Firstly I cant take credit for the idea, my son saw this on Blue Peter (kids TV show in the UK) and I thought it was great activity to do over the school holidays.
Its nice and easy to do and he had great fun doing it, its also a great way to use up all those old wax crayons that end up at the bottom of their colouring box.
Step 1: Materials
Ok so the things you need are:
A canvas or board to mount the crayons on to
Newspaper or scrap paper to protect you work surface.
The first thing to do is apply a generous amount of the PVA glue along what will be the top of your picture and then start sticking the crayons along the top edge.
They can be stuck on however you like but I would advise grouping colours together to create something like a rainbow effect. If you mix colours up too much they will run in to each other in the next step and make a bit of a brown mess.
You will need to leave the PVA to dry now, for us this took about an hour or two.
Ok so now the fun part, applying some heat.
Care should be taken at this stage, hairdryers can get hot and so can the wax once melted.
My son is 7 so I was happy for him to use the hairdryer himself with my supervision and a little assistance. You will need to decide if you take over here or not.
Make sure you have something on you work surface to catch the dripping wax, you then want to prop your canvas up against something (again protect with some scrap paper as the tops of the crayons will also melt).
Apply the heat from the hairdryer directly to the crayons, I would recommend having it on the slowest hot setting you have, if you have too much air blowing out the wax tends to go a bit crazy and blows all over the place.
Try and apply the heat evenly across all crayons, I did find some melted quicker than others so we had to pick and choose areas to concentrate on. Let the wax run down the canvas, you can use the hairdryer to direct the flow of wax a little if you want/need.
We had a build up of wax at the bottom of the canvas so to finish it up I took over and held the canvas up and applied heat further down and allowed it to all drip off. Its up to you if you want to do this or not, I also used a Stanley knife blade to trim off the drips hanging from the canvas as my son insisted he didn't want them there. They can be left however and may look cool.
Leave to cool down for a few minutes and there you have it :) Have fun!