Date: 201810
Local time of day: 0601-1200
Location: S50.Airport, WA
Flight conditions: VMC
Weather elements / visibility: Overcast Stratocumulus; 5
Light: Daylight
Aircraft: M-20 Series Undifferentiated or Other Model
Operator: Personal
Operating under: Part 91
Flight plan: IFR
Mission: Training
Flight phase: Initial Climb
Airspace: Class E S46
ATC / advisory: TRACON S46
Reporter organization: Personal
Reporter function: Single Pilot
Reporter qualification: Flight Crew Commercial; Flight Crew Instrument; Flight Crew Multiengine
Human factors: Confusion; Situational Awareness
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural FAR; Inflight Event / Encounter Weather / Turbulence
Result: Flight Crew Became Reoriented

Narrative: I was departing S50 (Auburn; WA) for IFR currency (practicing approaches in IMC). I filed a Round Robin IFR flight plan.Weather was MVFR at the airport at S50 due to Stratocumulus clouds; Vis > 6mi; Ceilings 1500-2000; tops reported at 3000-5000 ft. There is a valley; but terrain rises to the east.Once I was ready to depart (aircraft was in run-up) area; I was unable to get an IFR clearance on the ground using my VHF radio and had no cell phone present. (I had contacted SEA Departure on ground in the past.) I did reach SEA clearance delivery on the ground but they were too busy and provided me with alternate frequencies to SEA Departure; those did not work.I departed VFR; staying [in] the traffic pattern planning to contact Departure.Upon contact Departure was too busy with IFR traffic to give me my clearance; but said if I can maintain VFR heading south (getting to a different sector) I could contact them and get my clearance. Ceilings were level so I flew south at 1;100 ft MSL remaining east of the Class B Approach area for SEA. Once I was south enough I contacted Approach for my clearance; but they asked if I could provide my own separation up to 2;000 feet (sector MVA); which wasn't possible without breaking clearances.Ultimately; over Lake Tapps (VPLTP); I found an increase in ceiling (up to about 2;700-3;000 ft MSL) that allowed me to climb to MVA but; as I was climbing; I lost sight of my 'escape' route & airports and I realized that if conditions changed I might not be able to descend back down below the clouds safely. Reflecting; the decision to keep going (taking off into the pattern; traveling south; climbing into a 'hole') were all very risky. At the point that I was going to return to S50; I was considering declaring an emergency to get a clearance rather than trying to navigate back down below the clouds and to the airport.I should have dealt with the clearance on the ground not in the air. When talking to SEA Clearance; I should have been more direct to see if they could help get my clearance; and if not; then don't depart.Contributing factors:- Lack of planning for clearance (assuming VHF)- Forgetting Cell Phone- Mission mindset (departing expecting to get clearance)- Confusion with SEA Clearance (for connecting approach on ground vs. air)




Synopsis: Mooney pilot reported becoming disoriented and entering IMC conditions while trying to get IFR clearance.