Working with copper

Discussion in 'Motorized Bicycle General Discussion' started by dracothered, Nov 11, 2012.

  1. dracothered

    dracothered New Member

    Joined:
    Jul 25, 2012
    Messages:
    973
    Likes Received:
    0
    Ok as some of you already know I am going to be making an intake manifold out of copper.

    [​IMG]

    What I am wondering is when I cut and flatten the copper union to make a flange from it should I heat it up to soften the copper or will I be able to work it cold?
     
  2. JonnyR

    JonnyR New Member

    Joined:
    May 13, 2012
    Messages:
    1,203
    Likes Received:
    0
    it will look better if you work it hot but you can work it cold if you have to
     
  3. Tool Maker

    Tool Maker New Member

    Joined:
    Oct 28, 2012
    Messages:
    86
    Likes Received:
    0
    Copper work hardens. Wrought copper fittings are already somewhat hard ffrom the cold work done while making them.

    The good news is copper anneals easily. Grab your torch, and heat one of those couplings up to red hot. Toss the hot fitting in a bucket of water, then you could flatten it with your fingers.

    You can anneal copper repeatedly as you work it. It is not uncommon to have multiple anneal steps when forming things that are deep drawn from copper sheet.

    No need to work the copper while hot for a little project like that.

    B.
     
  4. dracothered

    dracothered New Member

    Joined:
    Jul 25, 2012
    Messages:
    973
    Likes Received:
    0
    So after annealing it and flattening it and cutting out the shape how do I re-harden it?
     
  5. Tool Maker

    Tool Maker New Member

    Joined:
    Oct 28, 2012
    Messages:
    86
    Likes Received:
    0
    You can't.

    If you want the end product hard, beat it in to submission as-is. The only way to harden copper is to work harden it. Added cold work will make that coupling even harder.

    B.
     
  6. dracothered

    dracothered New Member

    Joined:
    Jul 25, 2012
    Messages:
    973
    Likes Received:
    0
    Ok do you think it will work harden enough when I flatten it out so I can make the flange? What about thickness, should I try to bend a lip around the outside edge to stiffen it?
     
  7. tooljunkie

    tooljunkie Member

    Joined:
    Apr 4, 2012
    Messages:
    663
    Likes Received:
    0
    i would try to locate some copper sheet,and make a die set of sorts,pressing it in both directions to harden it.unfortunately soldering it together will soften it again.
    i would look at making a brass flange for it and soldering the copper pipe to it.
     
  8. silverbear

    silverbear The Boy Who Never Grew Up

    Joined:
    Jul 9, 2009
    Messages:
    8,188
    Likes Received:
    10
    I'm no expert with this, but thought I'd relate a negative experience I had while trying to make a copper exhaust pipe. (I thought it would look cool.) I soldered my fittings together with silver solder and it did look good! Boy, was I please.
    I fired up the engine and liked the sound, too. Got about thirty feet down the drive and the pieces started coming apart, beginning with whatever was closest to the engine. The exhaust heat melted the solder. Maybe there's a way around this or a better solder to use, but my thinking is you might be better off using something other than copper. I hope you can make it work.
    SB
     
  9. Tool Maker

    Tool Maker New Member

    Joined:
    Oct 28, 2012
    Messages:
    86
    Likes Received:
    0
    I have to agree that copper would be a bad choice for a mechanical part like a flange. Even with some work hardening it would distort badly as the gasket compresses.

    I would use some 3/16" or 1/4" brass for the flanges as someone else already stated. Somehow I missed the intention to make flanges from the tube, I was picturing an oval section for an intake port match.

    You can also solder copper to steel, if you happen to have a steel flange that matches your engine or carburetor.

    B.
     
  10. dracothered

    dracothered New Member

    Joined:
    Jul 25, 2012
    Messages:
    973
    Likes Received:
    0
    Really it will work with the steel as I have some big washers I bought earlier for this and then was told I can't silver solder copper to steel. This would make it easier to make the flanges as I will not have to drill a large center hole in the flange.
     
  11. 2door

    2door Moderator
    Staff Member

    Joined:
    Sep 15, 2008
    Messages:
    16,304
    Likes Received:
    29
    You'll need to get some practice before you attempt to silver solder copper to steel. It can be done, is done everyday, but it's not a job for someone without experience. Before you jump into it you might want to check the prices on a roll of silver solder. It might cost you more than the rest of your bike.

