Advice & info on fuel line material.

Alan S

Alan S

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Location
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I know there is a good & logical reason why copper should never be used in fuel lines, but for the life of me I can't remember. Anyone able to jolt my memory?
I mentioned it on an overseas forum and have been asked to confirm what it is but things just won't click blush
I can remember it was such a nono that once we had built up a copper swirl pot at great expense and had it fitted & had to remove it. It has been suggested that copper will self anneal, become hard & crack, but that wouldn't have been the reason for us discarding the swirl pot.
Any clues anyone? :confused: :confused: :confused:

Alan S
 
Alan,

Best I can recall is that it may become brittle and crack with time. Must be quite a long time, as my 1951 Renault 750 had copper fuel lines with brass nuts when I bought it in 1966 and they were fine.

We changed to PVC at that time, which of course means you can see what is happening, i.e. whether fuel is getting to the pump or not. I seem to recall that the mechanic who helped me working on it then commented about cracking. But they had lasted 15 years!

Cheers

JohnW

Cheers

John
 
Have just received a reply on another forum on this and as I suspected, it's a safety issue.
Chemical reactions, potential corrosion and contamination as well as the possibilty of explosion without warning eek! all come into the act.
It seems that before anything copper or brass is used in conjunction with any petro-chemicals, it has to be tested & graded and as anyone in the refrigeration trade will agree, you rarely get two coils of copper tubing with the same properties, hence whilst one (John W) may get away with it for years, someone else could just as easily blow himself to kingdom come dead
I have asked the guys approval to post his message & if forthcoming, I'll post on here as I'll lay big quids, there'd be a lot of cars in Australia with copper veins. :rolleyes:
I knew it was a valid reason why we dropped our copper bits as fast as we did; this reply is the one that rings the bell.

Alan S
 
I certainly wouldn't worry about it. If you think about it another way, a copper pipe will last ten times as long as a rubber one, and it's part of life to check rubber hoses regularly. I had six inches of copper joining two rubber ends (where I'd cut out a split)on my 12 for about five years, and that copper was fine when I removed it a couple of months ago. However, I'll go out to the shed an bend it to see if it's brittle or if there's any other effect.

I've definitely seen copper used on quite a number of 'classic' cars, with brass ends, not that this means it's OK... eek!

Stuey
 
Stuey,

The guy who originally asked the question was making noises like putting it from tank to carby. I think that is the scenario that is a big worry.
From info I've been sent, it appears that on brakes it's also frowned on. There is a material which is as cheap as copper that incorporates alloy that is recommended & apparently last almost forever. Pleiades, the Cit hydraulic specialists apparently use it almost exclusively.

Alan S
 
Here's the full text from the guy in the UK.

Copper bearing metals are infact corroded by petrochemical auto fuels including diesel, aviation fuels are also corrosive.
Fuel's have to pass a test called " the copper strip corrosion standard " which is in place to ensure fuels don't uneccassarily damage or corrode part's of fueling system's.

A copper sample with a known surface finnish is immersed in the fuel under specific conditions and for a precise length of time, the amount of tarnishing of the sample is compared with test peices, the darker the sample become's the more corrosive the fuel is.

Here is something I know about copper from using gas welding/brazing equipment.
Copper tube/pipe or fitting should never be used to transport Acetylene gas from the cylinder.
Copper and Acetylene will form Copper Acetylide, a black/brown solid wich is explosive and will explode on impact, does'nt need to be ignited, just walloped.
So check your welding and burning tackle for copper tube, if there is some and it's been there for a long time IT IS DANGEROUS, dont touch it call for help.

The only other really dangerous substance that should be kept away from copper is Hydrogen peroxide (HTP) which is not in itself dangerous, but on contact with copper or metals containig it such as brass, it breaks down and gives off Oxygen and water vapour or steam, when HTP becomes hot gas it expands in volume an amazing 5,000 times.
This would rapidly pressurise an enclosed space to the point where an explosion occurs.
It was the Hydrogen peroxide used in Russian torpedo motors that sank the Kursk two years ago.

Dave

I asked a couple of questions and asked his permission to put on here and this was his response.

Hi Alan, the copper strip corrosion test gives a rough measure of the amount of active sulphur present in petrochemical product's, sulphur is corrosive and the crude oil from the Gulf States is naturally high in it.

I personally would be more concerned by the fact that copper tube will work harden and fracture if allowed to vibrate as NiSk has allready pointed out, but then I've never seen a corroded fuel line or it's result, I suppose because it simply isn't used for that purpose.

