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  #1  
Old 03-10-2017, 03:53 PM
Ottoman Ottoman is offline
 
Join Date: Sep 2016
Location: Burnsville, MN
Posts: 4
Default Tank air pressure

How much air pressure should I use when testing my tanks for leaks? If I use the balloon method, should I pump it up until the balloon is firm?

Thanks,

John
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  #2  
Old 03-10-2017, 04:01 PM
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wirejock wirejock is offline
 
Join Date: Oct 2005
Location: Estes Park, CO
Posts: 2,531
Default Manometer

Quote:
Originally Posted by Ottoman View Post
How much air pressure should I use when testing my tanks for leaks? If I use the balloon method, should I pump it up until the balloon is firm?

Thanks,

John
I used a Manometer. 27" total. 1 psi.
Sounds like nothing but she groaned a little. Don't go more than that.
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http://wirejockrv7a.blogspot.com
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Donated 12/01/2016. Plus a little extra.
RV-7A #73391, N511RV reserved (1,800+ hours)
HS SB, empennage, tanks, wings, fuse, working finishing kit
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I cannot be, nor will I be, held responsible if you try to do the same things I do and it does not work and/or causes you loss, injury, or even death in the process.
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  #3  
Old 03-10-2017, 07:43 PM
rv7charlie rv7charlie is offline
 
Join Date: May 2006
Location: Pocahontas MS
Posts: 1,781
Default

+1 for the manometer. Honest and repeatable.
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  #4  
Old 03-10-2017, 10:06 PM
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N526JS N526JS is offline
 
Join Date: Nov 2007
Location: San Rafael, CA
Posts: 100
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Somewhere I found a pressure gauge that read to 5 psi. Cobbled up some fittings and a valve and pressurized the tank(s) to a hair past 1 psi (so I could see the "1" mark). 1 tank held for 2 days, one leaked immediately. Fortunately the leak was in the BNC fitting for the capacatance fuel quantity and easily fixed.
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  #5  
Old 03-10-2017, 11:30 PM
nilberg nilberg is offline
 
Join Date: Dec 2012
Location: Katy, TX
Posts: 96
Default

Quote:
Originally Posted by N526JS View Post
Somewhere I found a pressure gauge that read to 5 psi. Cobbled up some fittings and a valve and pressurized the tank(s) to a hair past 1 psi (so I could see the "1" mark). 1 tank held for 2 days, one leaked immediately. Fortunately the leak was in the BNC fitting for the capacatance fuel quantity and easily fixed.
After messing around with water, plastic hoses and fluctuating temperatures in the garage , I broke down and got one of these: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Apparently I can also check the static system for leaks later when I get to that stage.
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  #6  
Old 03-11-2017, 06:20 AM
N427EF N427EF is offline
 
Join Date: Oct 2005
Posts: 1,462
Default Balloon

A balloon inflated to its proper size is really all you need.
When inflating your tank, reduce your pressure setting on your
hose to a bare minimum so you don't accidentally over inflate.
You can spend 50 bucks for fancy equipment or 2 cents for a balloon, they both
do the same job.
4 tanks and no leaks for me using the balloon method
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  #7  
Old 03-11-2017, 06:30 AM
RV74ME RV74ME is offline
 
Join Date: Dec 2015
Location: Auburn, AL
Posts: 60
Default

Quote:
Originally Posted by N427EF View Post
A balloon inflated to its proper size is really all you need.
When inflating your tank, reduce your pressure setting on your
hose to a bare minimum so you don't accidentally over inflate.
You can spend 50 bucks for fancy equipment or 2 cents for a balloon, they both
do the same job.
4 tanks and no leaks for me using the balloon method
+1 on this...and dont forget to use a soapy solution (i used kid bubbles) to check for the leaks.
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  #8  
Old 03-11-2017, 02:13 PM
Ottoman Ottoman is offline
 
Join Date: Sep 2016
Location: Burnsville, MN
Posts: 4
Default tanks

Thanks to everyone for the quick replies, I have to scrounge up a couple fittings, then test on Monday.

John
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  #9  
Old 03-11-2017, 02:29 PM
Kyle Boatright Kyle Boatright is online now
 
Join Date: Aug 2005
Location: Atlanta, GA
Posts: 2,636
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I'm doing this today with the tanks on the -10 project. The original builder seemed to have done a conscientious job with the tanks, but there was a leak along the outboard bottom aft baffle anyway. The leak occurred in a little raised area of proseal that had a tiny little void in the center. Kind of like a 1/1000000 scale volcano.

Looking through the fuel filler hole, plenty of proseal squeezed out of the baffle/skin joint, but there are 3 places where there are small pinholes in the proseal.

Skygeek has the flowable (A) proseal pint on sale for $25, so I've got some of that on order. I figure I'll apply it inside the leaky tank with a syringe and flex tube, and will brush it on the outside of the seam. While I have the brush in hand, I'll probably brush the outside seams of all 4 tanks, on the 1% chance that it might prevent another leak.

To pressure test, I taped over the fuel cap with packing tape, capped the fuel line, placed a balloon over the fuel vent, and pressurized the tanks through Schrader valves threaded into the fuel drains. I only applied enough pressure to make the balloons taught - not expand them.
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2001 RV-6 N46KB
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  #10  
Old 03-11-2017, 02:41 PM
tgmillso tgmillso is offline
 
Join Date: Nov 2012
Location: Launceston, Tasmania, Australia
Posts: 294
Default

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.
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