Copper for Fuel line.

[288gto]

I purchased a pre made fuel line kit and came to bend it to shape tonight only to put a lovely kink in it on the last bend despite using a proper bending tool!!
To be honest I wasn't too impressed with the quality of it, with one of the ends soldered on wonky.
I really don't want to buy and wreck another one so intend to make my own and solder the correct fittings on, which is what I should have done in the first place.

I have several rolls of 5/16" copper pipe but it doesn't have any kite markings or pressure ratings on it.

My question is, will this be suitable or should I order some?

Thanks in advance,

Simon

[mgcjag]

Hi Simon.....small bore copper can harden and crack under vibration.....id go with Cunifer (copper nickle) which i would have thought your ready made kit was.....cunifer also fir all the brake pipes

[MarekH]

It'll be as good as whatever fittings you make on the ends of it. You'll have to work hard to fail it on account of pressure - the fuel system is very low pressure - even fuel injected cars are only 43psi.

kind regards
Marek

[JagWaugh]

Hi Simon.....small bore copper can harden and crack under vibration.....id go with Cunifer (copper nickle) which i would have thought your ready made kit was.....cunifer also fir all the brake pipes

I would prefer Cunifer as well, amongst other things because it is easier to work than copper.

But lots of the modified and period track cars I see have plain copper tube, sometimes only clipped about 1/3 as much as I would think appropriate, and I've never seen any cracking....yet.

[MarekH]

Until quite recently, 100% of cars in this country (and probably all others) will have used either 6mm or 8mm copper pipe for the lpg and that is at ~8bar. It has never been known to crack. If you have it on a roll then it is soft anyway.

kind regards
Marek

[288gto]

Thanks for the quick replies.
This is what I bought from a major supplier. (bottom pipe) As far as I can tell, it is copper not copper /nickel.
The pain is the other stuff bends perfectly (second pic)
Oh well, you've got me thinking now. I'll make one out of the copper as a practice run and order some copper /nickel on Monday.




E E

[JagWaugh]

According to a google search, BS12449 tubing is suitable for fuel in a marine environment... so it isn't going to be a risk.

I just like Cunifer because it is easier to work, and it isn't quite as red as Copper, so it blends in a little bit more.

[288gto]

Thanks again.

What I have found is that it is much easier to work with a length of pipe that doesn't have pre made ends. Four reasons,
1. You can run it through a straightener.
2. You can start in the middle with the complex curves working outwards and then cut to length and solder on the unions.
3. 7.5m of Kunifer (3 times what you need) plus unions is cheaper than buying g pre made.
4 You have some control over the quality soldering the unions on.

Kunifer now ordered, more so because it looks more in keeping and less steam engine and the roll I bought for the brake pipes is kunifer.

Now back to the new wiring loom that I took woefully inadequate pictures of the original. Await more questions.

[JagWaugh]

3x more Cunifer is cutting it a bit close. Now that you've mentioned it publicly you'll be amazed at how many will pop round when they need a 6" length... as far as I can tell 8x 6" works out to about 12 meters of pipe.

It's not that I'm counting, or even that I mind... but every time I grab my roll of Cunifer it seems to be about 1/3 shorter than the last time I used it. I would suspect that it was thermal contraction, but this can't be the case, as the bits that I actually manage to put on a car don't change length in the same way.