Exhaust copper tubing as exhaust?

Discussion in '2-Stroke Engines' started by mechanicojoe, Jan 17, 2009.

  1. mechanicojoe

    mechanicojoe Member

    so im rebuilding my chopper to a mini chopper and not a bike:whistling:
    I think most people have seen the thunder pipes barry on ebay makes.
    well i dont have money right now but i got copper tubing and joints.
    i was thinking of just cutting a spare muffler where it joines the engine to the muffler.
    i would then just put some peices on and sna, flux, and then soldier. but people have said that it will melt the soldier and pipe really fast but they where talking about cars. whats the temp that the engine puts out at 80ccs?
    i would then spray it with high temp exhaust paint and then put on exhaust wrap.
    any ideas?

  2. fetor56

    fetor56 Guest

    I can't see any real problems with your idea...infact it's a good idea.The temperatures the exhaust reaches for solder would be fine,i would just be concerned with the strength of solder.
    Better to silver solder,or even better to braze........i'm a big brazing fan.
  3. MotorMac

    MotorMac Member


    It should work, as long as theres no joints too close to the actual exhaust outlet. It takes about 650 degrees F to melt solder and I do not think it gets that hot on the exhaust.Make sure you use plumbers solder and not electronics solder.
    You can do a test by cutting a piece of solder and placing it on top of a section of the pipe you have on now , start up ,warm up and see if it melts, it shouldnt.
    Last edited: Jan 17, 2009
  4. fetor56

    fetor56 Guest

    BTW....it's a good idea with any joins to put an inner sleeve between the two....strenghten things up.
  5. MotorMac

    MotorMac Member

    Will brazing work with copper??
  6. HoughMade

    HoughMade Guest

    I guess it could, but the problem I ran into with relatively thin brass and copper (like pipe as oposed to solid plate) is that the brazing flame can burn through before you get good flow of the brazing rod.
  7. fetor56

    fetor56 Guest

    To tell u the truith i'm NOT 100% sure myself,but with anything like this u DON'T take someones word on something.....u experiment around with offcuts & see how successful u are.
    If your not happy then it's always Plan B.
  8. machiasmort

    machiasmort Active Member

    Could always leave the first part steel and solder or compression fit copper after.
  9. Flapdoodle

    Flapdoodle Member

    Years ago I brazed a copper exhaust system on a Corvette for a guy. It was not difficult.

    I have a copper exhaust on a home-made outboard here:
  10. terrence

    terrence Member

    I agree good idea. We devised a copper exhaust on a riding mower. Exhaust held up great but the hi temp paint burnt off after about the 5th use. I think the exhaust wrap would be a winner though.
  11. MotorMac

    MotorMac Member

    Wow that looks like an interesting little project, did it ever work well to your expectations?
  12. HoughMade

    HoughMade Guest

    You'll have inspired me. I think a polished copper exhaust may find its way onto the HoughMade '71'
  13. I did copper tubing and fittings off my header to my expansion chamber. It needs to be brazed or silver soldered. The guy that did mune didnt weld very good so I wrapped it in header wrap. Hard copper works fine, thicker walled than soft copper....
  14. Flapdoodle

    Flapdoodle Member

    I assume you mean the motor, thanks. Yes, it is a delight to use at only 9# and just a gentle purr for sound. The copper is not brazed. I used SS sheetmetal screws and can't really see any leaks. I was surprised that I can put my hand on the lower part of the exhaust while the upper part gets hot enough to discolor the copper.
  15. mikaleno

    mikaleno Member

    Yes, I was thinking about using copper for an exhaust too. Sure would be easier to cut, bend and braise this stuff. I wonder if it could be chrome plated?
  16. Flapdoodle

    Flapdoodle Member

    Anneal the copper with a propane torch, pack it solid with sand and bend around something round, like a smooth wood log.

    Copper used to be used to plate steel car bumpers before chrome plating.

    On my outboard exhaust, it tarnished rather quickly, but light rubbing with 000 steel wool makes it bright again.
  17. machiasmort

    machiasmort Active Member

    Sorry for the correction. I meant to say use a compression fitting between copper and steel flange to motor. I thought about making an additional muffler for my HT. DO NOT breath the fumes if you heat copper!!! There's a reason why they don't make pipes for smoking tabacoo out of Copper!!!!
  18. ok ive been playing with the idea of making a completley copper expansion chamber and exhaust. however it seems as if that's not going to happen because i would have to sell my first born for some copper sheet. but if your just going to make and exhaust manifold with no expansion chamber then you could use home depot copper with out any issues. you would have to treat it like any other metal tubing when bending however, and you would need to get a piece of copper strap to make the flange to bolt up to the head.

    also you could not use solder, solder even the high temp stuff would eventually come apart on a 2 stroke manifold. higher performance 2 stroke exhausts can get to 500c and above. that's enough to melt pretty much any solder. but you can get brazing rod from the home depot and fill with that and be ok. but really ideally you want to actually braze weld, which with copper is probably out of most peoples skill range so filler rod will be fine. you also don't have to use flux if you dont want to.

    also i don't know what kind of crack you people have been getting into but why on earth would you want to paint or plate copper? its already a corrosion resistant material that gets a very very nice looking patina to it once its been heated up and cooled and exposed to air for a long time. which would look pretty good on a vintage looker bike.
    you can also rapidly speed up the patina and coloration by spraying copper down with a rough mix of

    3 ounce Copper Sulfate
    1.34 fluid ounces of Tech grade Ammonia
    6lbs of Ammonium Sulfate
    and 6.5 gallons of water.

    spray it on in a fine mist for a few coats letting the mixture dry between coats.
  19. fastboy9

    fastboy9 Member

    I was using a copper header pipe for about 3 months or so. Ghost0 on here used plumbers solder and it melted off after a few weeks, so I brazed mine and had no problems with it what so ever!

  20. Mountainman

    Mountainman Active Member

    think this will work
    weak point may be
    although the solder may not melt
    at a certain spot way before melting
    I think that it does lose strenth

    brazing is pretty darn strong as we know
    in welding class years ago we didn't braz copper - why - not sure - maybe just didn't get around to it ?

    repair and ride those things
    Last edited: Jan 19, 2009