Any member of the public may read the information contained in this forum, it therefore becomes public information and in my view you can take that information and convey it to other's, any way you like.

Dave

After placing the answer on a closed forum, we received this response from a member in the UK.

That was an interesting post about the copper piping from Dave. About two years ago, I found the plastic flow and return fitting in the top of the fuel tank on our diesel Pug 205 cracked. I repaired it with an 8mm soldered bend and two pieces of copper tubing. At the same time I renewed the flexible connection using a length of butane gas tubing. A few months later I managed to find a flow and return at the breakers, and when fitting it into my tank, discovered the butane gas tubing cracked and on the verge of collapse. Another material that doesn't like diesel.

Sorry about the size of the posting, but this guy Dave Burns comes well credentialled and never opens his mouth uless he knows the answer as opposed to thinking he does.
As this is a safety related issue, I thought it worth the effort to follow it through.

Alan S
 
Interesting stuff. I have been into Vintage motoring for years (at least 35) and in cars of the 20's (REAL Vintage) virtually all tubing is copper. The later Vauxhall 30/98s had copper brake lines, though when built the fluid was something other than today's brake fluid - metho ??. Definately petrol lines were copper, I have several cars with original copper lines still in good nick. Presume some smart folk found out something around Wartime, as cars of the 50s seem to have "Bundy" (originally laminated stell) for petrol, as well as brakes. I have always suspected copper brake lines, as modern high pressure braking circuits would be dodgy with soft copper, and deadly with brittle stuff.

Hummmm
 
Paul,

I can agree with you regards the old cars & coppr tubing. I can remember a neighbour of mine with a '27 Chev and he would religiously lift one side of the bonnet & turn the juice on before starting and off on completion. Copper pipes & brass taps were the order of the day.
My guess is that one of a couple of things may have happened. The copper & brass we get today may be of a different standard to that made 80 years ago, which wouldn't be all that hard to believe. As an alternative, it could also be that back in the days of DDT, asbestos sprays to reduce risk of explosion in coal mines and everyone smoking around 40 to 80 fags a day, that the dangers weren't recognised. I do remember that when I was told what the risks were when we fitted it up on the CX, a cold shiver went down my spine - never did harbour ambitions of doing a Saigon Buddhist Monk impersonation whilst driving a car eek! eek! blush clown :mad: :p

Alan S
 
Alan and others,

Thanks for an interesting discussion!

Tonight's recollection is that my 1951 Renault 750 is also on its original (copper) brake lines too! Makes me think!! No doubt it's an odd size and no doubt I should think seriously about changing it. The R8 copper brake lines are only 37 years old or so, but I have a feeling....

Have others actually had problems with old copper brake lines?

Advise welcome.

Cheers

JohnW
 
JohnW:
Alan and others,

Thanks for an interesting discussion!

Tonight's recollection is that my 1951 Renault 750 is also on its original (copper) brake lines too! Makes me think!! No doubt it's an odd size and no doubt I should think seriously about changing it. The R8 copper brake lines are only 37 years old or so, but I have a feeling....

Have others actually had problems with old copper brake lines?

Advise welcome.

Cheers

JohnW
Click to expand...
John,

Here's a posting directly from another board that answers you question.

"DON'T use copper in the brake lines!!! as it vibrates it case hardens and fractures (guess how I know!!!!)The stuff to use is Kunifer which is a an amalgam of metals, I don't think you can buy copper brake line in the UK anymore
The car which had the brake lines replaced with copper was a 1970 Volvo amazon, the line across the back axle fractured cleanly at one of the unions."

I won't make any comment on the brand of car it happened to :rolleyes: it'll only upset 'em :p :D

Alan S
 
G'day troops,

Interesting thread, my experience is limited to owner/maintainer not pro-maintainer.

On brakes - I have had "Bundy" tube fail. This was on an old Standard 10, decades ago. I seem to recall that it rusted through.

On fuel - the only problems I have had had have been with "plastic" or rubber bits - never with copper or brass. I usually replace buggered hoses in copper where ever practical ! When you look around there is a lot of brass in contact with the fuel from unions to jets ?

On oil - my father had a length of copper to replace a damaged bit of hose on the auto transmision cooler line for years (and years) with no adverse affects.

To defeat vibration problems the tube needs to be solidly supported but you won't beat expansion and contraction which will also harden the tube over time - a real long time. I usually use copper for the "long bit" and hose for the end connections for fuel and cooling water situations that need "fixing".

Why did the manufacturers stop using copper ? I would suggest that Bundy tubing and rubber hoses was easier and cheaper.

Keep posting
Bob
 
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