Water indicating crystals

Most chemicals I can think of that have a clear colour change eg copper sulphate, cobalt chloride etc will eventually change due to atmospheric moisture.

I tend to tie/wire a piece of kitchen towel around the suspect device or newspaper for a large pipe. This will usually stay wet after the leak has self sealed and even if the pipe runs hot enough to dry the tell-tale, it will have changed visually enough to indicate if there is a problem.

hth

Bob

I wonder if almost any powder will sort of coagulate and form a crust if wetted, sufficiently to see that it had got wet. We feed the wild birds with porridge oats and that cetainly changes its appearance after rain. Worth a test or two with whatever comes to hand.

Henry

You can also try a small bad of silica gel as this changes colour from gold to blue when it absorbs water.

Traditionally, anhydrous cobalt chloride paper is used in chemical tests for water, it changes colour from blue to pink but as someone else has pointed out, over a period of time this will absorb atmospheric moisture unless in a dry place (although it ought to be dry and warm near the boiler which would mean you would have to check it every few hours as the drying effect could reverse the process). If you know a governor or someone who works at your local comprehensive school they should be able to scrounge some from the chemistry department.

I bought a water sensor from Lidl for about 5pounds some years ago which worked quite well. It gave off a loud noise. The following would be similar:

I used it to confirm that there was an intermittent leak from the back of the washing machine. I don't seem to be able to find it now - may have lent it to someone.

Alan

If you could inject something like Fluorescein dye into the water you could then use a UV lamp to check if/where there are any leaks. Fairly small quantities light up really well in UV.

I once had a retinal examination that involved injecting some of that stuff into my bloodstream...later that day I had a slash in the gents at a local pub - trough-style urinal & there was a UV tube illuminating the place. Completely freaked out the guy that was standing next to me ;-)

Regards, Tony

Tony oh Tony ! Only you !!!!!!

AWEM

I have heard of the Dong With The Luminous Nose, but never a Man With The Luminous P**s.

Cliff Coggin.

...or even the man with the luminous dong...

Regards, Tony

Reminds me of a friends mother who went to the likes of an Anne Summers party and they were shown glow in the dark condoms. On the way home it seems they passed the local airport where a plane was being guided in by someone waving those torches with an illuminated wand end and that had them in hysterics after the glowing condom demo.

Water (as opposed to atmospheric moisture) indicators are used to detect "water" (usually beer or the contents of a toilet) damage to mobile phones. See eBay item 110781703809 for an example of such. They only (and irreversibly) change colour if liquid has been present.. Basically they are a non hygroscopic powder dye on an absorbent substrate. Any Dylon type dye powder in a filter paper wrapper will do much the same although in a damp atmosphere the home made version will discolour in a few weeks.

Teabag? Once wet it goes (and stays) brown.

-- Peter F