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stripping pcb traces?

Discussion in 'Electronic Repair' started by Ross Matheson, Jul 28, 2003.

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  1. Hi,

    I've been parting out some rather large junked but new-ish photocopier
    SMPS boards, as large as ~ 11"x12" in ali chassis, and eyeing up the
    quality fibreglass PCB itself. Wide traces and groundplane areas, and the
    thought has occurred to me to strip off the actual traces and re-use
    sections of the boards with eyelet tags or turrets for my own projects.

    Any ideas as to how to go about effectively lifting the copper traces to
    get it back to a blank fibreglass board?

    Thanks, RdM
     
  2. Lord Valve

    Lord Valve Guest


    Scour the traces to bare copper with some ScotchBrite.
    Put the board in a tank of etchant.
    LV
     
  3. I don't know how you could possibly re-use it, but scortching it hard
    and fast with a blowtorch will make the traces easy to peel off. The
    real trick will be applying new traces.
     
  4. Lord Valve <> offered the following advice:
    in rec.audio.tubes<>,

    : Ross Matheson wrote:
    :
    : > Hi,
    : >
    : > I've been parting out some rather large junked but new-ish photocopier
    : > SMPS boards, as large as ~ 11"x12" in ali chassis, and eyeing up the
    : > quality fibreglass PCB itself. Wide traces and groundplane areas, and the
    : > thought has occurred to me to strip off the actual traces and re-use
    : > sections of the boards with eyelet tags or turrets for my own projects.
    : >
    : > Any ideas as to how to go about effectively lifting the copper traces to
    : > get it back to a blank fibreglass board?
    : >
    : > Thanks, RdM
    :
    :
    : Scour the traces to bare copper with some ScotchBrite.
    : Put the board in a tank of etchant.
    : LV

    Thanks! I wondered about heat, given experience with unwanted trace lifting,
    but that was mainly on crummy pcbs. Going the whole etchant route occurred
    to me, and I may have to do it, but I just thought I'd ask first. RM.
     
  5. : In article <>,
    :
    : >Hi,
    : >
    : >I've been parting out some rather large junked but new-ish photocopier
    : >SMPS boards, as large as ~ 11"x12" in ali chassis, and eyeing up the
    : >quality fibreglass PCB itself. Wide traces and groundplane areas, and the
    : >thought has occurred to me to strip off the actual traces and re-use
    : >sections of the boards with eyelet tags or turrets for my own projects.
    : >
    : >Any ideas as to how to go about effectively lifting the copper traces to
    : >get it back to a blank fibreglass board?
    : >
    : >Thanks, RdM
    :
    : I don't know how you could possibly re-use it, but scortching it hard
    : and fast with a blowtorch will make the traces easy to peel off. The
    : real trick will be applying new traces.

    Thanks Kevin - I don't want to apply new traces. I want to re-use it with
    inserted rivet-tags (for want of a better word to describe them - I've
    scored a ~500ml jar full of silver-plated double-tag eyelet things) or
    turrets, in my own pattern of holes, afterward. With heat, I'd want enough
    to just loosen the traces (which may be thick enough to "peel") but not
    scorch the board. I may try a heatgun first, and if that fails, use etchant.
    Obviously the heat method would be *far* cheaper:=}) I guess I'll try it.
    Regards, RdM.
     
  6. I used to do it with a knife to break and pull up a trace. Then the entire
    trace could be peeled away from the board.
     
  7. Cheaper? In money perhaps, but not in time. Ferric cloride (or whatever
    it's called in English) is very cheap.

    Best regards,

    Mikkel C. Simonsen
     
  8. : : > Hi,
    : >
    : > I've been parting out some rather large junked but new-ish photocopier
    : > SMPS boards, as large as ~ 11"x12" in ali chassis, and eyeing up the
    : > quality fibreglass PCB itself. Wide traces and groundplane areas, and the
    : > thought has occurred to me to strip off the actual traces and re-use
    : > sections of the boards with eyelet tags or turrets for my own projects.
    : >
    : > Any ideas as to how to go about effectively lifting the copper traces to
    : > get it back to a blank fibreglass board?
    : >
    : > Thanks, RdM
    :
    : I used to do it with a knife to break and pull up a trace. Then the entire
    : trace could be peeled away from the board.

    The mechanical option:=})
    It's a possibility, given the trace thicknesses.
    I've a few of the larger size, and a few more smaller.
    Mostly up until now I had just stripped the HV electros and quality
    resistors, but left the larger ones still screwed to their chassis.
    Tonight I've been unscrewing the larger ones, and realised the quality!
    A trial few passes on a corner with a sharp blade shows that it won't be
    easy or practical on these, though - small bits and fibreglass shavings.
    I haven't gotten out the heat gun yet - I'm still de-soldering parts.

    At least one of these boards I suspect were junked unecessarily.
    Typical output:
    5.1V 3.5A
    12.0V 0.3A
    -12.0V 0.1A
    24.0V 5.0A
    24.0V 3.0A
    24.0V 3.0A
    24.0V 1.0A

    Beautiful construction. Pity I can't re-wind or re-make into something else!
    Salvaging the best of the parts and the pcb seems the best I can do with it.
    Thanks for your input, Robert:)
    RdM
     
  9. As if it matters: a slight error.
    : 24.0V 1.0A
    38.0V 1.0A
    Sorry about the extensive cross-post.
    I think I have enough to go on with now!
    Reports later, if a successful blank pcb point-to-point conversion.
    Thanks to all respondents:- RdM
     
  10. Another option, not quite as cheap as ferric chloride (but a lot less
    messy) is ammonium persulphate. It's what I use when I need to make PC
    boards.

