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Copper Primer Line Flare

Mark7986

Member
How has everyone flared their copper primer line. My flaring tool (which is almost new) is so sloppy I can't get a good flare on the 1/8 inch line. Any help will be appreciated.

Thanks
 
My order of preference:

1) Dump the primer lines, nothing but trouble.
2) Eliminate the primer lines, they are going to fail.
3) Get Stainless steel lines.
4) Solder them.
 
Stainless injector lines all pre-fabbed have been great for me for 1000 hrs. It seems that I'm the only one that loves my primer system. I use it on every cold start in hot, very hot, and cool weather. Works for me, perfectly.

Funny story about cold: Tanya fired up at Petit Jean one "cold" morning last season and we all thought one ignition had failed! I started walking across the ramp with that (Oh, ****) feeling while she let it run. I wiggled the wing tip and walked up to the cockpit and asked her "what is the deal?". "It is fine, just cold." :). Ok.
 
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Other than getting rid of them (not needed with FI), SS or teflon lines from Tom (above) is your best bet.

When you have copper it's not if they'll fail but when.

Oh yea, never use copper line in between the primer valve and fuel supply, if that line breaks you'll be spraying fuel everywhere when you turn on the electric pump or be sucking air into the engine pump, neither one is good for your health!
 
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For what it's worth, my 1955 Cessna 180 has OEM copper primer lines and there has not been an AD on them.

That suggests that the fleet experience is favorable. It's not entirely gloom and doom, apparently.

On the other hand, and this might invalidate this experience for RVs, since the Cessna 180 uses gravity feed for the fuel. Still, I'd think that if a line was going to crack it would regardless of whether the fuel system was pressurized, and that fuel leakage from a cracked primer line would show up on an annual inspection, by sighting the stains.

My plane has had two engine removals and installations since new.

Dave
 
It has been a long time ...

I have 1/8" copper lines with approptiate strain relief loops to 3 cylinders and have experienced no trouble with them (coming up on 700 hours and 8 years of operation). They do require some special work with solder and fittings at the cylinder end (see ACS catelog in the tubing fitting area) but I guess you know that and only want an answer to your question. I bought a Parker Hannifan (sp?) flare tool that was supposed to work for several sizes of tubing including 1/8" but it just made a mess of my copper tube ends. I went to the Aircraft Spruce catalog and found a dedicated 1/8" tubing flare tool that worked for me. It consisted of a pair of metal blocks that clamp around the tubing and has the female flare cone machined into one end around the tube hole and punch/pin male tool that gets tapped into the open end of the clamped tube. Sounds crude but it worked fine for me.

Bob Axsom
 
flare tool

I too used the ACS tool for my fittings and it worked well. FYI...do some training on scraps to perfect your skills. Look at the tiny cut end carefully before you start to flare. The tubing cutter leaves a rim inside the tubing, so I used a tiny drill bit to clean the debri and make sure the inside diameter was clear. took my time tapping the mandrel with many small blows, being mindfull of a centered flare. Once flared I filed the outer edges to remove any cracks in the copper to prevent future cracking and make sure the outside diameter is correct to fit inside the fitting. After you do a couple samples you feel very good about your flares. I also dipped the mandel in oil before I started tapping on the metal to help it form the metal smoothly instead of possibly scarring it. It is tiny work for big hands and tools but I felt very good about my results. Good Luck with your system.
 
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Other than getting rid of them (not needed with FI), SS or teflon lines from Tom (above) is your best bet.

When you have copper it's not if they'll fail but when.

Oh yea, never use copper line in between the primer valve and fuel supply, if that line breaks you'll be spraying fuel everywhere when you turn on the electric pump or be sucking air into the engine pump, neither one is good for your health!

Do you know of a good source for stainless line? I haven't seen annealed SS line on ACS or other sources.
 
The Best Primer Lines, in my opinion....

The Best Primer Lines, in my opinion are stainless steel with AN800C2 on each end. Then you need the correct fitting, they are the are like the ones that are in the fuel distributor on top of the engine if its fuel injected. But if you have that, you dont need a primer setup.

The cone fittings need to be silver brazed onto the line.

