Terminology: Some places use the term "wood filler" to include all fillers. SF Gate makes a distinction between filer (indoor) and putty (outdoor). However, Minwax WoodPutty is interior only.

Wood filler differs from wood putty in that the filler usually consists of sawdust or wood fibers suspended in a binder, while putty is usually a plastic such as epoxy, fiberglass or polyurethane. Moreover, unlike filler, putty doesn't harden. Wood filler isn't weatherproof and won't last outdoors. Epoxy - Better for large areas. Wood Putty Vs. Wood Filler | SF Gate

Best Wood Filler in March 2018 - Wood Filler Reviews:
3M Bondo Home Solutions Wood Filler Epoxy - Best Exterior
Elmer's E887 Stainable Wood Filler, 3.25-Ounce - Wood Fill - Amazon.com

Test Results

  • MH Ready Patch - oil based but cleans up with water.
    oor Ready Patch. The patch showed significantly more deterioration this year. The gaps at the perimeter are growing quickly and showing signs of lifting out of the wood, while the center of the patch continues to sink lower.
  • Minwax Wood Filler - At year two, there is still very little wear on this product. It does show more perimeter cracks this year, adding up to about 40%. It has also developed a very slight crack about a third of the way into the filler.
  • Minwax High-Performance Wood Filler
    This patch really accelerated its rate of decay. Perimeter cracking is now at approximately 85% and it has begun to develop two cracks within the body of the patch that are larger than any of the other products.
  • KirkWood Epoxy filler - Best - There has been very little change in the KwikWood this year and the first year. The perimeter cracking has expanded a bit more to approximately 80% of the patch, but it remains very slight hairline cracks.
  • The gaps at the perimeter are growing quickly and showing signs of lifting out of the wood, while the center of the patch continues to sink lower.
  • Durham’s Water Putty - powder
  • DAP Painter’s Putty - oil based
Links:
The Wood Filler & Epoxy Test (Year 2) | The Craftsman Blog
The 7 Best Products to Patch Wood | TheCraftsmanBlog
Caulk page.
How to Repair a Deck With Wood Filler | Home Guides | SF Gate

last updated 22 Mar 2018