    When using either reagent, the process is greatly accelerated if the
    etchant bath is heated to around 60 Celsius.

    Cheers,
    Fred

    --
    +--------------------------------------------+
    | Music: http://www3.telus.net/dogstarmusic/ |
    | Projects, Vacuum Tubes & other stuff: |
    | http://www.dogstar.dantimax.dk |
    +--------------------------------------------+
     
  11. Mike Berger

    Mike Berger Guest

    These aren't multilayer boards, are they? You'll never get the inside layers

    out.
     

  12. Heat works good. Use your soldering iron to heat a trace and use a blade to
    lift a small bit then grab it with pliers. Working along with the iron and
    pulling on it will get it off with no problems. On larger sections like
    planes a heat gun will work too.
     
  13. :
    : > Thanks Kevin - I don't want to apply new traces. I want to re-use it with
    : > inserted rivet-tags (for want of a better word to describe them - I've
    : > scored a ~500ml jar full of silver-plated double-tag eyelet things) or
    : > turrets, in my own pattern of holes, afterward.
    :
    : How bizarre ....
    :
    : geoff

    As one of Donald Barthelmes characters said,
    "The ane is sometimes inutile to the artist" :)

    They'll be better than this sort of (overpriced) thing, though;
    http://www.tubebuilder.com/ptp boards.html
    extremely cheap/free, customisable, and I get to recycle them:)

    For the investment of a little time, it saves me buying new fibreglass
    boards (although I haven't looked up any prices;- do you know of a good NZ
    supplier for blank fibreglass pcb stock, in case I wanted to start there?)
    and I already have a jar of double tag rivet things - even normal small tag
    strips cost a little, and don't have the flexibility of custom placement.

    I just thought it might be an interesting experiment for point-to-point
    wiring for tube amps - even just for prototyping - and so far, it is:=})

    Ross
     
  14. : > I don't know how you could possibly re-use it, but scortching it hard
    : > and fast with a blowtorch will make the traces easy to peel off. The
    : > real trick will be applying new traces.
    :
    :
    : Heat works good. Use your soldering iron to heat a trace and use a blade to
    : lift a small bit then grab it with pliers. Working along with the iron and
    : pulling on it will get it off with no problems. On larger sections like
    : planes a heat gun will work too.

    So far this technique has worked extremely well, even with a small variable
    20-200W iron. I'm going to get out the 100W iron with the massive tip:=)
    [The only "heat gun" I have is a domestic hairdryer that is a workshop item]
    Thanks for all the suggestions. All I need to do after is get off the green
    lacquer and a bit of writing on the other side. Will try paint stripper;- I
    need to buy a new can though. All in all this looks as though it will work
    out, mainly because so many tracks are really wide high current ones.

    I wouldn't have bothered with a pcb covered in fine traces, multilayer, etc.
    Partly too this was inspired by the earlier point-to-point wiring thread on
    rec.audio.tubes, and mention of turrets and fibreglass boards, etc.

    I probably shouldn't have crossposted this at all, but ta for the x-replies.

    Ross M
     
  15. Geoff Wood

    Geoff Wood Guest

    Any number of electronic supplies companies sell raw PCB (clad) . Why not
    actually make a PCB (easy-peasy) or strip the PCB down to fibreglass with
    etchant, if you are dead set on doing this point-to-point thing.

    The whole concept of ripping traces off ready made ( esp lacquered) PCBs it
    just too bizarre (not to mention time-consuming) to contemplate, for me.
    And even then, you'll end up with fibreglass board with a bunch of unrelated
    holes in it. Do it 'properly' in the first place.

    Or get phenolic tag-strips and do point-to-point wiring like they did
    before PCBs were common.

    geoff
     
  16. : Any number of electronic supplies companies sell raw PCB (clad) . Why not
    : actually make a PCB (easy-peasy) or strip the PCB down to fibreglass with
    : etchant, if you are dead set on doing this point-to-point thing.

    No funds to buy new PCB. Not up to making a PCB now, later sure.
    Stripping with the iron is right here, easy and a small time expenditure.

    : The whole concept of ripping traces off ready made ( esp lacquered) PCBs it
    : just too bizarre (not to mention time-consuming) to contemplate, for me.
    : And even then, you'll end up with fibreglass board with a bunch of unrelated
    : holes in it. Do it 'properly' in the first place.

    Ah, it's just an exploratory one-off, so far, naive as that may seem - it's
    a cheap kick-in to actually beginning prototyping, don't worry about it:)

    : Or get phenolic tag-strips and do point-to-point wiring like they did
    : before PCBs were common.

    I have some - and I have a guillotine that I may be able to chop this with.
    The tags I have are better than the tag-strips. Extra holes are no problem.
    Most of the traces are wide and easy. Still, I understand your reaction:=)
    It's just a no/low-cost trial, utilising the available resources:=})

    : geoff

    Thanks,
    ross
     
  17. Geoff Wood

    Geoff Wood Guest

    How much do you think PCB costs ?

    geoff
     
  18. James Sweet

    James Sweet Guest

    Just get some perfboard and wire it point to point, much easier than trying
    this foolishness.
     
  19. Jimmy

    Jimmy Guest

    May I suggest using a 120 to 240 volt transformer. These are avail at local
    electrical suppliers at current ratings up to several amps if you have he
    money. Then modify the rectifiers to a voltage doubler. This should get you
    very close to your 560 volts with a cap input filter.Get a xformer with taps
    and you can tweak the voltage a bit. I have a couple of 120 to 480 xformers
    with taps. Unfortunately they are rated at 2KVA. may be a little over kill.
     
  20. malcolm

    malcolm Guest

    Ferric Cloride
     
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