Overriding form helpers

Hi there,
I’ve been trying to override the text_field helper with a version in my
application helper.
Whenever I try and call it from a partial I get the error:
“uninitialized constant InstanceTag”

I can override the text_field_tag no problem. But there’s lots of stuff
I don’t understand in text_field.
All I really want to do is set some common options for every text input
field on my site (class, size etc…)

is this possible?

thanks

dorian