Hi Randall
I have both a copper rich tubing and Cunifer brand tubing, and both are
about the same difficulty to work with using a Sykes Pickavant brake flaring
tool that has a lever action (expensive) as opposed to the wind up flare
tools for a few quid! I have made many replacement pipes for various cars
both clutch and brake, I only use the copper rich for clutches despite it
being labelled as brake pipe. The copper rich tube is easier to bend than
the Cunifer but only slightly, and both are equally easy to kink if you try
to pull too tight a bend, though I would agree it is more likely to kink
steel tube than the copper.
Graham.
----- Original Message -----
From: "Randall" <tr3driver@comcast.net>
To: <triumphs@autox.team.net>
Sent: Saturday, August 05, 2006 10:07 PM
Subject: RE: [TR] Copper brake lines.
>> It was my opinion that copper should not ever be used as brake lines and
>> was
>> in fact DOT illegal.
>
> Common copper tubing, like those used for water or refrigeration lines, is
> definitely not suitable for brake lines.
>
> However, there is a special copper/nickel/iron alloy that has been
> specifically
> developed for brake lines, that seems to be OK. Sometimes known as Cunifer
> (since Cu, Ni and Fe are the symbols for the main alloy elements). It's
> been
> used in other countries for some time now, and seems to work quite well,
> particularly in areas where salt, moisture and sand are found. (The
> tin-plated
> steel we use in the US may rust through if the tin coating is abraded away
> by,
> for example, gravel thrown from a gravel road.) Although Cunifer does
> have some
> "copper" color to it, the color is noticeably lighter than that of pure
> copper;
> more like the color of a new US penny.
>
> But you are quite correct, even Cunifer is not approved by the DOT. I
> expect
> that will change in coming years, but AFAIK it hasn't changed yet.
>
>> Something about the high hydraulic pressure and the copper be easy to be
>> mechanically damaged and cause failures.
>
> I believe the main issue (assuming you use tubing rated for the pressures
> involved), is that copper can work-harden if it is repeatedly flexed, as
> might
> happen from vibration in a car environment. The work-hardening weakens
> the
> tubing, and of course any weakening would be discovered at the worst
> possible
> moment, during a panic stop. The Cunifer alloy reportedly does not suffer
> from
> this problem ... but good design dictates that all brake lines should be
> adequately secured to ensure they don't flex due to vibration.
>
> Another advantage of Cunifer is that it's somewhat softer and easier to
> bend
> into shape without crimping. Probably also easier to form the proper
> flares
> (offering a higher chance of success at making a good one), but I haven't
> tried
> that myself (yet). In retrospect, I wish I had used it the last time I
> had to
> fabricate a brake line.
>
> Randall
>
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