So a little while ago when deciding that I wanting to make a blackboard for my kitchen, I came across the idea to put one into an old picture frame. I just began with a small frame to test it out and was very pleased with the end result. Here's what you do..
Have a good rummage around your second hand/ thrift stores for some cheap old paintings with great frames you like. I found this lovely English countryside picture for $1.
Then you will need a pot of blackboard paint (you should be able to get this from most hardware stores), a paint brush, some tape (to tape off the edges), and if your paint is enamel based then you will also need some turps to clean your brush with afterwards.
I use Taubmans Blackboard Interior Chalk Board Finish.
On the paint pot it does advice you to do an under coat of white paint first so that you get a good surface. In my usual impatient ways I didn't bother and it turned out fine. It suppose it really all comes down to what kind of material you are painting onto. So the next step is to carefully tape around the inside edges of you frame because you don't want to get paint on that. Paint the first coat (this is rather exciting!).
Wait for the first coat to be completely dry (this takes a looong time), and then apply a second coat.
Again leave it over night to dry. In the morning you can peal the tape off from around the edges and then it's time to have some fun! Take a piece of chalk and colour in the whole blackboard (I'm not sure why this is necessary but that is what the paint pot says to do). Then wipe it off again and TA DA your blackboard is complete and ready to be used.
Making your own blackboard is so simple and so much fun! If you have children it is definitely a fun rainy day activity you could do with them too.