PDA

View Full Version : Copper vs Kunifer



Chimeara
08-03-08, 05:28 PM
Having had some time recently to reflect on my builds etc I have been trying to implement further improvements as standard to my chassis/turn key car builds.

One aspect that I have been looking at seriously is braking. Its ok bolting in a big lump of powerful american iron but the subject of halting up said motor when needed is seldom mentioned.

I have therfore implemeted the following.

All future builds will be equiped with drilled & grooved discs and EBC pads fitted as standard.

Having worked on a car recently I also believe that you could have the most powerful calipers and brakes at each wheel but if fluid transfer is a weak link then they will eventually fail or weaken. This brings me to my point. Having worked on a car less than 3 years old (no not one of my builds) I noticed a high level of brake line corrosion.

On closer inspection the lines were made from copper (what I usually use and many other builders have also) and never had any corrosion problems.

Im now thinking though that a preventative method would be to use kunifer brake line, have any of you used this and if so what tech tips have you learned, has it degraded, does it bend the same and is it as easy to flare.

Im sure this will open a mine field and I hope we can be sensible with the replies, simply put its a quality control issue and just one of my product developments as a few extra notes on some brake line could avoid potential problems for future customers and builders in the mid to long term.

I look forward to your replies.

dingocooke
08-03-08, 05:33 PM
Only my opinion Anthony, but personally Id say EBC greens are a downgrade from a good std pad material. Apart from them being a bit wooden in normal use, take a look at an EBC green pad; see how the leading and trailing edges are chamfered away at 30 degress or so on some models of EBC pad to try to replicate OE pad pedal pressures? Only prblem is it reduces effective area by a large amount; seems pretty silly to me.
Re the pipes, copper is most logical to me, and you can polish them up if they go a bit green; Kunifer is OEM on a lot of modern cars though so you pays you chooses!!

wilf
08-03-08, 06:10 PM
Copper work hardens, Kunifer doesn't. Brake lines on production cars are ms, aren't they? No wonder they corrode.

dingocooke
08-03-08, 06:12 PM
most are, some are kunifer, its only copper with 10% nickel anyway; copper is a bit more maleable than kunifer. As for work hardening, they all do.

ldtopham
09-03-08, 08:01 AM
I have used both.

Copper + Easier to flare and bend as it is more maleable, cheaper to buy.
- Work hardens (but then they both do), it will corrode in winter use without light greasing.

Kunifer + Resistance to corrosion
- Cost (negated if you don't have to worry about corrosion), tight radii are quite difficult to achieve without correct bending tools.

I would use kunifer every time now I have tried both;) I had a 12" section of kunifer leaking at a union the night before SVA, as I needed a fix asap I used some copper. After 500miles of winter motoring the kunifer in the same area is as new, the copper nice and furry.

As for brakes I have heard Pagid are good, oe good too. I have EBC pads and discs and they seem ok to me but I haven't had the chance to compare them with the other brands. I don't have a servo and the brakes are more than adequate.

oglyoodoo
09-03-08, 09:19 AM
I posted a reply to a similar thread in 2003.

http://www.cobraclub.com/forum/general-tech-tips-questions/12133-brake-pipe-2.html

There were a few quotes from the Web in it which is a bit of a minefield of conflicting views. Nothing has happened to change my views on the use of plain copper pipe. Certainly I can claim 27 years experience with Kunifer on a regularly used car. I replaced all the pipes in 2003 or thereabouts as they were supposedly guaranteed for 25 years at the time but frankly there was no need to they were as good as new. I still have some of them if anyone wants a look..

Since that posting a friend of mine had a rear brake failure due to a cracked Copper brake pipe on his MGB. Of course this may have been due to inadequate support but IMHO I wouldn't use anything other than Cupro Nickel, Kunifer tubing.

Denis

TINKA
09-03-08, 09:57 AM
Didn't I read a while ago about people not recommending drilled discs as they sometimes give the impression of cracking around where they are drilled :confused: and that the best option is to go for grooved discs instead :D I think Wilf is someone who experienced this and had to replace his front discs. :(

wilf
09-03-08, 12:49 PM
Yes indeed - my discs were showing cracks emanating from the cross drillings, and now I use EBC dimpled and grooved ones. To be fair, my original discs had seen some track day useage.

I think you can get some cross drilled discs that are better than others - after all Porsche seems to think they are OK for their cars. Could be they conutersink them a touch?

dingocooke
09-03-08, 03:05 PM
Re the discs and cracking, its all about materials quality and the finish in the bore of the cross drilling, if the holes are drilled too quickley for production cost reduction, you get a very rough finish and the cracks start form that (stress concentration) the current best practice in competition where the rules limit disc material to steel is discs drilled (not grooved or dimpled). Grooving was found unhelpful in accelerating pad wear in extreme use due to the planing action of the groove on the pads, and the drilling is to allow gas escape from the pad surface without it forming a layer between pad and disc.
Clearly this is only applicable at the extreme of brake use, and even for general track days its a bit academic really; you want good quality discs, calipers and pads suited to the vehicle. But you already knew that :-)

Chimeara
09-03-08, 09:06 PM
Thanks for the comments and info so far guys. I indeed meant the use of the EBC dimpled and grooved discs and not drilled ones.

Think I will go with Kunifer from now on also although it seems like anything there are good and bad points for both.

timddeb
25-08-10, 12:00 PM
Thanks for the comments and info so far guys. I indeed meant the use of the EBC dimpled and grooved discs and not drilled ones.

Think I will go with Kunifer from now on also although it seems like anything there are good and bad points for both.
I have used kunifer on a Landrover for the last 20 years, and show no signs needing replacing. System has twin circuit discs on the front and high pressure master cylinder and braided brake lines

cobracol
25-08-10, 01:00 PM
i am at a loss to understand why copper would corrode after all it has been used in water and gas pipes for years without problem, not noticed any on mine anyway after six years, but i would expect kunifer to be even better

timddeb
25-08-10, 01:33 PM
i am at a loss to understand why copper would corrode after all it has been used in water and gas pipes for years without problem, not noticed any on mine anyway after six years, but i would expect kunifer to be even better
It might be something to do with alkali salts and copper being a good conductor? Lots of copper gas pipes fail when they are in contact with cement.

slogger
25-08-10, 10:08 PM
I had copper and Kunifer on my Cob. Not had a problem with corrosion except where fire extinguishant contacted the copper pipework. The Kunifer was ok. The only problem I have had is that the Kunifer is hard so when I modified my brake system the kunifer would not reform and had to be replaced which required a lot more removal of engine bay items.

Neil O
26-08-10, 06:00 AM
This thread was started in March 08.

I wonder if Antony has any more thoughts this far down the line?

slogger
26-08-10, 04:39 PM
This thread was started in March 08.

I wonder if Antony has any more thoughts this far down the line?

Hey, what the hell. It was late after a particularly harsh day.

In the words of Armstrong and Miller.........Random blood! (RAF pilot sketches)

mylesdw
26-08-10, 08:15 PM
In the words of Armstrong and Miller.........Random blood! (RAF pilot sketches)

Hadn't seen them before, very funny. Loved the one with Geoffrey Palmer.

On the subject of copper pipe - not allowed here in NZ, it would be the equivalent of an IVA fail.

slogger
26-08-10, 09:46 PM
Hadn't seen them before, very funny. Loved the one with Geoffrey Palmer.

On the subject of copper pipe - not allowed here in NZ, it would be the equivalent of an IVA fail.

Just to keep this off topic: Some of the Armstrong & Miller RAF sketches on Youtube. YouTube - Armstrong and Miller RAF Compilation