My sons have collected too many crayons, and as connoisseurs of fine crayons, they only like to use their Crayola. As I was purging their old crummy crayons I thought this might be a fun way to reuse them.

It is best to approach this project as an experiment with your kids, as there are lots of factors that can affect the end results - and therefore lots of great questions to explore.

This project does require a heat source to melt the crayons. Use your best judgement as to whether this craft is appropriate to do with your kids. The heat gun is hot and the crayons are hot when they are melted.

Supplies

Wood (about 4" x 16" x .75") (10.15cm x 40.65cm x 1.95cm)
Old Crayons
Heat Gun
a hair dryer also work well
CNC
or a handheld router, scroll saw, jig saw or coping saw

Step 1: Carve Out the Names

There are several different ways to carve out the names. The recess has to accommodate the pieces of crayon which are .3 inches (1 cm) in diameter. So your depth needs to be .25" - .3", and the letters have to be at least .3 inches wide at any point.

I font I used is Anton, with the letter 3 inches (7.62cm) tall.

CNC

I used a CNC machine to carve the names out of 3/4" poplar. I carved at a depth of .3 inches. If the letters are too shallow the crayons will over flow, or bleed into the wood grain as they melt. Solid wood was best, or high quality plywood. With cheap plywood there are voids in some of the the inner veneers that can cause detail of your letters to chip out.

Scroll Saw / Coping Saw / Jig Saw

The same effect can be accomplished without a CNC machine. Instead, start with two pieces of wood that are each .25 inches (.64 cm) thick. Sketch out the name, or print out the letters to create a template on one of the pieces of wood. Cut the inside of the letters away. Glue the remaining 'outside' of the letters to the other piece of wood.

Hand Held Router

If you have a palm router or trim router your could also route out the letters by hand.

Step 2: The Crayons

Peel the crayons. The worst part of the project by far!

Chop the crayons into smaller pieces (.25" to .75"). The more uniform the pieces, the more consistently they will melt.

Have your kids fill up their letters with pieces of crayons.

Once the crayons have been arranged, it is time to melt them. Depending on the age of your kids, you can do this while they watch, or they can handle the heat gun with your supervision. With the heat gun on its lowest setting slowly heat the crayons up. Try and heat all the crayons up uniformly.

I did this in my kitchen under the range hood. You could also do this outside.

If you over heat the crayons they will smoke, and can even catch fire. Do this step slowly, and at the lowest temperature possible

Best Results

I also did a sample in our toaster oven at a low temperature. it worked, but the crayons did not melt as uniformly.

Some types/brands of crayons melt at different temperatures than others. Because we used all sorts of different crayons, I had lumps of some crayons that did not fully melt. This is also why the toaster oven did not work as well. For better results you can use only one type of crayon. It also helps to cut the pieces into uniform sizes.

As the crayons cooled, some of them cracked. I think this is because they got too hot, and cooled to fast. This might be resolved by bringing them up to temperature slower. I also tented with aluminum foil to try and slow down the cooling - I'm not sure if this helped.