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Author: Subject: Gas Leak Detection Spray
pHzero
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[*] posted on 25-6-2009 at 08:25
Gas Leak Detection Spray


If you scroll down on this page, they heave "gas leak detection spray":
http://www.calortoolbox.co.uk/acatalog/accessories.html

Does anyone know whats in it? My guess would be that it's a solution of SO2 in water, which reacts with the ethanethiol additive analogously to the desulfuration of diesel and suchlike:

2EtSH+SO2 ---> 3S + 2EtOH

Which is analagous to:
2H2S+SO2 ---> 3S + 2H2O

So you'd get an opaque cloud of sulfur dust. Anyone have any information/any other ideas? I cant think of anything which would visibly react with the propane/butane itself, so some reaction with the EtSH seems like the best explaination.

Are these things even useful though? Ethanethiols pretty smelly stuff. Is it probably designed for anosmics (if thats the right word)?
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UnintentionalChaos
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[*] posted on 25-6-2009 at 08:42


There's not really any appreciable amount (despite the smell) of the thiols in gas. More likely, it is a viscous noncorossive liquid that is meant to form bubbles. I've used something similar to this in a lab before.



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pHzero
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[*] posted on 25-6-2009 at 10:51


Quote: Originally posted by UnintentionalChaos  
There's not really any appreciable amount (despite the smell) of the thiols in gas. More likely, it is a viscous noncorossive liquid that is meant to form bubbles. I've used something similar to this in a lab before.


Oh right, that's a bit boring :( You could use glycerol to do that, and you can usually get it for free if you know biodiesel makers
I know the gas doesnt contain much EtSH, but I thought it might still be enough to form a visible sulfur cloud
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GoatRider
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[*] posted on 25-6-2009 at 19:08


The guy who installed my dryer used something like that, it was something soapy that would bubble with gas leaks, but also was non-corrosive so you wouldn't have to clean it up.
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DJF90
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[*] posted on 25-6-2009 at 19:08


I think you'll find ethanethiol present in gas supplies only at a concentration in the parts per million range, if not the parts per billion. Seeing any visible precipitate of sulfur is incrediably unlikely (work out how many moles/grams it is and you'll see why). General washing up liquid (Fairy or the likes) will suffice to form bubbles at a gas leak.
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IrC
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[*] posted on 26-6-2009 at 09:35


Quote: Originally posted by GoatRider  
The guy who installed my dryer used something like that, it was something soapy that would bubble with gas leaks, but also was non-corrosive so you wouldn't have to clean it up.


This is a decades old trick appliance repair people use which is merely dish-washing liquid such as Ivory and water mixed.
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Mr. Wizard
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[*] posted on 27-6-2009 at 07:23


Use the solution they sell to children to make bubbles. I use 'Mr. Bubbles'

I've been using the same bottle for about 10 years now, and it's getting a little discolored, but it still works. I use a little paint brush or disposable 'acid brush' to put it on the test areas. It's very sensitive to leaks. If you use a sprayer you are more likely to get a lot of bubbles, but a brush puts more liquid on the point of interest, with fewer misleading bubbles.

Picture 13.png - 20kB

[Edited on 27-6-2009 by Mr. Wizard]
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