60D using onboard flash to trigger a 430EX II. Can you avoid the on camera flash?

Hi, As explained above, the output of the built-in pop-up is essential both for ETTL proper exposure, if exposing with that unit contributing to the captured image, & for controlling a Canon Wireless Light/IR type network.

If you want the pop-up to contribute to the exposure and you want ETTL to control its contribution, then its 'Pre-flash' must be unimpeded.

Conversely, if it (the pop-up) is correctly set not to contribute to the captured image and beyond that, you wish to totally avoid in-sync 'trigger-flash' too, but, you still wish it to control a Canon Wireless IR/Light type network, then an IR-pass filter is by far the best choice. Nikon's SG-3IR - suitably modified - is a great solution. Cheers, Donald

PS. When you say " .. overexposes my pictures when taken indoors in the daytime or in a brightly lit area .. " bear in mind that using flash, the pop-up in this case, always limits the cam back down to the max sync speed. So it is likely that it is the ambient light component that is over-exposing those images, rather that the pop-up's contribution.