Component transplants

Discussion in 'General Electronics Chat' started by PackratKing, Jul 15, 2008.

  1. PackratKing

    Thread Starter Well-Known Member

    Jul 13, 2008
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    The main question here, is where does one draw the line salvaging components, with respect to heat degrading their intended function.
    In repair of - say - a dehumidifier power pc that water invaded, and blew the 5+ VR -- TO-220 pkg -- off the board.
    I have an air nozzle cobbled down to a luerlock fitting for hypodermic needles.
    With a heatsink clamped on leads, I use a "melt & blow" technique to liberate components from their original board.
    My main soldering tool for this, is 30w with a 3/16 bevel tip, so dwell on any given connection is way under a second, the burst of air to remove the solder helps to cool the whole shebang on the way out
    This approach has been successful up to now, simply because I am able to see a product go out the door working, and have a fair-to-middling good idea it will continue to work, so I get to keep my pay.
    I keep a number of pc's with all manner of salvageable components for harvest as needed, and a "packrat" collection you could only imagine.
     
    Last edited: Jul 15, 2008
  2. studiot

    AAC Fanatic!

    Nov 9, 2007
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    Whatever works, that's how innovation comes about.

    I hope you have a safe enclosure for all the molten solder you are air blasting about.

    I use an airline to clean out pcs I work on. Mostly salvage is at the whole board/module level. I find that the most useful things to salvage are mechanical bits and pieces like jumpers, stand-offs etc.
     
  3. SgtWookie

    Expert

    Jul 17, 2007
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    Well, you have to figure that your time is worth something.

    Unless you're just bored, sitting around and doing nothing. :rolleyes:

    Sometimes, you can scrounge hard-to-find parts from a defunct board. I picked up a few boards from salvage for a buck each that had some nice 16-bit ADC's and a bunch of opamps all in sockets. I didn't bother with the dozen SMT LED's on each board - mainly because I don't have an SMT de-soldering tool.

    I have a spring-loaded solder sucker that I picked up at Radio Shack. Works pretty well, and the solder winds up inside the tool. Of course, you have to take it apart every 50 de-solderings or so and get all the crud out - but it works, and I'm not creating an environmental disaster site. ;)

    I save the compressed air for when I'm cleaning a board using isopropyl alcohol, getting the dust kitties out of the computer, or running my can crusher.
     
  4. Wendy

    Moderator

    Mar 24, 2008
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    Real men use their hands. :p Little bit of overkill don'tcha think?

    When I was a teen my Dad gave me and my bro an old color TV that was ready for the bone yard. It kept Jim and I in resistors and caps for years, didnt' really have too much use for the tubes. That was about the time I experimented with hand drawn PC boards.
     
  5. SgtWookie

    Expert

    Jul 17, 2007
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    I think my can crusher is pretty cool :)

    Anyway, when I was a teen, I salvaged a lot of stuff. I actually used a good bit of it to fix other stuff. But that was the late 60's, early 70's - and many items are much more specific, and highly integrated compared to back then. Yeah, you might find something useful - but the board would have to be pretty old.
     
  6. PackratKing

    Thread Starter Well-Known Member

    Jul 13, 2008
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    Your can crusher :eek: inspired a use for a pneumatic ram I picked up some years back. From the look, I would guess that it will crush regular tin cans, as well as obliterate soda cans ..............:DWhat is the largest can it will handle, at what operating pressure ?
     
  7. Wendy

    Moderator

    Mar 24, 2008
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    Now look at what you've done Wook. Looks like you and I are in the same time frame, this old TV was an early 60's model, complete with almost round display. We got our hands on it around 72 or so.

    To unsolder old resistors and caps is easy, just tug one them while melting solder. Chips are a lot more problematic, solder wick is expensive. There are a lot of places that have really cheap parts for experminters, but we can't post em unless you ask. Spamming is always an issue on forums like these.
     
  8. SgtWookie

    Expert

    Jul 17, 2007
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    I wouldn't run the one I have at more than 130psi; it's quite old. It does a smashing job on 12oz and 16oz aluminum cans. :D You'll find that many pneumatic rams have a limit of 150psi or even less, right from the factory.

    Since the version I built is a double-ended ram, the upper ram takes away from the maximum pressure that can be applied on the lower ram, due to the reduction in surface area the air pressure can apply force to.

    Lubrication is important. Hydraulic jack oil works quite well. Big orange hardware stores sell it by the gallon. Pnumatic tool oil may contain glycerine, which can cause the seals in older pneumatic cylinders to swell up and seize the piston inside the bore.

    I built a much more simple and utilitarian version using a pneumatic equivalent of a DPDT switch, and some big chunks of aluminum angle. In order to be generally useful, it helps if the ram has an 8" throw, and a bore diameter of 2 1/2 to 4" for good performance.

