LED christmas light waterproofing test.

Followup video https://www.youtube.com/watch?v=4AuWzHspKXw
Anyone who has used the standard "outdoor" LED Christmas lights (fairy lights) in a wet environment will have noticed that they inevitably go a bit brown and rusty looking and eventually fail. This is because most LED strings for home garden use are not actually waterproof at all. Each lamp consists of an LED a spacer and a bit of heatshrink sleeving to hold them together and offer some protection. When these lights get wet the water wicks up inside the sleeving by capillary action and causes rapid rusting of the LEDs leads due to the presence of DC voltage accelerating electrolytic corrosion.
This ongoing experiment involved getting a set of 20 battery operated lights with clear sleeving and dividing them into three short strings of six. I drilled six 5mm holes in a bit of wood to hold the LEDs upright and then applied a drop of 3-in-1 oil to the wire entry point of one set of six LEDs. Then I applied a drop of WD40 to the wire entry point of another set of six LEDs (quite messy when you're trying to control the output from a pressurised can). Finally there is one set with no oil at all for comparison purposes.
The bunch of lights are now hanging outside in my garden lit 24/7 to see how they fare in the weather. I shall report back in due course with the results of the test.
It's worth mentioning that the LED lights used on city-centre trees are usually professional grade lights where the wire is heavier and each LED and its connecting wires are immersed in a little plastic thimble full of resin to form a completely sealed light. These are suitably expensive though, and not always easy to find for home use.