Is it true that an experimental aircraft can not be instrument certified
by
the FAA?

If it is there are a lot of them out there flying IFR illegally.
(unless I'm missing something in your phrasing)

My question is about the aircraft not the ability to fly it in IFR
conditions.
I recently showed my instructor an ad for a Glasair and he remarked that
you could never get it IFR certified with the FAA.
That didn't make much sense to me, but then again I am the student and he
is the instructor.
The way I figure it, if it is IFR equipped then why couldn't it be IFR
certified?

David