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Unanswered Reseating Bed Magnets

Discussion in 'Troubleshooting' started by PTIschool, Sep 4, 2021.

  1. PTIschool

    PTIschool New Member

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    I have replaced the glass bed on my printer and set the magnets on the bottom of the glass with the 2 part adhesive that is provided with it, but ever since I have done that I am unable to get my bed completely level even with the auto bed leveling. Since auto bed leveling can only compensate for so much with the bed unevenness then I am thinking it is the magnets. When installing the magnets, I didn't have the suggested claps and so I only had weighted objects to place on the bed to push the magnets down. My thinking is that one set of the magnets didn't get pushed down into the adhesive as much as the other set and therefore I have an uneven bed. I tried changing the z offset in both the marlin firmware and the slicer Mattercontrol. Also tried lining up each side of the z axis with a cylindrical object on the bed like I have with previous printers and it looks level but when I go to print, the center and one of the sides is always off and the print either gets pushed to deep into the bed or is too high and doesn't stick. Any help would be great. Thanks.
     
  2. fred3d

    fred3d New Member

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    You may be able to remove the too-thick magnet and the adhesive (2 part means epoxy) if you can identify which one is the problem. Alternatively, remove all three and re-seat them. Weights should have been sufficient to accomplish the task. If you do re-seat the magnets, look for high-temperature epoxy, for obvious reasons.

    When I performed the same task, I placed a layer of food wrap film to prevent any oozing from curing in inappropriate locations. I think I used lead muffin pan ingots I had lying about to ensure good contact.

    Unfortunately, I've not yet had time to put the printer back in service after this effort, so I can't be certain I don't have a problem similar to yours.
     
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  3. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    If you used epoxy it is harder to get them loose. If you used cyanoacrylate then just use a small amount of acetone to free the glue back up.

    Worst case shim the bed under the edges with thin sheets of tape or paper.
     
  4. PTIschool

    PTIschool New Member

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    So I got the magnets off, so now what epoxy do I need to use?
     
  5. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Any good 15 minute epoxy will do the trick (JB Weld, etc.)
    I just used cyanoacrylate on mine and they stay well put.
     
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  6. fred3d

    fred3d New Member

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    Longer cure time epoxies are going to be stronger. 30 minute cure is stronger than 15 minute cure. 60 minute cure epoxy will be even stronger. If you search Amazon for "high temperature epoxy" you'll get a ton of returns, including some JB Weld stuff. Watch out for that, though, as even ordinary JB Weld has metallic particles which will creep over the face of the magnet as it cures.

    I've used this Permatex stuff which has a 2 hour cure time, 500 °F temperature tolerance and isn't too expensive, US$7.00

    [​IMG]
     

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