Crochet a chain of the length you need for using thick wire (0.5 mm) and hook 1.5 mm. To get even round loops, stick your hook into each already crocheted loop so that the loop takes a round shape of shaft.
The total number of loops (together with the connecting loop) should be divided by 3, I got 75 loops for a length of 20 cm.
Connect ends of crocheted chain to get circular shape.
Crochet a hemisphere using thin wire (0.1 mm) and hook 1.1 mm, work in rounds, do not turn, use a stitch marker for the first stitch of each round (or mark using a piece of thread), after each crocheted round, pick out the loops using the needle.
1st RND: 6 sc into magic ring.
2nd RND: inc in every loop. (In total you will get 12 stitches in this round)