Mold Super-Quick Edge Guards for Sharp Tools

Woodworkers need to keep their tools sharp, and if you aren’t careful, it’s easy to chip them or cut yourself badly on a properly sharpened tool.

Edge guards are a great Maker project, but they can be difficult to construct with a snug enough fit on the tools. Many people have used plasti-dip for this purpose, but plasti-dip tends to be very unfriendly to work with, and can result in a fairly loose fit. Enter low-temperature thermoplastic.


This stuff goes by a few different brand names: ShapeLock, InstaMorph, Fantastic Plastic, and Plasty Craft, to name a few. It comes as a bag of little plastic beads, which you can melt in hot water and form into anything you want. It’s a good choice for this project because it sets up to a very stiff guard, but one which takes on the exact shape of the blade to ensure a tight fit.

Recently, Todd Treece posted a how-to article over on the Adafruit Learning system walking you through the steps to create your own edge guards. The process is pretty straightforward, actually:

  • you simply heat up a load of thermoplastic,
  • form it into a rectangle about twice as wide and long as you’d like the guard to be, and
  • fold it once over the blade lengthwise before folding the resulting shape into thirds around the tool.
  • Once the thermoplastic has partially hardened, the guard can be removed from the blade and trimmed to the appropriate length.
  • After that, allow the guard to cool and dry completely.

That’s it!


And the best part is, the plastic is reusable: if you mess up you can just start over, and trimmed plastic can be re-melted and used for another project. Don’t forget to coat your tools in jojoba or mineral oil before placing them in the guard to prevent rust, and happy woodworking!


Tony is a web developer from Springfield, MO who enjoys 3D printing, electronics, programming, and anything outdoors. He is currently a developer for Adafruit Industries.

View more articles by Tony Sherwood