Coughtrie Lamps Question.

[Lancs Lad]

I have one of these Coughtrie fittings (see pic)

I want to use it upside down as the centre-piece on a garden table.

Will it still be weather proof? Or will rain find it's way around the rubber collar, and collect inside?

I saw these lamps used, upside down, at the Minack Theatre in the 1980s, as 'house' lighting, and just wondered how successful they were at keeping the rain out.

Any thoughts?

[duncanlowe]

I don't know for sure. But will say, that it's quite likely that water will sit in the threads because of gravity, and changes in pressure caused by either barometric pressure or temperature (including temperature caused by the lamp inside) are quite likely to end up sucking that water in. If there's some kind of venting elsewhere probably less chance. But water has a really nasty habit of getting past seals when gravity is on it's side.

[Lancs Lad]

Thanks, duncanlowe!

That's what I was bothered about!

Water will get in wherever it can, won't it?

[duncanlowe]

Originally Posted by Lancs Lad

Thanks, duncanlowe!

That's what I was bothered about!

Water will get in wherever it can, won't it?

Absolutely it will. It will wick along cables and get into electronics if it can. Believe it or not I have even seen times where it can defy gravity and get into electronics just by 'sticking' as in surface tension allowing it to run uphill.

[Roger Ramjet]

Hi Peter, have you considered converting the fitting to SELV aka low voltage LED or similar. That way the lamp would not be a danger even if water did seep in.
Rog

[Lancs Lad]

That's a really good idea, Roger! Thank you so much.

It wouldn't be difficult to do, and, as you say, would be safer than 240 volts if water did find its way in.

Those upside-down Coughtrie lamps were there for years at the Minack Theatre in Cornwall! Mounted on conduit inside granite bollards alongside the steps down the cliff. They must have withstood many a Cornish winter, and kept working!

I wonder what happened to all those lovely fittings when they were replaced with the LED lights they now have?

I hope they weren't just thrown away. I'd be very sad to think that they were just discarded.

I've got a real soft spot for 1970s Coughtrie lights. They're very attractive, and so very well made. Nothing you can buy in the DIY shops these days comes anywhere near the quality of a Coughtrie.

[thermionic]

I remember those at the Minack Theatre!

They were all replaced during the mid nineties having done sterling service for many years in a tough environment.

I’m pretty sure that there was a 2 - 3mm evacuation hole drilled into the alloy near the threaded cable entry, and from memory there was evidence of water ingress but it has drained away so not causing any problems. I guess these were not designed to be mounted in this way, but they did last for many years.

I think you will be safe doing something similar.


Cheers.

SimonT.

[Lloyd 1985]

The one thing to watch on these lamps is that there is a tiny gap between the top dome shaped bit, and the bit the glass screws into, there isn’t a seal in there, just a metal lip. Depending on the age of the fitting, the top dome bit is either held on by the screws that also hold the bulb holder, or some sort of clips around the inner edge.

Regards
Lloyd

[ms660]

I also remember those lights at the Minack and Rowena.

Lawrence.

[Lancs Lad]

Ah, yes, Lawrence!

Rowena Cade. What an amazing woman.

[OscarFoxtrot]

Originally Posted by Lancs Lad

It wouldn't be difficult to do, and, as you say, would be safer than 240 volts if water did find its way in.

Going to construction site style 110 volts (55-0-55 centre tapped to earth) will avoid the problems of volt drop on any lower voltage and bulbs are readily available.

Not classed as SELV though I think.

[ChristianFletcher]

I don’t know about your light fitting but I have installed hundreds of warning beacon and lamps outside in the U.K. from all top manufacturers. They all leak regards of the sealing arrangement. So my advice after year of experience is you cannot keep water out. Just drill a hole so it can drain away.