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How to weld aluminum foil?

  1. Jan 21, 2010 #1
    Hello, I'm Mike from over on the EE board, and I'm looking for good advice regarding welding aluminum foil. I had a vendor that used to do so inside his capacitors and he even bonded the foil to solderable leads. Any ideas are certainly welcome,

    Best Regards All,

    Mike
     
  2. jcsd
  3. Jan 22, 2010 #2
  4. Jan 22, 2010 #3

    Mech_Engineer

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    Laser welding might also be an option, I've had very small parts made using laser welding processes. I assume they can probably tune the power for thin foils as well as micromachining.
     
  5. Jan 22, 2010 #4

    Q_Goest

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  6. Feb 3, 2010 #5
    I'm not too sure about the other methods in this thread, but I am fairly sure you can do this chemically at a low cost.
    I had an example done way back in my highschool days. It involved a compound (flux and weld material) placed in the seem of two pieces of foil. THe foil was lowered into a container of fuild and an electrical charge put though it. THe electricity bonded the foil together.

    Jim
     
  7. Feb 4, 2010 #6

    FredGarvin

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    I would have gone with either EB weld or brazing.

    Jim, do you remember any of the particulars of the process you mentioned?
     
  8. Feb 4, 2010 #7
    No, unfortunately it was a long time ago in a pilot program in highschool. But I did assist with the actual welding of foil.

    I remember the unit used was also used on making ciurcut boards. (the old way, where you used soldier sheets and placed them on green board.) The tracing compond was the same used to bond the foil to the greenboard. After exposing the compound to the electricity you would pull the green board and wash it off. The non bonded material left over from the sheet would flake off, leaving your cuircut pathways on the board.

    I know the componds and chemicals that made up the dip and the bonding agent were simple and readily available in 1990.

    Hopefully this helps.
    Jim
     
  9. Feb 4, 2010 #8
    I don't know your application or the thickness of your foil. But if it is standard kitchen foil, I would use the heavy duty stuff. (the thicker the better)

    Also I would look into polymers to bond the foil sheets together.
    If you are passing an electrical current through it and are concerned with the conductivity of the polymer, you could buy conductive glues, or put copper power into the polymer.

    I am working on a HD antenna at home and using a thin aluminum mesh (almost foil thin) I have bonded it to a aluminum frame with Aluminum powder in the bonding glue to keep the whole unit conductive to electronic signal passage.
     
  10. Feb 4, 2010 #9
    I also remember seeing thin sheet metals (back in the 1930's) being welded together using a powder burn process where you used a flux (plumbing pipe flux) mixed with bonding metal powder (same metal as the sheets) and magnesium powder.

    The mix would have to be experimented with to get it right. (not to burn too hot or too cold)
    But you use the paste between the seems of the sheet metal and ignite it with a torch. The magnesium powder flares and burns melting the powdered metal and "welding" the two sheets together. (it is not a clean weld but it works)

    You just have to be very careful. a little magnesium goes a long way and can easily hurt you when it flares. (remember grade 12 science?)

    Jim
     
  11. Feb 4, 2010 #10
    You could also experiment with soldering the foil sheets together. I would use a propane torch and cover the sheet seems with flux (extending it out from the seem a bit) and melt solder over the seem and drop the solder onto the seem. The residual heat from the liquid solder should bond the foil together. You’d have to adjust the drop height to get the temperature of the liquid soldier drop correct for bonding. But it should work. You could also experiment with tipping the torch flame to pre heat the foil a bit.
     
  12. Feb 4, 2010 #11

    Gokul43201

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    It's a little tricky, but I've been able to spot-weld thin aluminum sheet stock. It takes a high current with a short zap-time.

    If you're skilled with brazing, you could try to give that a shot, but it might be a little hard to not melt the foil.

    Something like this might work nicely: http://www.solder-it.com/shop/category.aspx?catid=6

    Or this: http://durafix.com/
     
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