KING AIR FLIGHT CREW ENTERS IMC ON DEPARTURE WITHOUT AN IFR CLEARANCE.

Narrative

I WAS THE PLT IN TRAINING UNDER THE DIRECTION OF THE PIC/TRAINING CAPT FLYING BEECHCRAFT KING AIR DEPARTING ON A PART 91 LEG. THE WX CONDITIONS AT THE TIME WERE RPTED TO BE 6000 FT BROKEN AND 10 MI VISIBILITY. PRIOR TO TAKING THE RWY; I COULD CLEARLY SEE STARS IN THE SKY OVERHEAD WITH NO CLOUD COVER. UPON CLBOUT WBOUND; I LEVELED THE ACFT AT 8500 FT IN VFR CONDITIONS. THE PIC/TRAINING CAPT TOLD ME TO CLB HIGHER AND UPON COMPLYING WITH HIS INSTRUCTIONS; WE ENCOUNTERED CLOUDS AT APPROX 9500 FT. I INFORMED THE PIC/TRAINING CAPT THAT I WANTED TO RETURN TO VMC AT 8500 FT. HE INSTEAD ORDERED ME TO CLB THROUGH THE CLOUDS TO GET ON TOP. THE FLT CONDITIONS WERE IMC THROUGH APPROX 13500 FT WHEN WE BROKE OUT INTO VFR CONDITIONS. DURING THE CLB THROUGH IMC; THE PIC/TRAINING CAPT ATTEMPTED TO OBTAIN OUR FLT IFR CLRNC FROM CTR BUT ONLY AFTER IT WAS APPARENT AT APPROX 12000 FT WE WERE NOT GOING TO BREAK OUT OF THE IMC. WE DID RECEIVE OUR FLT'S IFR CLRNC FROM CTR AFTER SEVERAL RADIO CALLS. THERE WERE NO OTHER ACFT OBSERVED BY US OR HEARD FROM IN THE AREA W OF US AT THE TIME OF THIS INCIDENT. LESSONS LEARNED: 1) FOR SAFETY OF FLT; WHEN IN DOUBT ABOUT THE FLT/WX CONDITIONS ALONG THE RTE OF FLT; OBTAIN AN IFR CLRNC PRIOR TO FLT. 2) WHEN INADVERTENTLY ENTERING IMC WITHOUT A CLRNC; RETURN TO VMC AS SOON AS IT IS SAFELY PRACTICABLE AND REMAIN SO UNLESS SAFETY DICTATES OTHERWISE AND/OR UNTIL AN IFR CLRNC IS RECEIVED.