    When we're talking about 'silver solder' we're not referring to the stuff on the hardware store shelves in the plumbing section. Just because it's silver in color, most solder is, doesn't mean it is the type used to get a good solid solder joint that will be needed to keep your carburetor from vibrating off.

    My advice would be to befriend an air conditioning mechanic and have him do the work for you. A/C guys silver solder copper pipe/tubing to steel mufflers, driers and compressors. It requires high heat, preferably oxy/act or a turbo torch. You won't get it to flow with a little butane torch. It also needs a special flux available where silver solder is sold.

    Tom
     
  12. dracothered

    dracothered New Member

    Joined:
    Jul 25, 2012
    Messages:
    973
    Likes Received:
    0
    The silver solder I picked up comes in a stick and of course what did I forget when I was getting it, the flux. I have a oxy/map torch which I believe will get hot enough.
     
  13. 2door

    2door Moderator
    Staff Member

    Joined:
    Sep 15, 2008
    Messages:
    16,304
    Likes Received:
    29
    Here's a photo of the product used in the air conditioning trade.

    Tom
     

    Attached Files:

  14. tooljunkie

    tooljunkie Member

    Joined:
    Apr 4, 2012
    Messages:
    663
    Likes Received:
    0
    silver solder is pure (or very close to it)and requires a special flux.and usually more heat than propane.
    Mapp gas is hot enough for this application methinks.
    regular solder is tin and lead in varying degrees depending on its intended use.
    silver solder is frequently used in the process of joining bandsaw blades made of high carbon steel.

    if your plan is to use a washer,sand off the plating before trying to solder.
     
    #14 tooljunkie, Nov 12, 2012
    Last edited: Nov 12, 2012
  15. silverbear

    silverbear The Boy Who Never Grew Up

    Joined:
    Jul 9, 2009
    Messages:
    8,188
    Likes Received:
    10
    I'm still wondering if the heat from the engine exhaust will turn the silver solder molten. It did mine and in pretty short order. I was using expensive silver solder with the appropriate flus made for it. It soldered the copper fittings together beautifully. The problem was too much heat from the exhaust manifold once I rode the bike. And that was just a HF 79cc Greyhound engine.
    SB
     
  16. 2door

    2door Moderator
    Staff Member

    Joined:
    Sep 15, 2008
    Messages:
    16,304
    Likes Received:
    29
    12 to 1400 degree melting point. I doubt that your exhaust gets anywhere near that hot, SilverBear.

    I'd need to see what solder you used to tell you what went wrong with your pipe. My guess is that it was not actually 'silver solder' which is technically called an brazing alloy, but some less expensive subsitute marketed under the name, silver solder.

    There is a lot of misunderstanding regarding soldering/welding/brazing. There are terms used that does not always accurately describe the product.
    The type I pictured above would not be effected by any exhaust system unless maybe you're talking about the space shuttle. :)

    Tom
     
  17. silverbear

    silverbear The Boy Who Never Grew Up

    Joined:
    Jul 9, 2009
    Messages:
    8,188
    Likes Received:
    10
    Aha! You are no doubt right, Tom. That makes sense. The silver solder is what I purchased from my local Ace hardware. For what I paid for it, it should have been pure silver. That's good. I wanted to see this project work and not end up in pieces as mine was.
    SB
     
  18. dracothered

    dracothered New Member

    Joined:
    Jul 25, 2012
    Messages:
    973
    Likes Received:
    0
    I'm building an intake at this time, not the exhaust side. So I don't think there will be the same heat issues that the exhaust side has to deal with, but I could be wrong.
     
  19. silverbear

    silverbear The Boy Who Never Grew Up

    Joined:
    Jul 9, 2009
    Messages:
    8,188
    Likes Received:
    10
    Jeez,
    I must be going senile. Intake and exhaust??? Yeah, there's a slight difference! Think I'll go to bed and start over.
    SB
     
  20. dracothered

    dracothered New Member

    Joined:
    Jul 25, 2012
    Messages:
    973
    Likes Received:
    0
    Don't worry SB, I have my days too when I keep on saying the same thing over and over and then a split second later I realize duh that's not it.... laff
     

Share This Page