Isolate a capacitive touch switch

I am running the Trinket MO with CircuitPython with the example capacitive touch code and it works great with the wire on a breadboard.
I soldered the wire to a small piece of copper and it works great.
When I mounted in a project with a touch of silicone....the switch was erratic.
What is a good way to isloate this switch when everything has capacitance?
Thank you