I was able to cut and flare the 42 year old water lines to relocate the water heater and to add shutoff valves at each sink. No problem.
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Thread: Coupling Old Copper Fuel Lines
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01-23-2020 06:41 AM #11
Re: Coupling Old Copper Fuel Lines
1977 Hatteras 58' MY, Hull No. 304, 4-stateroom galley up model with 8V71TIs in Knoxville, Tennessee
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Re: Coupling Old Copper Fuel Lines
I have completed several flares without issue. If it would not flare it was way to fragile to keep anyway.
The weakness I always found was easy to see from from outside corrosion caused by mix of water, bad grounding, and dissimilar metals. problem could be very localized, I think water being the main contributorRay
1983 61CY 319
AnnaVal
Jacksonville FL.
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01-23-2020 09:36 AM #13Senior Member
- Join Date
- Jul 2007
- Posts
- 1,001
Re: Coupling Old Copper Fuel Lines
I don’t see how clamped and secured copper lines could become work hardened. All they do is lay next to the bulkhead. If they were unsupported and vibrating, then yes, they will become brittle, but not simply from aging. Corrosion is a different story, but clean correctly secured copper should last nearly forever without embrittlement.
Michael & Beth
Hull Number CV312
63’ Cockpit Motor Yacht
1986 model launched in August 1987
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01-23-2020 10:06 AM #14
Re: Coupling Old Copper Fuel Lines
HAH, made me Google that and learned a new word...., right up there with "lubricity".... Cool!
Embrittlement is a loss of ductility of a material, making it brittle. Embrittlement is used for any phenomena where a hostile environment compromises a stressed material's mechanical performance.1978 53' Motor Yacht "LADY KAY V"
Hull number 524
Chesapeake Bay
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01-23-2020 12:45 PM #15
Re: Coupling Old Copper Fuel Lines
If it is too brittle to flare then I would consider replacing it back to the point where you have good copper. The reason it is "brittle" is because the thickness of the copper has been reduced (eroded away) by corrosion to the point that the tubing wall is so thin that it will just tear when you try to flare it. That is if you can even get the flaring tool to clamp tight enough to hold the tubing.
When I replaced the copper water lines in my '76 46C there were lengths that were corroded to the point that you could just twist them apart with little effort and then other sections that looked like they were put in last week. Those sections were just as malleable as new copper line and could be flared just like new line.
The danger of sliding fuel line over the old corroded copper and clamping it is that if the copper is so thin that it can't be flared, it is thin enough that it could easily be crushed by the force of the clamps."The only thing that always works on an old boat is the owner" - Some Wise Guy
1976 46' Convertible
Old Fort Bayou
Ocean Springs, Mississippi
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Re: Coupling Old Copper Fuel Lines
Pascal
Miami, FL
1970 53 MY #325 Cummins 6CTAs
2014 26' gaff rigged sloop
2007 Sandbarhopper 13
12' Westphal Cat boat
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Re: Coupling Old Copper Fuel Lines
Pascal I'm scared somebody is going to take the easy rout and use a Sharkbyte on a fuel line one day.
CRICKET
1966 HAT50C101
Purchased 1985 12v71Ns
Repowered 1989 with 8v92TI
Repowered 2001 with 3406E
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01-23-2020 04:26 PM #18
Re: Coupling Old Copper Fuel Lines
Swagelok is the compression fitting that does not leak, overkill for low pressure systems, and pricey, but they don't leak
Bill
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01-23-2020 05:41 PM #19
Re: Coupling Old Copper Fuel Lines
But are Swageloks acceptable for use on a diesel fuel line? Otherwise, it seems the only option is to try flaring with the possibility that it could lead to full replacement.
Robert
MANCHIONEAL
1973 43DC #365
Mattox Creek, VA
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01-23-2020 05:55 PM #20Senior Member
- Join Date
- Jul 2007
- Posts
- 1,001
Re: Coupling Old Copper Fuel Lines
We used swageloks to install flight test instrumentation on the first 5 C-17’s. Including fluid lines with no leaking. We used cryofit on the 4000psi hydraulic lines, but swagelok everywhere else. I would have high confidence using swagelok on fuel lines on a Hatteras.
One other curiosity is that copper is the only metal that is quenched to anneal, I’m sure you all know this, but I’ve always found that to be an interesting factoid. Heat it to red hot and cool rapidly in water which is also used to harden steels.Michael & Beth
Hull Number CV312
63’ Cockpit Motor Yacht
1986 model launched in August 1987