Leak Testing

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Leak Testing

Postby Shadow Catcher » Wed Mar 28, 2012 7:21 pm

One of the aspects of what I used to do in non destructive testing was leak testing, and I was able to exercise that very simple skill on Compass Rose yesterday and today.
The addition of the Bullfinch gas point required an additional tap on the propane line. One of the problems with CR was that the gas line from the tongue was black iron and the lowest point was that pipe under the axle.
I took the opportunity to replace it all with 3/8 copper and that includes 20' of pipe and a boat load of flare fittings, and most of them leaked. How did I know, I used a fairly concentrated solution of Dawn (dish washing soap) and it bubbles with each leak. You do NOT want to use fire to inspect for leaks and you do not particularly want any potential flame or spark source. One alternative would have been to use compressed air and I should have made up an adapter to do that.
The addition of the Bullfinch shower point required cutting the PEX tubing and installing T's and angles (space was too limited and PEX does not bend all that well). Rather than having water fountaining all over the place I used the air compressor adapter used to blow out water for winterizing to pressurize the system and the same testing mixture.
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Re: Leak Testing

Postby Wobbly Wheels » Tue Apr 03, 2012 8:40 am

Mild cleaners (like dishsoap) are great for finding leaks, but one caveat is that if there's ammonia in the cleaner, it can harden and crack brass fittings over time. There is also a product you can get (the name escapes me atm) that you paint on the fittings. It goes on purple and, in the presence of LPG, it turns black so you can see if the fitting has been leaking.
A potential problem with compressed air is that you can introduce moisture into the line if you don't have a separator/drier on your compressor.
Just curious, did you use crimp rings on the PEX or O-ring fittings like Neptune or Sharkbite ?
I'm always interested to know how others do things...
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Re: Leak Testing

Postby Shadow Catcher » Tue Apr 03, 2012 9:51 am

I would probably have been money ahead if I had bought the tool to do the crimp rings. I spent way too much for Sharkbite fittings. I did have to find a couple of Whale fittings to adapt the mm to inch fittings from the Bullfinch shower point, the West Marine store in Toledo found them for me. It is all together now and the gas line is not leaking down.
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Re: Leak Testing

Postby Wobbly Wheels » Tue Apr 03, 2012 8:02 pm

Shadow Catcher wrote:I would probably have been money ahead if I had bought the tool to do the crimp rings.


Thought you might get a kick out this...I'm working on a sailboat at the moment and the owner had some guy come in to install a hot water tank and then he declared that the domestic system needed to be replumbed as well. Now, normally when you're plumbing a boat you try and eliminate as many fittings as you possibly can because all fittings eventually leak (not really, but that's the best mindset to use in marine plumbing...).
This bozo went out of his way to jam in as many fittings as he could bill for...and used crimp rings to do it. I also found the crimping tool that he used so he apparently billed the owner for that as well...surprised he didn't take it with him.
Here's the plumbing at the water pump:
Image

And here's one reason not to use crimp rings in a boat (or an RV, IMHO):
Image
That's rust tracking down from the 90 in the center of the frame....after only two years in service.
I wouldn't think the swaged rings would stand up to vibration very well, but I haven't seen tests on them to know for sure.

Another (compression fitting) option is called Qest. You tighten the plastic long nut until it squeaks. They were quick to install and I don't recall having any leaks on testing, but it was a long time ago. O-ring fittings (Neptune) can leak if the pipe is scratched longitudinally, if the ring gets cocked, if the pipe isn't pushed all the way in, if the cut end isn't square, etc. On a big job, you're always chasing leaks left by the 'Friday afternoon' crew...

...Whale fittings to adapt the mm to inch fittings from the Bullfinch shower point...

Hehe...I noticed "installs with a 60mm cutter" instead of "2-1/4" hole saw" :lol:
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Re: Leak Testing

Postby Shadow Catcher » Tue Apr 03, 2012 9:23 pm

I had to buy the 2 1/4" hole saw. Every time I drill a major hole in the side of CR, and there are now a bunch of them now, I end up buying a new hole saw. I now have a real collection and for any one interested buy good ones i.e. Milwaukee.
I was working on installing bubble mounts on the water pump to lessen vibration/noise (It worked) and I opened up the connection at the pump to remove it and out sprayed some of the RV antifreeze. It had been pressurized for over a week so I guess it is safe to put water in it.
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