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[Bullet Whisperer]

'Copper Disulphide is what is emitted when copper bearing ore is heated to extract the copper, not when copper pipe is heated ..... ' I can't argue with that, because I am not, and never claimed to be a scientist. I posted a link to where using copper pipe for exhausts was being discussed and it came from there, but there are lots of others who appear to believe copper for exhaust pipes may be illegal. Best thing to do is stick a copper exhaust pipe on and find out for certain, whether it is legal or not, rather than try and argue the toss with me over it. Cheers, Paul.

[Scalyback]

[center]Subject exhausted, it's a wrap?



Oh, ok then, but I just had to get that in. The swiss A350 condor exhaust were covere with aluminium coating or paint to stop them being so reflective. I wonder how that went environmentally wise?





Swiss army bike for real mountains!

[Adrian]

Not sure about aluminium, ISRTC from school chemistry days that aluminium very quickly forms an oxide layer, I don't remember being taught anything about noxious fumes from hot but not molten metal. Likewise with copper, if it has been **purified** by refining or electroplating, I don't see where the sulphur would come from to to produce the sulphides. Back to school chemistry again, if you heat copper in air it oxides, ie it absorbs oxygen to form a layer of copper oxide. As a point of interest the BSA WD B40 had a matt chrome exhaust in order not to attract Warsaw-pact attention on the potential battlefield.



A.

[PeteF]

I've wrapped trials pipes before and the wrapping does, of course, get hot. Surely it's a question of the thermal conductivity of the material that stops it burning clothing, skin etc. Yes, if you hold the hot wrapping for long enough you'll get burned, but you'll be able to hold it longer if its wrapped. It certainly stopped me ruining waterproof trousers on a Greeves which had a very high header pipe.

[Bullet Whisperer]

I've got it! The answer to all of this has been staring us in the face all along!! Fit a [possibly illegal] copper exhaust system and cover it from end to end in exhaust wrap - no one will ever know, Doh!!!

[Revband]

WOW, What a great idea all that heat kept in nicely. you could perhaps melt the copper pipe at the same time as the exhaust valve.

[Gwilly]

I think you may find that an exhaust header constructed of copper
may last for a matter of weeks or months at best.

Products of the COMPLETE combustion of hydrocarbons i.e. petroleum or Lpg gas
includes a large amount of water along with carbon dioxide, nitrogen oxide (NOx) and sulphur dioxide (SOx) to name just some..

Unfortunately these gases will readily dissolve in water to form weak acids which will eat through the copper in short order..

Witness what happens when a "diy" bod uses copper pipe instead of plastic on a condense drain from a condensing boiler..

Also wonder what would be the effect of exhaust port temperature on the strength of the copper bends? Given the annealing and softening of the copper..

Perhaps maybe a steel pipe which is copper plated would polish up rather nicely.

[jefrs]

Revband, no worries but I think you misunderstand the term "thermal equilibrium" it does not mean equal temperature, it means a thermal gradient.

If you heat one end of a rod the other gets hotter and hotter until it stops at some lower temperature, at thermal equilibrium, due to cooling. This gives us 'thermal conductivity' which depends on the material and temperature of the hot end. Asbestos is a good insulator but it's not that good, it's more of a fire-proof material, if one side is very, very hot, the other side of the tape with be very hot. It may well protect your boot and trousers but you don't want to grab it up by the exhaust port.



When an exhaust is cherry red it is too hot but that colour means it is at or around 1000°C which will melt aluminium (660°C) and soften if not melt copper (1085°C). Steel goes runny toffee around 1300°C to 1500°C for welding. Fortunately for the copper sealing ring, the head has cooling fins for good reason. Which kinda means we're stuck with good old steel.

[Revband]

Jeffrs, you are just far too patronizing and tend to treat everyone else like an idiot, where you by chance a school teacher?, most of the contributors on here are sensible well educated people and you just don't give them credit. You said yourself that people don't understand you, perhaps you should try and work out why that is. It will probably be best if we just ignore each others posts.

[Revband]

Just one thing that was missed off

"Noun 1 thermal equilibrium - a state in which all parts of a system are at the same temperature"