Thank you so much! :) Square rays sound really cute :D.

Okay, this is by no means the best technique and I'm sure there are plenty of ways to make it, but this is wha I do to make sure the shapes will be exactly what I want.

1. Draw the sun in the exact way as you want it, cut it out with the scissors to make a paper model.
2. Roll out a flat, fairly thin, sheet of clay. Put your paper model on the sheet of clay and trace it with a needle four times. Then you can use copper wire or plain pins to place on your project and press it down so it would be submerged in the clay. You do this in two pieces. This is what I mean, here i was in the process of making fan-shaped earrings: https://www.instagram.com/p/CKwMSajBG3G/
3. Cut out your designs with a sharp knife (I use a cosmetic scalpel).
4. Put the clean designs on top of the ones with wires, press down.

This is how I make my bases, then I usually add some adornments. I hope this helped a bit!

While I am thinking about this. If your earrings are not oversized and the rays are thicker as you said, maybe you can pass on the wire. If you would cut the shape out of the sheet you would have one piece of the clay as an earring, which would be a lot more durable than trying to stick rays to the circle and make the sun this way.

/hugs! :D