Copper Fuel Lines

[Llewellyn]

There seems to be a general consensus that copper is not a good material for fuel lines. Fuels causing corrosion and vibration causing work hardening etc. I am just getting ready to install insulation and interior in my model 20 and every fuel line in the plane is copper from the factory in 1956. I would like to know the members opinions and advice before I cover them up.

[flyguy]

Re: Copper Fuel Lines

Expect you are going to get some differing opinions on this one. I have all copper lines in my -85 with 2 wing tanks. I have replaced the switch tank valve, overhauled the shutoff valve and had the left wing detached. I have found no indication of corrosion or any other kind of problem with my all copper fuel lines.
I might add, though, that I have Never, ever found any water in any of my tanks or my gascolator. I keep hearing how impossible that is, but it is true and we have some very wet winters here.
Darryl

[Forrest Barber]

Re: Copper Fuel Lines

Hmmm that is a judgement call, 40+ old lines , maybe replace ; BUT are the newer ones better or worse. I look at them and decide. Usually I am not so wishy washy. Never got water either unless the ship was out in a rain storm or worse for a long period. (abused) .

[Len Petterson]

Re: Copper Fuel Lines

If you are consernd aout copperlines being old and work hardend anil them at the end or where they pass trough a firewall etc.
Disconect them and drain well before you put the torch to them.
Do not overheat ( do red a colour just so it changes darker colour)
Remember to blow out the line with compresed air as oxidation will take place inside the tubing as well and it has to come out.
If large anount of flaking of oxidation occures on the outside it will have happeneing on the inside as well.
Make new once it is allmost as easy!
Len

[Llewellyn]

Re: Copper Fuel Lines

I think some of the concern around copper is the use of alcohol enhanced fuels. I've read where the USCG is warning boat manufacturers not to use copper fuel lines. When I removed mine, they looked OK, so for now I will just leave them be. Since Model 20's have fiberglass tanks, any alcohol enhanced fuels would be death to the tanks, the engine and possibly the pilot. Alcohol turns fiberglas resin into goo with the resulting mess finding it's way to the carb. Just hope we will be able to buy straight gasoline in the coming future.

[flyguy]

Re: Copper Fuel Lines

What is the alternative to copper? Aluminium? Stainless? Stainless would seem like a good idea. What do military aircraft use? Just curious.

Yeah, too bad about the alcohol in fuels, what a misguided mess.
Darryl

[Ron Coleman]

Re: Copper Fuel Lines

There is a serious problem with copper lines. Some years ago I pulled up to the ready line at the Daytona Speed way, all cocked and primed to burn up the track with my vintage Indian. Everyone was pumping the throttlles, the smoke and roar was marvelous and some adoring soul kept waving and pointing at me. Turns out I was sitting in the middle of a pool of gasoline. The copper line from the gas filter had broken at the carb bowl and gas was pouring down over the hot engine and under the bike. That was a costly mistake. I lost about $600, in travel money, fees and all that stuff. Besides there was only one race so I got a "no show"/

The problem is an unsupported fluid line constructed of a metal that will work harden will break if it can vibrate. It will usually break at the terminus of the movement of the line. If you secure the line so that it cannot wave around it doesn't break. I don't hesitate to use copper if it can be fastened down. I use modern fireproof fuel line on the racer bikes where it is permitted.
Like that!
RonC

[Ragwing nut]

Re: Copper Fuel Lines

Copper ages and work hardens over the years of vibration and are known to crack or break. If the lines are checked regularly at annual, should not be a problem. Aluminum tubing has been the standard for years, but is suceptable to corrosion from alcohol. That is not a problem since it is illegal to run any autogas with alcohol in it. Unless they are shown and you want to install for asthetic purposes, I would install aluminum lines.

[astjp2]

Re: Copper Fuel Lines

Try finding a spec. for the Copper lines, the FAA Could not get me one...Tim

[flyguy]

Re: Copper Fuel Lines

Been checking around. Stainless is starting to look pretty good. Must be be some disadvantage. Drop it on me.
DC

[astjp2]

Re: Copper Fuel Lines

Absolutely overkill and hard to work with, go with the Copper, it lasted 62 years in my airplane....Tim

Besides its a substitution of materials and would require engineering approval....or STC

[flyguy]

Re: Copper Fuel Lines

I have worked with steel tubing in automotive applications, and I know what you mean.
Think I will seal some copper tubing up with a little of our Calif. special brew 87 octane and see if the experts are correct about the alcohol problem.
Yes, things are pretty slow here just now LOL.
DC

[tawadc95]

Re: Copper Fuel Lines

loops in the copper lines at both ends help alot at slowing the work hardening process down.

[Ron Coleman]

Re: Copper Fuel Lines

Lets get down to the nitty gritty.
Steel lines will work harden if they can move, vibrate or get hammered on.
They rust.. Just like brake lines on a car.
Alluminum lines corrode and work harden if they move, vibrate or get hammered on and when they get old.
Copper lines corrode and work harden if they move, vibrate or get hammered on.
Copper will suffer the least on initial forming if the metal is fresh and soft. It can easily be annealed for reforming.
Neither steel nor aluminum lines like to be re-bent. They can be annealed, but not without some deleterious effects.
Copper and steel lines are easy to flare..once. Don't try to correct a poor flare, start over.
Aluminum lines can be easy to flare, but aluminum hardens with age and old aluminum tubing will often split while it is being flared.
I have had to replace a lot of aluminum fuel line all of it newer than the copper line in my T-Craft.
When I replace the fuel line in the t-craft, if it becomes necessary, I will use new soft copper and will bend it once (or replace the line) and will secure it so that cannot vibrate and will use a bend that will permit the line to expand and contract without putting stress on a bend or joint.
RonC
I think that I have all of that right.

[Forrest Barber]

Re: Copper Fuel Lines

THAT is correct , some ships have gone to aluminum lines from the factory.
The later Taylorcrafts all had aircraft aluminum fuel lines the flare is 37 1/2 degrees , the copper is 45 degrees. At some point you have to do a transition. The Model D had all copper.