    If you're using one of the larger diameter cylinders, use plenty of caution. It'll crush your fingers with no qualms.

    I suggest making a "muffler" similar to the one I made; on the lower right side of the main ram. It makes operation much quieter, and reduces the maximum velocity of the ram. I used some thick-walled brass tubing, drilled rows of small holes straight through, and soldered some flat brass stock on either end with a fitting for connecting it up to the tubing. Next go-round I'll use steel tubing; the copper is really too soft.
     
  9. PackratKing

    Thread Starter Well-Known Member

    Jul 13, 2008
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    Thanks for the info.
    The cylinder I have, has a 3" bore, and an adequate stroke. I cobbled some salvaged teflon seals into it. I would use an orifice to feed the ram itself just to slow it down a little. Fullbore feed at 90psi, it really jumps.

    What size air ram do you imagine it would take to squash a 2 liter juicy-juice can, or would this need to get into hydraulics ?
     
    Last edited: Aug 10, 2010
  10. thingmaker3

    Retired Moderator

    May 16, 2005
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    Either there has been an apostrophe run astray, or there's going to be some Volkswagen crushing going on...:eek:

    I sometimes find reclaiming the old components to be a meditative experience. Gives me something better to do than stare out the window and daydream. Doesn't matter if I ever use them or not, the process itself is it's own end.:cool:
     
  11. SgtWookie

    Expert

    Jul 17, 2007
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    OK, so if it has a 3" diameter bore with a single ended ram, then the piston's surface area is pi*radius^2, or roughly 7.07 square inches; at 90 PSI you have 636.3 lbs of force less the drag of the seals/piston/ram. :eek: If you're running 120 PSI, you'll get nearly 850 lbs of force.

    Be careful.

    I think you already have it. If you're not sure, try simulating it by driving over the Juicy-Juice can with a mid-sized Buick. :D

    Now if you have a double-ended ram, you will have a reduced surface area on the piston. You'll have to subtract the square inches of the diameter of the ram that protrudes from the seal from the above calculation of the surface area to get the true surface area, then multiply it by the PSI you're feeding it.

    Hide it from youngsters. Otherwise, at some point while feeding everything on the planet into your smasher that could possibly fit into it, they'll injure themselves.
     
    Last edited: Jul 18, 2008
  12. PackratKing

    Thread Starter Well-Known Member

    Jul 13, 2008
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    :D I think you already have it. If you're not sure, try simulating it by driving over the Juicy-Juice can with a mid-sized Buick. :D

    As soon as I can stop laughing...........point taken.....very good analogy .......I really should stop being lazy and " do the math " first. Anyway, It would be crushing the big can axially if possible, to keep the footprint under the ram as small as possible, since a glancing push could screw things up bigtime.

    Here we go s'more.........would you consider it possible to power an hydraulic ram with air, I have a pair of payloader rams off'n a small JD tractor......................?:rolleyes:
     
  13. SgtWookie

    Expert

    Jul 17, 2007
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    Well, I suppose you could power a hydraulic ram with air, but you'd certainly need to use hydraulic fluid in a lubricator, and you might have a good bit of drag from the extra seals.

    You could also salvage a power steering pump from an auto (like a big Caddy or Chrysler) and drive the pump with an electric motor. :D If a line breaks though, be prepared for a big mess. :eek:
     
  14. PackratKing

    Thread Starter Well-Known Member

    Jul 13, 2008
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    Funny how the topic of this thread went south..........er........my bad !:D

    Oops !:p I did leave one apostrophe out, didn't I :rolleyes: T'would take a rather large compressor to get a beast like my error running !!

    Demolition is definitely very good for the soul. I do it mainly to feed my penchant toward bending [ the hell out of ] physical law, and discovering the limits to "tweaking" circuitry performance. Beats buying stuff to burn up.
     
    Last edited: Jul 18, 2008
  15. SgtWookie

    Expert

    Jul 17, 2007
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    Demolition can be exhilirating ;)

    One of the most exhilirating experiences was to watch a pair of my squadron's Phantoms flying at near-Mach over the aircraft carrier I was standing on simultaneously fire Sidewinder missiles at a parachute flare, and one of them made a direct hit, knocking the flare out! :D This was during a demonstration of power for the SECDEF.

    Building useable items out of salvaged items is certainly an interesting challenge. When I saw a pair of those big beautiful brass pneumatic rams, I just had to have them and make something whimsical out of them ;)

    I got them here:
    http://www.skycraftsurplus.com/
    (No, they don't have any more of them.)
    I suggest you don't go there.
    You don't have enough space to store all the things that you'd buy. :eek:
     
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