Fuel tank access port

[S/V Laura Ellen]

I need to cut a hole on the top of my copper fuel tank to gain access to clean the tank. Currently the engine fuel supply and fuel return are connected to the bottom of the tank. I want to cap these connections and run the fuel supply and return lines from the top of the tank.

The only solution that I've seen so far to close the opening on the tank is from SeaBuilt. www.seabuilt.com

Are there any other products out there that does the same thing?

[pcford]

I believe that copper is a no-no for a diesel fuel tank. Have heard some spectacular stories.

"Copper reacts with the sulphur in diesel and can be eaten away." Dave Gerr

http://books.google.com/books?id=euQ...sult&resnum=10

[TMny]

I believe copper is also not suited for gasoline , though i'm not sure why.

In both Europe and USA , virtually all the sulfur has been removed from 'over-the-road' diesel fuels {dunno about marine/Canada}.

If the tank is 'existing' are we sure it is copper , not desirable Monel ?

If a new install , could not plastic be used? My Saturn car has a plastic tank , cheap in junkyards !

[Dan McCosh]

I have a copper fuel tank for gasoline, and have also been told it is unsuitable for diesel, but don't know why. As for an access port--it would seem to be a simple thing to fabricate from sheet metal, with the cover held by screws, with a gasket, etc.

[S/V Laura Ellen]

I believe that copper is a no-no for a diesel fuel tank. Have heard some spectacular stories.

"Copper reacts with the sulphur in diesel and can be eaten away." Dave Gerr

http://books.google.com/books?id=euQ...sult&resnum=10

Thanks for the information... not exactly what I wanted to hear, but valuable none the less.

The fuel tank has been in service for approx 70 years, holding diesel for probable the last 40 years. Sounds like I will need to replace the tank with a more suitable material. Since the shape of the tank is very custom, a plastic tank is not an option. Looks like it will be aluminum or 316L stainless steel.

[S/V Laura Ellen]

I discuss the issue of using a copper fuel tank for Diesel fuel with a very knowledgable metalurgist that specialized in the pertochemical field (read this as 30 + years of service at a company that produces diesel fuel). His commemt was that copper and diesel fuel are compatible and there is no testing documentation to suggest that there would be a problem. I also inquired about the solder used in the custruction of the tank and again the answer was that there should be no problem.

The only other problem that could possibly exist is that the copper could have some chemical effect on the fuel. No definative information was available to indicate this would be a problem.

There have been some reports of a possible problem with Biodiesel.

[pcford]

His commemt was that copper and diesel fuel are compatible and there is no testing documentation to suggest that there would be a problem.

Then why does the opinion exist? Other people than the quote that I furnished feel the copper and diesel are a no-no.

[Hwyl]

Allan, I have no information on the copper diesel controversy.

i have had a badly installed plat as you show leak/ It was a stainless tank and pretty thin. I fixed it with gasket good and a lot of smelly work. It seemed a bit inadequte to me as it relies on friction not to get displaced.

Since you are in a rebuild mode. I'd look at having an oblong tapped plate brazed to the top of the tank and a cover for that. Are you going to fit a dipstick to the inspection plate? Had you considered a Racor right at the tank?

[Bob Cleek]

It was, I believe, not uncommon in times past to "tin" the inside of copper water tanks, at least, with a wash of tin, hence, "tinned copper." This may have been for the purpose of preventing copper leaching into the water, but I'm not sure.

Every tank should have internal baffles and an access port to permit cleaning and inspection. You can buy a ready made access fitting, but I expect they are much more expensive than making your own. All it takes is some bronze plate. Cut the ring and the cover out of the plate. Drill and tap holes in the ring to accept threaded bronze rod stock. Drill corresponding holes in the cap and cut out a gasket for the seal and drill holes in that. Braze the ring to the tank. Bolt the cap plate onto the ring and it's a done deal. You ought to get your local sheetmetal or machine shop to do the job for a very reasonable amount. You can also mount your top mounted fuel supply line through the cap. This allows easy access to the tank by getting it out of the way when you have the cap off the access hole. I also put a spud and nipple in the access plate so I have a hole to drop a dip stick in to check fuel level.

[S/V Laura Ellen]

Then why does the opinion exist? Other people than the quote that I furnished feel the copper and diesel are a no-no.

The texts that he has along with current material specs show they are compatible. It's a quandary? Since I'm in doubt, I'll inspect the tank to see if there is any signs of corrosion. If there hasn't been corrosion in better than 40 years of service , I won't sweat it.

If there are signs of corrosion, I'll replace the tank.

[Hwyl]

The texts that he has along with current material specs show they are commpatible. It's a quandry? Since I'm in doubt, I'll inspect the tank to see if there is any signs of corrosion. If there hasn't been corrosion is better than 40 years, I won't sweat it.

If there are signs of corrosion, I'll replace the tank.

I'd check with the appropriate regulatory agency (Maritime Canada?) or do it through a Canadian NA.

[Peter Eikenberry]

This is very interesting. I have been dealing with fuel tank issues for over 25 years and never heard that there was a problem with copper and diesel. The ABYC standard H-33 on diesel fuel system even specifies copper as a tank material, along with copper-nickel, nickel-copper and copper-silicon. frankly copper tanks used to be quite common 50 or more years ago. There is a problem with copper and other materials such as aluminum. Copper and aluminum are incompatible. But that's not the issue here. I would like Dave to explain where he got the information that casued him to make that statement. It would certainly be interesting to know. If the problem is sulfur, well most diesel today is low sulfur diesel anyway.

I looked up TP 1332E for the Canadian standards for fuel systems and it cites the ABYC standard but adds a note that copper must be internally tin coated. That is not in the ABYC standard so it must be something specific to Canada.

[Ron Williamson]

I thought the problem was with diesel and zinc, ie.galvanized steel.
R

[The Bigfella]

I've heard a few things about copper - one being issues with sulphur and copper reacting.

A quick google brought up a few issues re testing for copper corrosion, work hardening of copper fuel pipes due to vibration, causing them to become brittle and this one which talks about copper acting as a catalyst that leads to gum and deposit formations.

http://www.liquidintelligence.com.au/SB/200SB.pdf

Grantala's original 1937 tanks that I cut out a few years back were tinned brass.

[SV Papillon]

doesn't specify "type of fuel" but this is a USCG req
FEDERAL LAW
183.538 - Metallic fuel line materials

Each metallic fuel line connecting the fuel tank with the fuel inlet connection on the engine must:
(a) be made of seamless annealed copper, nickel copper, or copper nickel; and
(b) except for corrugated flexible fuel line, have a minimum wall thickness of 0.029 inches.

it would seem they are ok with copper