Might also be a nice idea to have some silica Gell inside as well.
However, some floodlights that look like they were built to withstand a
nuclear attack on a nearby 'listed' building still get water inside,
apparently, so I think the point is that there will always be some moisture
in sealed units.
Brian

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This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Bob Minchin" wrote in message
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GB wrote:
We have an outside light - an oblong plastic thingy - in a rather
exposed position. I opened it up to change the bulb, and there was some
water inside. What's the best way to stop this?

I thought of putting a couple of drain holes in the bottom, but that
seems too bodgy even for me.

The two parts of the lamp push together with a flange, but there's no
rubber seal between them. Is there any simple way of making a seal that
will still allow me too open the lamp again to change the bulb?



It looks similar to this one:

http://www.screwfix.com/p/lap-anti-v...ack-240v/31250


But that one is waterproof!
Drain holes in the lowest point are the way to go.

An outside container is very difficult to fully seal as thermal
expansion/contraction will act as a pump admitting small amounts of water
vapour laden air. The water condenses and stays inside and on the next
heating cycle the air gets pushed out but the water does not and so it
slowly builds up as the cycle repeats.
You still really need some sort of seal against driving rain. I often use
a silicone grease - Dow Corning MS4* smeared over the sealing faces and
wipe off any excess that squeezes out when you fit the cover.

* I think it has another name now (DC4?) but my toothpaste sized tube will
see me out so I've not bought any of the new name stuff.