lamp post. I used a minute spot of Superglue. Try to position the shade so that the wires can be glued along the arm of the post. Carefully glue the wires along the arm as far as the central post. When this is dry, – if you look very carefully you will see the very slightest indentation running down the length of the post – using a set of needles file it is possible to slightly enlarge that indentation, then running a bead of glue down the indentation the wires can be attached to the main post. If making a “double lamp post, I found it better to run each pair of two wires down either side of the main post – try to keep the wires taught while the glue sets. I also brushed a little superglue at the very bottom of the lamp post to hold the wires in place – it is easy to pull the wires off the lamp post with some glues.
The shades in real-life (see Corfe Castle Station) are opaque glass – so no need to paint, but you should paint the bulb-holder(?) – I painted mine SR Chrome Green (Precision Paints), in later years this part of the lamp was black.
Hopefully, you will now have a finished lamp – a couple of coats of Railmatch Concrete paint will hide the wires running along the arms and down the post.
The LEDs operate from a 3v DC supply. With a series resistor of around 1K (1000 Ohms) they can run safely from a 12 volt DC supply. Use a higher OHM value to reduce their brightness as needed. I run the power supply through a variable voltage regulator (dimmer switch??) – from ebay.
The cost worked out at about £1.50 per lamp.

Thank you Barry an excellent set of instructions. :D
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Tricky Dicky
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Re: Ratio SR Concrete lamp posts - Conversion to LED

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Post by Tricky Dicky »

Surely you mean a 0.5mm drill, 0.05 is the diameter of a human hair!

Richard
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Brian
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Re: Ratio SR Concrete lamp posts - Conversion to LED

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Post by Brian »

Correct and text amended. Thanks for spotting the error which was in the original text!
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Steve M
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Re: Ratio SR Concrete lamp posts - Conversion to LED

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Post by Steve M »

Tricky Dicky wrote: Fri Apr 26, 2024 2:52 pm Surely you mean a 0.5mm drill, 0.05 is the diameter of a human hair!

Richard
Yes, but it does make for a very neat installation. ;)
"Not very stable, but incredibly versatile." ;)
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bulleidboy
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Re: Ratio SR Concrete lamp posts - Conversion to LED

#5

Post by bulleidboy »

The finished product:
ImageIMG_0882 by Barry Clayton, on Flickr
I made a huge to do list for today. I just can't figure out who's going to do it! :lol:
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