Brass Tubing Disentigration?  
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Brass Tubing Disentigration? - 11/23/2002 11:17:40 PM   
FalconWings10



Posts: 392
Joined: 11/20/2002
From: State College, PA,
Status: offline 		Sound strange, I built a new airplane this summer and flew it for 3 months. Brand new Sullivan fuel tank with new brass tubing. Wildcat 10% fuel.

I noticed that I could fill the plane and the plane would run fine. Then, after a month or so, I could still fill the plane but it was starting to deadstick in the air after about 4 minutes run.

I also noticed that at the end of the flying day that my pump wouldn't pull the fuel back out of the tank. This went on for awhile before finally I tore into the plane and pulled the tank out. What I found astounded me. The pressure side brass tubing just fell off in my hand and then while removing the screw from the stopper, the carb side did the same thing!!!????

Both had come apart right at the outside edge of the stopper. The brass was black and looked like it had be desolved by acid!
Called Wildcat and said that it wasn't their fuel that caused the problem. I believe them.

Has anyone ever seen anything like this before???
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Brass Tubing Disentigration? - 11/24/2002 12:48:08 AM   
Steve Guinn



Posts: 835
Joined: 8/23/2002
From: WV
Status: offline 		Are you sure it was pure brass tubing?

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Brass Tubing Disentigration? - 11/24/2002 1:04:21 AM   
FalconWings10



Posts: 392
Joined: 11/20/2002
From: State College, PA,
Status: offline 		Steve, how's things going down in the mountain state? Ya, it was the one that came with the new tank.

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Brass Tubing Disentigration? - 11/24/2002 1:12:55 AM   
Steve Guinn



Posts: 835
Joined: 8/23/2002
From: WV
Status: offline 		Things are great, here. Especially after that VT win. Miss you Lions.
Never heard of brass being eaten like that. Maybe the supplier slipped something over on them. All I can suggest is to try new tubing and see if it happens again.
Maybe someone a little more knowledgeable on the subject will reply.

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Brass Tubing Disentigration? - 11/24/2002 2:54:58 AM   
FalconWings10



Posts: 392
Joined: 11/20/2002
From: State College, PA,
Status: offline 		Thanks for the reply. I've taken the same tubing and I've been letting it set in the same fuel since September. It's done nothing.
PS, I grew up in Charleston. Just a misplaced WVU fan.

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Brass Tubing Disentigration? - 11/26/2002 9:20:02 PM   
hauckf


 

Posts: 187
Joined: 3/1/2002
From: Decatur, AL, USA
Status: offline 		Years ago I built a fuel can with a solid brass tube that went from the cap to the bottom of the can, and had the same problem. In my case, the corrosion created a lengthwise split in the tube. Maybe someone else out there can explain why this happens. I just assumed I had gotten a piece of poor quality tubing.

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Brass Tubing Disentigration? - 11/26/2002 9:56:19 PM   
FalconWings10



Posts: 392
Joined: 11/20/2002
From: State College, PA,
Status: offline 		Both of my fuel line tubing dissentigated at the very edge of where it comes out of the stopper. ??? It was black (and dissolved) like it had been burned!

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Brass Tubing Disentigration? - 11/26/2002 11:01:03 PM   
JimTrainor


 

Posts: 1308
Joined: 10/25/2002
From: Ontario, ON, CANADA
Status: offline 		just a few wild, brain storming, guesses:

Here's a page that says oxidizing materials such as ammonia can exacerbate brass corrosion:

http://www.corrosion-doctors.org/MatSelect/corrbrass.htm

Do you use a cleaning product high in ammonia (window cleaner)?

Another remote possibility is that the brass fuel tubing has somehow got itself on the ground side of an electric circuit. Seems pretty unlikely, and I'd have to double-check the chemistry to be certain it was possible. Do you have on board glow ignition?

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Brass Tubing Disentigration? - 11/26/2002 11:34:49 PM   
JimTrainor


 

Posts: 1308
Joined: 10/25/2002
From: Ontario, ON, CANADA
Status: offline 		... another thought

Was the fuel tubing always drained? I'm think that if there is a conductive path (the fuel) between the engine and the brass tube then there will be galvanic reaction that will consume the brass.

It's like sticking a penny and nickel in a lemon. It creates a small battery. If you close the circuit current will flow and the penny will slowly be consumed. The nickel will be fine - it's not suppling the electrons.

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Brass Tubing Disentigration? - 11/26/2002 11:41:23 PM   
FalconWings10



Posts: 392
Joined: 11/20/2002
From: State College, PA,
Status: offline 		Interesting web site. The only thing that I can think of is; I used Innovative Products P.F.M. adhesive on the windshield. It has a very strong ammonia smell when used. Could this be the problem. I'm going to perform some test.

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Brass Tubing Disentigration? - 11/26/2002 11:46:02 PM   
FalconWings10



Posts: 392
Joined: 11/20/2002
From: State College, PA,
Status: offline 		It is possible that there was enough fuel in the tubing to cause galvanic reaction. An interesting thought. Not sure what the dyelectric properties of the fuel is.

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Brass Tubing Disentigration? - 11/28/2002 3:49:17 AM   
JimTrainor


 

Posts: 1308
Joined: 10/25/2002
From: Ontario, ON, CANADA
Status: offline 		I stuck a length of brass tubing (from a Sullivan tank) and a nail (plain shiny finish nail) in Omega 15% fuel and measured around a 150 mV potential and 0.3 uA when shorted by my meter. My meter is cheap but the signal was clear nonetheless. Meter showed 0 volts and 0 amps open circuit, and measured the values above closed circuit.

The brass tubing was the negative terminal, as expected.

So, it seems feasible. I have no idea how long the brass would last under those conditions. Who knows... maybe if you worked it all out it would years, maybe months... ya never know. Interesting though. There may be a combination of factors at work.

A plumber is careful not to to hang a copper pipe using steel strapping for exactly these reason. So it is a real concern.

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Brass Tubing Disentigration? - 11/28/2002 4:57:29 AM   
FalconWings10



Posts: 392
Joined: 11/20/2002
From: State College, PA,
Status: offline 		Interesting thought Jim. The only problem is time. If I did leave fuel in the tube; it didn't stay there very long because I fly this particular plant alot.

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Brass Tubing Disentigration? - 11/28/2002 5:53:02 AM   
Eaglewatch



Posts: 106
Joined: 4/15/2002
From: Crapo, MD, USA
Status: offline 		I seem to recall reading a few years ago that the nitro in model fuel can react with the brass tubing in the fuel tank. What I remember (may be incorrectly?) was that the brass can "neutralize" the effectiveness of the nitro, making the fuel less powerful. This does not happen instantly, but the idea was not to let fuel sit in the tank for long periods of time before you use it (like over a weekend or longer). Perhaps this action also has a negative effect on the brass as well? Any "fuel chemists" out there want to respond?

Regards,

Al Parry
[email]amp@intercom.net[/email]

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Brass Tubing Disentigration? - 11/29/2002 10:13:04 PM   
rcwacogeorge



Posts: 34
Joined: 10/29/2002
From: Wichita, KS, USA
Status: offline 		Hi Guys
I'll throw my two cents worth into this subject: I too have had the splitting of the brass tubing as described by hauckf. My experiences have been in old fuel tanks (3+ years). I have 20+ airplanes and have been flying for 40+ years and have seen the lengthwise splitting at least 10 times, but I have never had the tubing actually disintegrate!
Hey Eaglewatch....Is that a constellation from Bob Smith plans in your picture? I have the plans and am contemplating building with 4 OS 90 4 strokes for power.... any suggestions or advice would be greatly appreciated!!!

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