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tim walter

Well Known Member
Since all non alclad is supposed to be primed
does that mean I should prime/paint the fuel lines?

if so, what color are fuel lines supposed to be?
 
fuel line marking

If you are using an epoxy primer I would paint them with that and leave as is, I don't think the color matters. Aircraft fluid lines can be marked by tapes whose color, symbol and lettering identify the fluid being carried. In the case of fuel this color is red, as are most fuel tank caps for the same reason. Tapes are available if you should desire, check the internet. See also this resource for fabricating and marking fluid lines.
http://www.faa.gov/library/manuals/aircraft/amt_handbook/FAA-8083-30_Ch07.pdf
 
To be honest I never thought about painting the fuel lines and I have never seen one with painted fuel lines.
 
overkill

it's probably not necessary since they are always inside the cabin and not exposed to moisture ?
I've never seen them painted either
but it's just 3003 alumimium, not alclad, so technically you would expect it to need priming.
 
Fuel lines can corrode; from the inside out. I just replaced the interior cabin hard lines in my Bucker due to a pinhole that developed. The particular fuel system designed for this airplane had a low point in a reserve fuel line that allowed some contamination to stagnate in the line and over time, some 18 years, it finally developed the pin hole.

I seriously doubt this would occur in a properly maintained and operated RV.
 
JonJay said:
Fuel lines can corrode; from the inside out. I just replaced the interior cabin hard lines in my Bucker due to a pinhole that developed. The particular fuel system designed for this airplane had a low point in a reserve fuel line that allowed some contamination to stagnate in the line and over time, some 18 years, it finally developed the pin hole.

I seriously doubt this would occur in a properly maintained and operated RV.
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well priming the outside would not have helped in that case anyway.
 
3003 Aluminum has good corrosion resistance in it's natural state. Fluid lines are typically not coated.

(I did polish some of mine though!)
 
tim walter said:
well priming the outside would not have helped in that case anyway.
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Funny, well no, and priming the inside would be hard to do, and not very wise.
Interesting side note. All of the lines are painted on my G.46 projects. They are copper lines, yes, copper throughout, and they are painted for identification. I do not know what the standard is but it is well documented in the manuals and schematics, I just have to learn to read Italian better. Hydraulic lines are one color, fuel another, static, pitot, etc....
It is quite pretty.
 
Hope you know about copper and 'flexing'. Ordinary copper tubing will work harden with flexing and eventually (soon, actually) crack or split. I'm not proud to say I 'been there'. Also managed to land in at a nearby field drenched and near blinded by Avgas. No fire (obviously).
 
JonJay said:
Funny, well no, and priming the inside would be hard to do, and not very wise.
Interesting side note. All of the lines are painted on my G.46 projects. They are copper lines, yes, copper throughout, and they are painted for identification. I do not know what the standard is but it is well documented in the manuals and schematics, I just have to learn to read Italian better. Hydraulic lines are one color, fuel another, static, pitot, etc....
It is quite pretty.
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interesting.
what color are the fuel lines?
 
gossend said:
Hope you know about copper and 'flexing'. Ordinary copper tubing will work harden with flexing and eventually (soon, actually) crack or split. I'm not proud to say I 'been there'. Also managed to land in at a nearby field drenched and near blinded by Avgas. No fire (obviously).
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Scary experience. Glad the outcome was not a tragedy.
Yes, these lines will be changed out to aluminum due more to age and unkown condition than the fact they are copper. Where they are used there is no relative motion other than potential vibration and they are extremely well supported.
For what its worth, my copper primer lines in the Bucker are going on 20 years in service with no issues. They are properly supported and installed with a "loop" to isolate. However, I expect some day they will fail. Not as big of a concern as a primary fuel line for sure.
 
JonJay said:
For what its worth, my copper primer lines in the Bucker are going on 20 years in service with no issues. They are properly supported and installed with a "loop" to isolate. However, I expect some day they will fail. Not as big of a concern as a primary fuel line for sure.
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Also FWIW, my old Cherokee had copper lines for the fuel pressure and oil pressure gauges running from the engine compartment, thru the firewall, and to the gauges on the instrument panel... all from the factory. After over 45 years, no signs of failure or leakage from them.
 
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