Touch Sensitive Lamp

Dear all,
I'm Matteo and I've developped and mouted a simple lamp with the touch control and light dimmer.
I've used to test the lamp a small piece of aluminium and everithing works fine. But at the end I want to use the lamp frame that is done with metal (iron) (it is a big metal plate 1,37 m height) with inside a wood part .In this case arduino return as is always in touch. Which is the problem in your opinions metal part too big, the wood, the metal was painted? Actually there is a 100KOhm resistor, make sense to try different values?

Best regards and thanks for yours helps
Ueo

Please do not hijack. Thread split.

For a capacitive touch sensor, have a small sensitive area in the frame, isolated from the rest of the frame. Connect the frame to GND and the sensor to the I/O pins, as indicated in a touch sensor tutorial.