How to make the sanding discs for my random orbital sander sticky again??

Discussion in 'Boatbuilding' started by magentawave, Jul 19, 2013.

  1. magentawave
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    magentawave Senior Member

    I have a ton of round sanding discs with the sticky back that have lost their stickiness. They still stick to each other on the roll but fly off my sanders pad pretty quick after I start using them. I'll convert to "hook and loop" if I can't get these discs to work but I'm hoping to not have to waste all of them. Does anyone know how I can make the discs sticky again so they won't fly off the pad during use but will still be easy to replace as needed?

    Thanks

    BTW: The sander I'm using is the Porter Cable Random Orbital Sander that looks like a little grinder.
     
  2. Mr Efficiency
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    Mr Efficiency Senior Member

    I'm not familiar with that type of disc, only the velcro type of thing. If you have a spray can of the stuff that stops fan belts slipping, might be worth a try.
     
  3. magentawave
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    magentawave Senior Member

  4. PAR
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    PAR Yacht Designer/Builder

    3M-77 or similar will make the adhesive backed pads stick. I use this all the time and it works as long as you let the paper do it's job and not get it too hot. Hook and loop pads work, but the sander's hook side wears out at an alarming rate, so it'll need to be replaced if you do a good bit of sanding with hook and loop. Hook and loop is more convenient, but having a sander pad die in the middle of a job sucks and nothing will fix it, except a new sander pad.
     
  5. michael pierzga
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    michael pierzga Senior Member

    Long time since Ive use adhesive discs

    Try 3m disc adhesive spray. Hard to find these days.

    or give an electric heat gun a try...sometimes, if the discs aren't to old and dirty, you can bring the adhesive back to life with a little heat.
     
  6. CDK
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    CDK retired engineer

    Rejuvenate the dried out goo with something containing xylol or toluene. That is the stuff all major adhesive brands sell as diluting agent for their rubber cements.
    Wet it, let it flash off for a minute, then put the disc on the pad.

    These are very unhealthy hydrocarbons, read the text on the packaging first!
     
  7. magentawave
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    magentawave Senior Member

    I have acetone and lacquer thinner. Would those work the same as xylol or toluene?


     
  8. magentawave
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    magentawave Senior Member

    Do you need to spray the 3M77 on both surfaces? How easily will the disc come off when I want to replace it?


     
  9. PAR
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    PAR Yacht Designer/Builder

    You can apply it a few different ways, one will make a permanent bond, making disk removal difficult, the other permits disk removal pretty easily. For tough jobs I use the permanent adhesion technique, which require a squirt of thinner to remove. The temporary adhesion technique just peels right off.

    Periodically, you'll clean the sander pad, as it'll build up with stickum, but again some thinner and it's gone.

    Rubber cement also works, but it's not as tough as 3M 77. There's also a 3M 76 "Hi Tack", which tolerates heat better, but is harder to find. I have a can of this stuff and it makes much better one surface bonds.
     
  10. alan white
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    alan white Senior Member

    Why no one has come out with a convertable sanding pad is beyond me. I have two ROs of the same size and one has a smooth surface, the other a hook surface. How about an in-between thin cheap conversion pad that converts a hook/loop to smooth? You could practically make one yourself.
    But no. They like digital readouts and lasers better. This is because the weekend warrior is now running the show. Tools used to be made for professionals.
     
  11. JSL
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    JSL Senior Member

    a wild gamble if you are desperate enough: try (double sided) carpet tape. Exterior grade might work. Regardless, make sure the disc is centered & watch the RPM.... if it comes off it could be a real 'slicer'.
     
  12. PAR
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    PAR Yacht Designer/Builder

    I've seen a Porter Cable product that does just that Alan. It was for their 5" DA. A hook backer on a disk of 16 gauge aluminum plate.
     
  13. CDK
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    CDK retired engineer

    Lacquer thinner is probably cellulose diluent, worth a try. Acetone is good for cleaning the pad.
     
  14. magentawave
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    magentawave Senior Member

    I've wiped the pad with solvent but didn't think to use it to "re-charge" the sticky side of the sand paper. I'll try that when I go up there today or tomorrow and report back.

    Thanks.

     

  15. magentawave
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    magentawave Senior Member

    Paul ("PAR") was right about spraying the old sanding discs with something like 3M-77. I used some spray contact cement similar to 3M-77 but its made by CRC and it worked great! I spray a light mist on the rubber pad on my RO sander and slap the dried out sanding disc on and it stays where its supposed to until I need to replace it. Thanks cuz that suggestion resurrected a few big rolls of 80, 120 and 220 grit discs that I thought were dead!
     
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