See links for pictures and part#'s

http://www.gen-aircraft-hardware.com/images/pdf/ftgspcl.pdf

The components are not cheap so if you want to save money go with the straight ones instead of the forged ones.
See Tubing Here http://www.gen-aircraft-hardware.com/images/pdf/tubing+info.pdf
 
The other end

I used the primer fittings that are soldered on to the 1/8" copper tubing (page 99 in the 2011-2012 ACS catalog) and silver solder. It is not like SN60 or SN63 solder with a melting temperature that can be handled by a pencil like soldering iron. I used the small butane torch sold by ACS (page 730) for approximately $68. I was concerned that I might run out of butane and wanted to finish the job once I started. I had a little trouble finding a source but I bought some extra bottles at a film industry store in Los Angeles. It turned out I shouldn't have wasted my money - I did the job and I am still on the original bottle. However, if one should break someday I have the gas and the tool to do the job.

Bob Axsom
 
Copper lines . . .

...do not belong on an airplane. See my post of how fast and how bad an RV-6 burned when his primer line broke during run up.
 
I will jump in on this boat again, I also highly suggest staying away from the copper lines. I posted on another thread around 2 weeks ago where another gentleman was setting up his primer line setup. I have converted MANY Lycomings from the copper to stainless after finding the brass nuts split from age and normal vibration, or broke off at the solder point. I was doing an annual on a Beech Musketeer last summer with an O-320 when I noticed one of the lines looked like it was separating, when he gave the system a pump of go-go juice, all three ends leaked gas down the side of the cylinders, and no, the nozzles were not clogged. I understand SOME of the aircraft owners on here have not had problems with their copper lines, but for people like Walt and other A&Ps on here that inspect GAs very frequently, you will get a very consistent answer from their experiences. Save yourself from being stranded away from home on that X-country and take the steps necessary to ensure the safey of you and your aircraft by using SS. You will still be able to put that shiny new flaring tool to good use with the stainless too :D
 
So are manifold pressure lines.
Properly installed copper lines, relieved with loops should last decades as they have in certified airplanes.
I am sure stainless line or teflon hose is even better but at 10 times the price.
I know some of you are going to say it's not a big deal in the grand scheme
to spend an extra $50 bucks for "proper" primer lines. Next are fuel lines, not to be made up by amateurs, 50 bucks here a hundred there, before you know it you spend an extra couple of thousand to build a space shuttle quality aircraft, it' only money as they say.
I can't dispute what the APs tell you but surly they have also seen cracks in Lycoming cylinders and broken con rods, busted valve rockers and even crankshafts that broke in half and we still use the same lycoming engines.
Bottom line, if you are not sure about what you are doing, either educate yourself or just do what the experts tell you.
The fact that you are asking tells me that you are educating yourself, good for you.
 
The perils of copper demonstrated

After this thread resurfaced last week, once again questioning the appropriateness of copper used for primer lines, I got a bit paranoid and went and checked mine a bit more thoroughly, having just done an examination of the system for my condition inspection a couple weeks ago. Guess what I found after wiggling each of the lines gently where they went into the cylinders?


2vb4t93.jpg



Now, I'll be the first to say that it's entirely possible I did the initial installation wrong. At the same time, however, I did it similarly to all my other aluminum lines and followed the instructions that came with Van's primer kit. Thus, it might be considered a cautionary tale for anyone who, like me, is not an expert in copper line installations.

Needless to say, after discovering this, I immediately pulled out all of my primer lines and capped the upper port on my gascolator. This part of the year the primer system is not really needed anyway. Even though this was on the generally unpressurized side of the primer solenoid, failures like this could be potentially catastrophic. Over the next few months I'll be exploring alternative methods for a primer installation.

Hope this helps someone else.
 
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It's hard to argue for copper primer line with a picture like that.
I am sure even a stainless line would have broken sooner or later wound up like that.
It's a neat looking loop but it needs to be 90 degrees perpendicular to the line of force tugging on the copper tube.
In other words you want to take advantage of the accordion effect of coiled copper line to get the benefit of a flexible installation.
No primer system or a hose might be best for most builders.

Glad you found that break in time.
 
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