I'm currently colouring my son's baby box (a gift box we receive from the government in Scotland which is made of cardboard and decorated with black and white pictures) using oil pastels and pencil. I'm hoping to use the box for keepsakes and give it to my son once he's old enough to not wreck it. However, now I'm going to have a box that is expected to be handled by a child that will be covered in oil pastel. So I need to find a fixative that will be resistant to frequent touch and also hopefully of low toxicity. I have done some research and it looks like lots of good spray fixatives can still leave surfaces sticky and smudgable, so I'm pretty sure I will need something that gets painted on, possibly a varnish? I have had a look at SpectraFix products as they are meant to be non-toxic and was about to go with their Natural Glass varnish before noticing it wasn't for oil pastels. Any fixative suggestions would be appreciated and tips on their application for someone who is a complete novice would be great. Thanks in advance
In all honesty, I wouldn't give this box to my child until they are at least a teenager. You can use the box for keepsakes in the meantime, but I wouldn't let my child have unsupervised acess to it.
Reason 1 is for safety considerations. Oil pastels have a soft consistency and are easy to smudge with your fingers. But even if there's a layer of sealant on top, it's still soft underneath which can cause any varnish to crack and flake off when being handled.
Maybe search the online shop of the manufacturer of the oil pastels you used for a special oil pastel fixative, or ask your local craft store for a suitable fixative. The advantage is that manufacturers produce their fixatives specifically to work best with their own brand of oil pastels. You can also use fixatives from a different manufacturer, but the results may vary. Just regular varnish won't stick to the oily surface. Be sure to follow the instructions of the fixative because applying too much melts the oil pastels.
Reason 2 is more sentimental. My mother also kept some objects from various times of my childhood and I always felt that there had to be a certain distance between the creation of the object and my appreciation of them. Maybe roughly double my age, meaning that I could appreciate a picture I drew at age 3 when I was 6 and I could appreciate my first writings I did at 6 when I was 12. Mostly because I forgot those objects in the meantime and could rediscover them, but also because it made me realize how much more advanced my drawing and writing skills had become since then.
The only fixative for oil based mediums is drying time, which can be months at the least. After the pigments are dry to the touch and do not smudge (test an small area not normally visible) you can preserve them with clear, oil based, varnish. The nice thing about this is that once they are dry and varnished they are fairly durable but it only works if the oils in the pigments are allowed to dry completely.