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Deconstruction night

  1. Mar 19, 2013 #1
    I am trying to put together a deconstruction night for my students. We will collect all sorts of broken and obsolete equipment and appliances to take apart and see how they work before they are pitched.

    I've already stopped at an appliance shop, music store, and computer store on my way home with mixed results. I'm going to hit up the thrift store on the way home.

    Any other ideas of where to get a variety of old equipment? It would be ideal to go to one place with a myriad of stuff so I don't need to visit a bunch of different places.

    I'm thinking a Rent-A-Center might be a good place to go.
     
  2. jcsd
  3. Mar 19, 2013 #2

    berkeman

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    Be sure to discharge any large capacitors that are in these appliances. They can hold a charge for a surprisingly long time, and the unexpected shock that results can be no fun.

    Good idea for an activity for your students! :smile:
     
  4. Mar 19, 2013 #3

    Any other major safety issues to keep an eye out for?
    Wikipedia says lead-free solder was mandated only as recently as 2006. Should I worry about lead?


    Asbestos
    Lead solder
    TV Vacuum tube
    Misc sharps (glass, metal burs)
     
  5. Mar 19, 2013 #4

    berkeman

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    If you are going to be taking apart any TVs, yes, the CRT is very dangerous. They hold a charge for a crazy long time, and it's potentially lethal. I'm not sure taking about any CRT-based TVs is a good idea. If you could stick with plasma and LCD versions, that would be much safer.
     
  6. Mar 19, 2013 #5

    AlephZero

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    Apart from the resibual charge issue, accidentally breaking a CRT is highly dangerous, because the internal vacuum causes an implosion amd scatters glass splinters around.

    If you want to show kids what is inside a CRT, first seal it up in a STRONG packing box (e.g. the sort of packaging that a new TV woulf be delivered in), break the tube with a hammer blow, then remove the contents wearing suitable protection against cuts (industrial-grade gloves, safety goggles or full face mask, etc).
     
  7. Mar 19, 2013 #6

    AlephZero

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    IMO Lead solder won't be a health hazaerd unless you plan to unsolder components. (Assuming common sense precautions handling any old and dirty equipment, like no eating in the lab etc). The main hazard was from breathing fumes while soldering.
     
  8. Mar 19, 2013 #7

    berkeman

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    Yes, if you are going to be doing any soldering/desoldering, you should have some way to keep the solder smoke and fumes away from the students. At work we have exhaust hoods over our solder stations. When I did a lot of soldering at home, I had one of these portable solder fume extractor/filter units...

    http://tesco.scene7.com/is/image/tesco/270-1026_PI_1000005MN?wid=250&hei=250&$Detail$

    270-1026_PI_1000005MN?wid=250&hei=250&$Detail$.jpg
     
  9. Mar 19, 2013 #8
    We have a fume hood for desoldering. Good idea.

    How do I break the tube with a hammer if its in the box? Have some part to it protrude in a heavy bag.


     
  10. Mar 19, 2013 #9
    Some great ideas here. Now I just need a place to find all this junk.
     
  11. Mar 19, 2013 #10

    berkeman

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    I would strongly recommend against breaking a CRT, even with strong safety precautions. Just show a YouTube video for that demo, please :smile:

    One idea for finding things to take apart might be to talk to your local e-cycling place. They might let you borrow some number of things, if you promise to bring them back all the parts after you take the things apart...
     
  12. Mar 19, 2013 #11
    I was thinking about that. I'm not sure if they would want us to sort stuff as we took it apart.
     
  13. Mar 19, 2013 #12

    Astronuc

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    One could take apart microwaves, and perhaps laser printers or small copiers, radios, CD players, DVD players, old record players, old movie projectors (probably school AV departments still have some), motors, pumps, lectrical switches/relays, or take apart a small car. Cars have lots of parts - engine, transmission, and various electronics in the dashboard/console.
     
  14. Mar 19, 2013 #13

    jim hardy

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    Check you local metal recycler. Ours is full of appliances and yard machines.

    You have a great opportunity to spur creativity.
    1 washing machine motor + 1 car alternator = one heck of a battery charger.

    A small outboard is a good project for a youth. Ones from 1950's & 60's are simple. Look for ones like this:


    I've fixed and given away several to neighborhood teens.. but I make them help so they'll learn.
    I picked up one identical to above just last week. 30 cents a pound, ~ $15.
     
    Last edited by a moderator: Sep 25, 2014
  15. Mar 22, 2013 #14

    Averagesupernova

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    I can't believe no one here knows about the little glass 'tit' on the back of the neck of the CRT. It is underneath the plastic that pushes over the pins. The 'tit' is there to safely allow air into the tube when the TV is determined to be junk. Then there is no real danger if the tube is broken. At least no more danger than breaking a window. When the tube is broken under a high vacuum, there is ALOT of glass moving very quickly. I have shot a CRT from a distance with a .22 rifle. It is pretty violent.
     
  16. Mar 28, 2013 #15
    So far, thrift stores have proven lucrative. I found an old sewing machine without the power cord and a record/8track player. Sewing machine should be pretty cool.

    Any tricks we can do with the amplified phonograph needle before we destroy it? I suppose we could just take it off and touch things that are vibrating.
     
  17. Apr 26, 2013 #16
    Deconstruction begins Monday. I have among other things...

    Microwave,
    sewing maching
    old rack-mount oscillascope
    old rack-mount voltmeter
    Electronics for old pH probe
    Iron
    hair drier
    All sorts of computer components.
     
  18. Apr 26, 2013 #17

    jim hardy

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    Old VCR's are great too - lots of gears and wheels...

    Beware of the big transformer in that microwave. DO NOT let the kids attach a power cord and energize it. Make them remove the high voltage winding (the one with tiny wire).
    Those transformers make ~2500 volts solidly grounded at an amp or two.
    If it gets hold of someone, he can't let go and it IS going to be lethal...
    Each year several people are electrocuted by microwave oven transformers.
    http://www.osha.gov/pls/imis/accidentsearch.accident_detail?id=200030211

    That's the only really dangerous thing I see on your list.

    Have fun !!!
     
  19. May 2, 2013 #18
    Everything went pretty well. It's morphed into a continuous project to fill 5 minutes here and there.
     
  20. May 3, 2013 #19

    Danger

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    If you are continuing your search, I have one more suggestion. My absolute favourite things to ransack are typewriters. They are, to me, the epitome of ingenious engineering. I'm still building things using parts from a 1923 Underwood and I have several other kinds in my "boneyard". Also, an IBM Selectric has an awesome motor with a Gilmer drive.
     
    Last edited: May 3, 2013
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