I've got a Medium-density fibreboard (MDF) sink cabinet that is at least 30, if not 50 years old. The bottom has gotten wet a few hundred times from a shower that was near it, and it is flaking apart at the bottom where it meets the linoleum. It's also right by the laundry shoot, so it gets rubbed on a lot. I'd like to patch it with something water resistant, then paint and sand the whole cabinet smooth.

What should I use for patching it? Is there something more water resistant than wood putty? It should be fine if a soaking wet towel gets thrown next to it and sits for 3-4 hours a dozen times. I will yell at the kids, but I'm sure it's going to happen.

NOTE: I will probably sand off most if not all of the paint, so a thin coat of whatever on the paint or the MDF should be fine.

  • 3
    Probably only 30 since MDF didn't come into widespread usage until the 1980s.
    – bib
    Commented Feb 5, 2013 at 22:52
  • MDF is the paper woven board right? Is there a different type of material that is flaky?
    – RLZaleski
    Commented Feb 6, 2013 at 0:49
  • 3
    Fibreboard is a low density composite that has a woven quality. Wood chips in a flaky random pattern is often called particleboard. MDF is a fairly dense smooth cocoa brown board with no significant texture or color variations.
    – bib
    Commented Feb 6, 2013 at 1:11

1 Answer 1


You probably want an epoxy based filler such as Bondo. A variety of manufacturers have a version of this.

These products are a little more complicated to use than traditional wood fillers, but they are pretty impervious to moisture once they harden. You need to mix small batches that can be used in a few minutes. Nitrile/latex gloves are a must.

Once done, better than wood or MDF for durablility.

  • +vote for Bondo. Bondo is great for repairs in this type of situation or outdoor trim. It can be a little difficult to use and shape/sand, but once you get the hang of it, it is a great water resistant filler. Commented Feb 6, 2013 at 11:07

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