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  #11  
Old 03-11-2017, 04:27 PM
Kyle Boatright Kyle Boatright is offline
 
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Originally Posted by tgmillso View Post
I did both simultaneously at first. The balloon burst at .5 psi. A Balloon is simply not a reliable measurement device. Van's indicates that 1psi should be your target test value. Just don't over pressure it, so cut the hose off or bend it over at this point so you can't. I then just used the manometer and took it to 27in of head. I used some clear plastic 3/8" hose I bought at the hardware store, flared the end and used an 818 nut and 819 sleeve to attach it to the tank. You should have plenty of these in your bag of fuel fittings. It really isn't that complicated, but it is accurate.
Tom.
Soap bubbles are your leak indicator, not so much the pressure the tank holds.
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  #12  
Old 03-11-2017, 09:19 PM
tgmillso tgmillso is offline
 
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Interesting. I ran my test for a day and tracked the atmospheric temperatures and pressures to account for any differentials in the manometer height. There was no change in my manometer level once these factors were taken into account, thus I fail to understand how this is not an indicator of the presence (or lack thereof) of any leaks? I can understand using bubbles to pinpoint a leak once you have discovered that your tank does not hold pressure, but fail to see how this can provide benefit otherwise.
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  #13  
Old 03-13-2017, 03:49 AM
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longranger longranger is offline
 
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Originally Posted by tgmillso View Post
Interesting. I ran my test for a day and tracked the atmospheric temperatures and pressures to account for any differentials in the manometer height. There was no change in my manometer level once these factors were taken into account, thus I fail to understand how this is not an indicator of the presence (or lack thereof) of any leaks? I can understand using bubbles to pinpoint a leak once you have discovered that your tank does not hold pressure, but fail to see how this can provide benefit otherwise.
Tom.
If you just go ahead and use the soap, you don't have to keep track of temperature and barometric pressure changes. No bubbles = no leaks. Simple as that.
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  #14  
Old 03-13-2017, 06:34 AM
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Z-EDD Z-EDD is offline
 
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Location: Harare, Zimbabwe
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Quote:
Originally Posted by tgmillso View Post
I did both simultaneously at first. The balloon burst at .5 psi. A Balloon is simply not a reliable measurement device. Van's indicates that 1psi should be your target test value. Just don't over pressure it, so cut the hose off or bend it over at this point so you can't. I then just used the manometer and took it to 27in of head. I used some clear plastic 3/8" hose I bought at the hardware store, flared the end and used an 818 nut and 819 sleeve to attach it to the tank. You should have plenty of these in your bag of fuel fittings. It really isn't that complicated, but it is accurate.
Tom.
The instructions I have (came with the vans test kit) refer to the maximum pressure in the tank during operation being "very low, less than 1 PSI".

The manometer is then offered as an alternative to the balloon. "When the water level in the open end of the tube is 27" higher than the level in the end attached to the vent, you will have 1 psi in the tank". I do not read this as you MUST have 1psi, but rather that this is your limit. Again, the soapy water test is still specified as the method for detecting leaks.

IMO 1 PSI should be a LIMIT and not a TARGET, any positive pressure will show up leaks under the soapy water test, it doesn't need to be exact.
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  #15  
Old 03-13-2017, 06:56 AM
ka6dan ka6dan is offline
 
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A note 1psi = 144 psf. I suspect 144 psf vacuum could result in a big problem while test pressure for leaks would be the upward limit unless you want to see if your riviting will hold up. Just a thought
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