I’ve tested various ways to inconspicuously embed a post in a baked polymer clay hoop earrings without using glue or resin. The best way I’ve found is to I drill a fairly large hole in the end of the baked hoop earring about 1/8″ – 3/16″ deep, insert a piece of wire with a little hook bent on the end, and then fill the hole with a paste made of clay and liquid clay. The hook is necessary to prevent the wire from pulling out after it’s baked.
If the hole is too small, the post will exert pressure on the clay and the clay could crack while baking, so be sure the hole is large enough that you don’t have to force the wire into it. You can use super glue to hold it temporarily before you fill it with polymer, but it’s usually not necessary. After filling with a paste of clay and smoothing the surface so it blends in, adjust the wire so it’s perfectly aligned with the earring. Prop up the wire with pieces of card stock so it doesn’t sag while baking.
Pre-made posts with heads on the end may be too short, so I use a piece of 21 gauge sterling wire, cut it to the proper length after baking and then sand the end so it’s round and smooth.