Part of Lesson Plan: Cool Cutting Boards

Activity Overview / Details

I have two bar clamps on the workbench along with a bottle of yellow resin polyvinyl glue such as Tiebond II (weather proof), and several strips of varying wood species roughly 3/4 thick, 18 inches long in a variety of widths from 1/8 to 3 inches.   I also set aside some longer and very thin (1/16 or less in thickness) strips for lamination into a curve.  

(Teacher Note: My wider wood strips are mostly made of hard maple.  This wood makes a superior cutting surface and is a closed grain wood.  My thiner strip tend to be walnut, jatoba,cherry, ash, and other darker woods. I use as much as I can from the scrap bin.  For my 7th grade classes I pre-cut all of the strip for the class.  You may wish to demonstrate how to cut all the pieces if your students will be cutting the strips for their boards).

Draw a gentle "S" curve in one of the strips and take the class to the band saw (see band saw safety on this web site for more information about the band saw).  Demonstrate cutting the curve on the band saw and return to the glue up bench.  Demonstrate how very thin strips can be placed and bent into the curve to make a very interesting detail in your board.  If the curve is too tight or the strips are a bit too thick you may need to soak the strips in warm water for an hour or so to make them playable enough to bend without braking in the curve. 

Show the glue and ask the students if they think that gluing wood forms a physical or chemical bond.  Discuss the fact that yellow resin polyvinyl glues are specially designed to form a chemical bond only with wood.  (Technically, this glue is a group of organic chemical compounds in which the carbon atoms are linked in open chains).

To make a good edge joint you will need straight, square, clean edges.  You can not have rough edges or edges with dried glue on them as these will form poorly constructed joints like the ones in the broken boards.  A rough edge will not provide enough surface area contact creating gaps and dried glue will not allow a chemical bond with the wood. Good joints provide for a seamless look. (You will not have a problem with the slightly rough cut of the band saw).  

Show the class how to arrange the strips by mixing the wood species as desired. There is plenty of opportunity here for students to individualize their boards.  Each one will look different than the other.  

Demonstrate how to dry clamp the strips together by alternating three bar clamps, two under and out toward the ends of the board and save one for the middle to be placed on top. The top clamp helps counter act the bowing up of the middle of the lamination by the other two clamps.  Also emphasize that dry clamping is a good way to find any problems that may appear in your boards such as gaps in the edge joints BEFORE your start gluing. 

Demonstrate how to apply a thin layer of glue to all mating surfaces. Students typically use too much or too little glue so take time to describe and emphasize that the entire surface of the edge must be covered with a thin layer and that clamping will NOT spread the glue for them.  They must spread the glue (I use my finger). I often demonstrate this fact by running a bead of glue on one board and clamping them then unclamping them and showing the students all the places on the edge that did NOT receive glue.

Tell the students what the working time of the glue you are using is.  "Working time" is the amount of time you have before the glue starts to set and this will vary depending on the type of glue.  Check to see what your glue's working time is.  You don't want students to go looking for clamps and more wood strip once they have started gluing.  Make sure they know this.   Students should have everything they need at the bench BEFORE they start gluing.  You also don't want students starting their glue ups just before the bell rings so make sure they have the time to start their glue ups.

Have students help you finish gluing up the strips and putting them into the bar clamps.  Demonstrate how the strips on one end of your board should be mostly even and how the board should be made as flat to the bar clamps as possible.  Glue can make the wood strips slide around.  Holding them down as you apply pressure to the outside clamps will help keep them in place.  You may need to apply a bit of pressure and tap the strips down with a mallet as you increases clamp pressure to keep the strips in place.  Place the middle bar clamp on top and tighten.  Check to see if the board is flat to the bar clamps by sighting the boards along the bottom clamps.

Show students where to store the glue ups and tell them that the glue will need to cure for a full 24 hours. 

Check for learning and allow for questions.

Day TWO

Take a previously glued board and demonstrate scraping the dried glue with a glue scraper.

Demonstrate the proceed for face planing on the surface planer or wide belt sander.  Remember we want as thick a board as possible.  Cutting boards are more valuable the thicker they are. 

Check for learning and allow for questions.

Have students start cutting and gluing their boards.

Day THREE

Demonstrate drilling a hole in the cutting board.  Take a previously planed board and show the class how to drill a hole using a 1, 1/2 inch foster bit in a drill press. Have a discussion about "chip out" and make sure to use a scrap wood back up board to prevent chip out. ( see drill press safety on this web site for more information about the drill press).   The hole must be far enough away from the end and edge of the board to keep the surrounding material from breaking over time and though use.  Have the students measure to 1, 3/4  from the edges in one corner of the board to mark the center of the hole.  This will leave one inch of material around the hole.

Demonstrate how to use the router table with a 1/4 or 3/8 inch round over bit in a the router.  Round all edges including the hole.  You may need to closely supervise the routing of the hole as this is a tricky cut and may require moving the guard to a higher position. 

Demonstrate how to finish sand with an orbital sander.  Last, apply mineral oil with a rag for a nice finish.

Check for learning and allow for questions.

Students continue work on their boards.

Day FOUR

Students continue work and finish boards.