Priming before final assembly (NOT a primer question!)

I know this is a silly question, but I'd rather sound like a fool than be one. Can I prime completed sections anytime I want, or do I have to wait for the DAR inspection of the completed plane before priming/painting the exterior? I tried an Internet search but couldn't find a clear answer.

(Did find some surprisingly useful information from the FAA about painting aircraft here: https://www.faa.gov/regulations_pol...raft/amt_airframe_handbook/media/ama_Ch08.pdf )

I have the vert. stab. and rudder hanging from the rafters. I had the thought that it might be fun to prime them one of these weekends when I have nothing else to work on, but every photo I've seen of someone smiling with their final certificate was in front of an unpainted plane. I had a disturbing thought of the DAR telling me to reschedule my inspection once I've stripped off all the primer.

Syrus

Syrus, I can't answer authoritatively, but I can contribute two data points. I know of two local builders who had planes signed off that weren't bare metal. One built a Rocket that was primed when I saw it well before the inspection, and an RV-12 builder who painted his plane in sections as he finished them, also before the final inspection.

There should not be an issue with priming the outside unless the coat is so heavy that it covers rivet heads, etc. The only caution I would add is that if you plan on having a professional painter do the final coats, that person may end up removing your primer to make sure it is consistent with their paint and techniques.

We don't care if the aircraft is unpainted, primered, or painted. Your choice.

Just be sured that your weight & balance is done with the same configuration as presented.

Keep in mind that priming but not painting the exterior is almost a total waste of time and materials.
Most if not all primers nowadays require them to be top coated with paint within a maximum time window (sometimes as little as 24 hrs) to get proper solvent induced cross linking for good adhesion.

If you prime and then paint much later, you will have to sand the entire surface to get the paint to bond to the primer. Even then I don't think the cross link bond is as good as if you top coat within the recommended time window.

If you really want to prime, you should top coat with paint also.

eewwww.....Thanks Ken. That's no bueno.

I'm starting to see why people build more than one plane. I'm going to know everything I need to know about building a plane...about the time I'm done building a plane.