How to build a solar flare model?

In my past years at Duke we built many scale models like this. What you described is an unconventional way but nonetheless feasible. We used much more advanced technology; obviously unattainable to a school boy with a math project. Your best bet is to dip the Solar model in kerosene, first allowing better tint of actual sun spots. This will also decrease the size of the flame, making it far more safe.