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How do you fix torn/worn solder pads?

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  • #16
    We use these at work when we have to but very expensive.
    http://www.circuitmedic.com/

    Most pcb's for musical equipment amplifiers are junk. Good boards cost good money and we can't have that can we? Best bet is "get in get out" solder as fast as you can and do not get the board hotter than absolutely necessary.

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    • #17
      Originally posted by mozz View Post
      We use these at work when we have to but very expensive.
      http://www.circuitmedic.com/

      Most pcb's for musical equipment amplifiers are junk. Good boards cost good money and we can't have that can we? Best bet is "get in get out" solder as fast as you can and do not get the board hotter than absolutely necessary.
      That has to be one of the biggest rip off's I've seen in a long time. $4.95 for 5 x isopropyl alcohol swabs ( cost about $0.10).

      36in of 2 x 5 thou copper wire $39.95! Seriously!! Tinned copper will do the same job equally well.
      Experience is something you get, just after you really needed it.

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      • #18
        I just have this image of Juan mixing two part epoxy, but just enough for a toothpick tips worth. Dude's got a trick for everything, I am sure he has one for this too.

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        • #19
          Originally posted by ric View Post
          Is there a type/ brand of "clear"/ heat tolerant epoxy that you people use?

          The brand I use (Devcon) sets somewhat amber and I've never thought of it as particularly heat resistant, though I guess that was an assumption that I've never needed to test.

          I lifted a trace and would like use this info, but want to use the right stuff.
          "Somewhat amber" is clear enough.
          I meant "pure epoxy" instead of the powdered aluminum filled one or white or black which carry pigments.

          It will lose strength while solder hot , exact same as original Epoxy PCB material Epoxy, of course, but unless you juggle the component lead around while it´s at peak temperature or push through an unopened hole it will reasonably hold.
          In an nutshell, what made the *original* pad or track lift.

          If the hole is clean, surface is clean, you solder fast and not subject it to mechanical effort while soldering, it will be practically "as good as new".

          Cyanoacrilate? .... maybe there is some NASA quality version out there, dunno, but standard one is way weaker than Epoxy, specially when hot.

          There must be some reason that speaker voice coil wire is routinely bonded to form with Epoxy and not with CA.

          And that copperclad board material is bonded by curing under pressure a copper sheet and Epoxy or Phenolic Rosin impregnated paper/fiberglass sheet.

          I know no PCB material made by glueing copper to insulating base using CA.
          Juan Manuel Fahey

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          • #20
            I use all kinds of Cyanoacylate for work-holding in the lathe and miller. Strong enough when cold but easily separated when warmed up. I have my doubts that it would hold a pad where a component gets warm. I never tried it on a regular solder pad because of the heat of soldering (especially unleaded) breaking it down.

            Whenever a pad has lifted, after repair I clean away the flux residue and use UV epoxy over the top as extra security. It flows really well and strengthens the joint area.

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            • #21
              Sounds like if the boards are laminated with epoxy, that's the stuff to use. Now I see what Juan meant by "clear" epoxy. The question now becomes: what is the UV epoxy Mick mentions? Ultra violet light stabilized?

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              • #22
                The UV cure epoxy is polymerized with a UV torch and is really tough. I have some used for tying fishing flies and it's available in different viscosities. You can use regular epoxy, though this stuff is water-clear so in the future you can see what's going on underneath. I just happen to have this to hand as I use it for guitar repairs.

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                • #23
                  Originally posted by Mick Bailey View Post
                  The UV cure epoxy is polymerized with a UV torch and is really tough. I have some used for tying fishing flies and it's available in different viscosities. You can use regular epoxy, though this stuff is water-clear so in the future you can see what's going on underneath. I just happen to have this to hand as I use it for guitar repairs.
                  Thanks, Mick

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                  • #24
                    Many UV curing adhesives are actually urethane based with a temperature range up to only 150°C. For the purpose here I would only buy stuff with a data sheet explicitely specifying epoxy and/or a temperature range up to 200°C or more.
                    - Own Opinions Only -

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