Connect with us

Dry Film Adhesive?

Discussion in 'Troubleshooting and Repair' started by bbotts77, Sep 7, 2012.

  1. bbotts77

    bbotts77

    5
    0
    Sep 7, 2012
    I was desoldering while tired and ripped a solder pad right off of a board. So, I was looking at how to repair the board and I came across a youtube video where they use a dry film adhesive.:confused: I was hoping one of you could tell me what this product actually is that the tech is using to affix the pad to the board.

    If you don't know what this stuff is, could you please recommend a different product for reattaching the pad to the board. It is a small rectangular pad that a 20-pin IC would be soldered to.

    Thanks in advance,
    Ben
     
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,174
    2,690
    Jan 21, 2010
    You may be best repairing it with a strand of wire. Something like wire wrap wire is often used, but the cut off lead from a small resistor would also work fine.

    The major thing is to ensure you have connectivity to the trace that the pad was connected to.
     
  3. markm6164

    markm6164

    118
    0
    Jan 22, 2012
    I often wonder what everyone does about lifted pads, not damaged pads. I have seen many pads where people pull the pad when desoldering due to lack of heat. The pad is still intact but no longer secured to the board.
     
  4. CocaCola

    CocaCola

    3,635
    4
    Apr 7, 2012
    Don't life the pads in the first place ;)

    If I'm repairing a lifted pad like this I generally just cut it off and bend the leg of the component towards the associated trace and make the connection there, and than hit the component with a dab of hot glue or epoxy to keep it stable so it doesn't rip the trace connection...

    You could glue the pad back down with a high temp adhesive there are many that should tolerate a single soldering of the joint...
     
  5. Jotto

    Jotto

    120
    0
    Aug 24, 2012
    Applying too much heat causes the pad to lift. I don't bother gluing unless its a dual trace board or it can't handle the current because of trace size, I also use a piece of wire through the hole, doesn't have to be large in diameter, just there to help hold the pad in place when soldering. There are repair kits out there also, but they aren't cheap.

    As mentioned by others, there are many ways to fix them.

    Some people end up messing the trace up during desoldering. If the component is being difficult to remove, cut out the component and remove one lead at a time. I also keep a pen vise drill if its giving me a hard time removing the solder, doing this you must be careful, use a small bit first then increase the size, do no go to the correct size of the hole.

    A good tool to have is a solder sucker, but I would recommend for the person that can't afford a good desoldering station to purchase the one Radio Shack sells, it has a red bulb and is also a heated tip. I used this for many years and I was running a repair business. Buy all the tips they have, and every time you there. You will go through the tips as time goes by, but its cheap and will last many years.

    And when you get old, get a jewlers loupe, its a great help for seeing the print on SMD compoents.
     
    Last edited: Sep 7, 2012
  6. bbotts77

    bbotts77

    5
    0
    Sep 7, 2012
    Hey guys. Thanks for the responses. Unfortunately, I do need to glue the pad back down or spend $200 on a repair kit. This is a surface mount pad and the trace goes under the chip. I suppose I could just solder the pad back to the trace and rely on the connections of the other legs to the board to hold the pad down. I just don't like that option. I really want to glue the pad down. So, what I'm looking for is suggestions for a good high-temp adhesive to hold the pad down.

    Thanks.
     
  7. CocaCola

    CocaCola

    3,635
    4
    Apr 7, 2012
    As I suggested get a high temp adhesive... Since in reality once the rest of the chip is in place if the glue fails nothing will go wrong you could even use superglue or any generic epoxy to hold the pad in place long enough to solder... If you are worried about the connection, trace the track back to another point and use a small wire to jumper from the IC to that common point...

    If you want a product recommendation Permabond 820, it's costly but the datasheet says it can handle soldering temps for a short period of time if not stressed...
     
  8. bbotts77

    bbotts77

    5
    0
    Sep 7, 2012
    Thank you very much. I'd much rather spend $50 on an ounce of glue, than $200 on a repair kit that I probably won't use again or $1000 on a new board. Thanks again. I'll let you guys know how it turns out.
     
  9. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,174
    2,690
    Jan 21, 2010
    What's your address, I'll send you a resistor free(!) and you can use the wire from that to bridge the connections.

    Oh, then send be $50 that you were going to spend on glue.
     
  10. bbotts77

    bbotts77

    5
    0
    Sep 7, 2012
    I appreciate your offer, Steve. But, there isn't much clearance under the DAC for a resistor lead and I feel much more comfortable gluing the pad down and soldering it back to the trace.

    I'm actually going to do some more searching on digikey for high-temp adhesives. I can probably find something at a better price than $50/oz.
     
  11. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,174
    2,690
    Jan 21, 2010
    I was assuming it was through-hole. Perhaps you can show us a picture?

    If the trace leads under the chip, and it is unbroken, then just solder to it (carefully)/

    If it's broken, then you may have to route a wire somewhere.

    If the trace leads out from the chip, then again, a piece of wire is appropriate.

    How are you going to solder this back into place? If you're reflowing and the glue means the trace is a little more proud of the surface then you'll have to be sure you make good solder connections to nearby pins. In the worst case you may need to bend that pin up and solder it individually after doing the others.
     
  12. bbotts77

    bbotts77

    5
    0
    Sep 7, 2012
    Unfortunately, no. It's surface-mount. I'll try to get a picture. It's pretty tiny though and I don't have a decent camera maybe I can get a good one through my jewelers' loop.
    The trace is still in pretty good shape. I was able to scrape the solder masking off of a little bit of the trace and the pad without damaging either, so I should be able to solder them back together with no problems at all.
    I haven't traced the trace to see where it leads. But, a wire from the leg to another part of that trace might be an option.
    I have also scraped away the old adhesive from the board, so there should be 1 or 2 mil worth of space for the adhesive between the pad and board. I've done quite a bit of research on this repair. The missing link is the adhesive. I plan on soldering that pin last, so I can get the chip in place and tacked down before I hit that pad. That way I don't have to apply too much heat for too long to that leg and pad.

    Thanks for all of your suggestions and the product recommendation. I'll try to get a pic of the current mess. I'll also keep you guys up to date on my progress/follies with this repair.
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-