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Thread: MDF and dog holes?

  1. #1
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    MDF and dog holes?

    Thoughts?
    I'm concerned about the holes getting sloppy over time . I'm going with 2 layers of 3/4" along with one of 1/2", topped with an 1/8th or 1/4 ' hardboard. Is this a legitimate concern? Has the sleeve/bushing idea ever been addressed? Or if adding an interior layer of ply would be of benefit? I already have the mdf, so changing over to solid wood is out for now.

    Just wanting to insure I can get all the reasonably expected life out of them...Thanks in advance
    The perception of perfection is perfectly clear to everyone else

  2. #2
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    4 layers of 3/4" MDF, no hardboard top, going on 8 years of almost daily use. I flooded all sides of the top with BLO and have refreshed the paste wax every year or so.

    Click image for larger version. 

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    I use holddowns and dogs of various kinds, I use the dog holes for accessories like a lamp and a magnifier but, primarily for holding material for hand planing as well as power tool work. Obviously the 3" thickness gives me some advantage but, you could make the rows where the dog holes will go 4 layers and leave the bulk of the top at 2 layers.
    Last edited by glenn bradley; 12-03-2014 at 01:35 PM.
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  3. #3
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    I would flood the holes with thin CA glue to toughen them up. It will soak right in and make the surrounding fibers stronger.

  4. #4
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    Thanks guys, great ideas...eases my mind
    The perception of perfection is perfectly clear to everyone else

  5. #5
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    You mentioned MDF and ply in the same post, which set off my alarms. When I built a small bench, I was struggling with Ply for strength or MDF for smooth working surface, so laminated the two together for my bench. It works great... as a weather forecaster. The dissimilar materials expand at different rates, so sometimes my bench is convex and other times concave. Not a lot, but enough to bug me. The MDF has held up well enough that I would probably do MDF only in the future. If you don't have a vacuum bag to laminate the layers together, screw them together (lots of screws) from the bottom while the glue dries, then remove the screws. (Laminating is important... two layers of MDF is twice as strong as one, but one layer twice as thick (after lamination) is 8 times as strong, not just 2 times. (There is a third power in the formulas).

    CA glue has a funny property of no impulse strength. I know a fine woodworker who glues guides to his furniture for doing curved inlays, then removes them with a sharp tap from a metal hammer. The jar of the hammer-hit destroys the adhesive property of the CA glue, and the templates pop off without damaging the work piece. I bought some MinWax wood hardener to turn some punky wood, and it worked well. I have since done a lot more work with epoxy, so would probably go that route... if the holes needed it or started to fail.
    Charlie Plesums, Austin Texas
    (Retired early to become a custom furnituremaker)
    Lots of my free advice at www.solowoodworker.com

  6. #6
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    Thanks Charlie for the info, MDF alone it shall be, and the epoxy tip is in the safe . As to the weather forecasting, I have a knee that keeps me well informed .
    The perception of perfection is perfectly clear to everyone else

  7. #7
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    My workbench was made of two layers of MDF and it's strong. Two layers connected by glues and screws. I sealed it with poly. I kept pouring and painting till it didn't soak in anymore. Edged with oak. It takes a lot of activity. Ill have to try dog holes.
    Kevin

    In arte voluptas - in der Kunst liegt Vergnügen - in art lies enjoyment

  8. #8
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    I have some portable vise top tables that are made of 3/4 MDF. I have used them for years, and held various things. The plastic dogs they came with are mostly gone, but the holes are undeformed. My only issue with them has been that as I used them outside, they have occasionally been exposed to rain and I had to replace a top with pine last year as the MDF had swollen.
    Cheers,
    Roger


    The other member of Mensa, but not the NRA

    Everyone is a self-made person.

    "The thing about quotes on the internet is that you cannot confirm their veracity" -Abraham Lincoln

  9. #9
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    Thanks again guys...you should of seen my wifes face when I told her I ordered some dogs online
    The perception of perfection is perfectly clear to everyone else

  10. #10
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    Quote Originally Posted by Ken Cook View Post
    Thanks again guys...you should of seen my wifes face when I told her I ordered some dogs online
    Just tell her these don't need food or walks and won't bark or bite!
    A man is rich in proportion to the number of things he can afford to let alone. -Henry David Thoreau
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