STEP 1: Paint the entire outside of your bangle using black acrylic paint.
STEP 2: Paint the entire inside using silver gilding.
STEP 3: Paint horizontal stripes around the bracelet using silver gilding.
The way I did this and tried to make it look even was to make the stripes the width of my brush. I painted one stripe to start, then painted another directly across from it on the opposite side of the bangle. Then, I painted a stripe in between those two, and one directly across from it. I repeated that until I had 8 stripes that were pretty evenly spaced.