Hi.
I made a flight-case for an Epi LTD Explorer, and also a pictorial about the project.
Making a custom case for Epi LTD Explorer
All traditional flight-cases are heavy and this puppy ain't an exeption.
A vacu-formed plastic case would be the lightest option (perfectly DIYable), but nothing protects an instrument quite as well for the weight (and price) as a 7mm plywood flightcase.
IIRC there was a thread in the luthiers corner for a plywood cutout case as well. I believe mine is the lighter one of those two

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Regards
Sam
Regards
Sam