I've used copper tubing from home depot to run diesel over to my 1 qt draining filter (dutton laine) on passenger side, and back to the pump, for 2 + years on 240d. No issues. I've got the copper line isolated by 2" rubber line on both ends, and clamped to firewall by tiewraps in the middle. No vegetable oil, although I do run 30% used motor oil in the summers. Have had copper from the rear gas tank to the 1 qt fuel filter on my Ford gas car for 15 years. No issues. I found metal 5/16" "brake" line would vibrate and fracture around the engine on the gas car 15 years ago. I tried to buy dead soft steel line like original transmission cooler line back for fuel use and transmission cooler line, then but nobody will sell it, they are afraid you might use it to hook up a disk brake caliper and kill yourself with it.Type L Copper line is NOT rated for pressure of disk brakes or injector lines. There is a type K copper rated at higher pressures, but not for sale in consumer quantities.

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'80 240D biege "Mercey Bird"
'80 240D light blue "Slug"
'80 300SD dark blue "Theodin"

Metallic copper will dissolve into the veg oil (any kind). Once dissolved, it is a catalyst for a well known veg oil polymerization reaction (so well known, they've named it). Polymerized oil is higher molecular weight and becomes sludgy solids at normal temperatures. Sludgy solids don't go through the IP or injectors too well.

WVO is probably the worse since it tends toward the acidic, which I'd expect would dissolve the copper faster. Heat will accellerate both the dissolving and the polymerization reaction. To be sure, not much Cu dissolves, but since its a catalyst, not much is needed.

You're welcome to borrow my 20 year old Morrison & Boyd organic chem text and read all about it if you're interested and have that sort of bent. It also covers acid or base cataylized veg oil esterfication (the biodiesel creation reaction) in the same section, but the info on the net is more in depth since it wasn't such a hugely important reaction back when my copy was printed.

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'83 300DTurbo http://badges.fuelly.com/images/smallsig-us/318559.png

Broadband: more lies faster.

Thank you. You should really post more often.

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wow, good to know. I'll be switching to steel or stainless before I attempt to run on biodiesel.

Hey PatBob,

I wonder how much difference there is between your 20yr old copy of Morrison & Boyd and my 46yr old copy??

You are so very right about the copper and fats and oils (WVO). I worked in the fatty acid industry in the late 50's and early 60's and you could spot a piece of copper tubing or a fitting a mile away, as it had that slimy oil residue all over it and it had all turned the charactistic copper Green. Can get really nasty. Stainless steel is so much better, but costs quite a bit more and has its own issues with salt and stress corrosion cracking.

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1961 190Db retired
1968 220D/8 325,000
1983 300D 164,150

I wonder how well tubing made out of carbon fiber would hold up........

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

I dont even run a copper oil pressure line in my old Chevelle anymore. Very prone to vibration issues.

Contact Federal hill Trading co. for cunifer line easily managed and very strong used for brake lines fuel lines and such, give them a call they can help you, cunifer lines in all sizes, easily double flared I use it all the time Great stuff................in my shop

Long term storage of diesel
http://amsca.com/files/Download/Fuel_news_long_term_storage_diesel.pdf

http://www.lcbamarketing.com/long_term_fuel_storage.htm

Waste vegetable oil reacts with copper to form a "greenish slime".

Material compatibility
Free fatty acids in WVO can have a detrimental effect on metals. Copper and its alloys, such as brass, are affected.
Zinc and zinc-plating (galvanization) are stripped by FFA's and tin, lead, iron, and steel are affected too.
Stainless steel and aluminum are generally unaffected.

And a full set of proper MB lines cost how much and are replaced how often ??

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1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."

Its good to see a bit of proper science being quoted in this thread!!

patbob & Lycoming-8 are on the money !! M&B is a great reference for organic reactions.
Its a pity more of the alt fuel people didnt have a look at references like that before expressing their opinions.
I think you will find that much of the more up to date info that is out there like that quoted by Roy is based on references like that.

Carbon fiber products are normally based on a polymer reinforced with carbon fiber. How good it is with any particular chemical will be more determined by the polymer used. Often polyester is used & these alt fuels as well as diesel, will make a mess of them.
If you are going to use alt fuels with higher viscosity, best use steel tube with about double the diameter and a boost pump at the tank. Trace heating along the line and a good tank heater would help.
At the end of the day, you will probably realize that the economics of some alt fuel is marginal at best.

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Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving

Copper has a tendency to crack when subjected to vibration. That is because it work hardens - becomes brittle when worked - bent, hammered, etc.

For a W123 -

The return line costs about 50 euros over here and I got one 'cos it was still in stock. The Pressure line costs over 250 euros because (so I was told) they have to make some new ones - so it seems the first person needs to pay for 5 of them! I didn't get the pressure line.

All of the dealer lines come painted and with the swaged ends. They are not pre-bent (except for a single fold - that's not in a handy place - so they can fit in the post).

Is this a pressure application? If not, then a 25ft roll of low psi rubber hose will do an entire 123 with about 10 inches left over.

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