I built a case for my Mandolin - finally! I used an easy -ish method - foam and covering - in this case - polyester dress lining fabric + diluted wood glue .... Of course to make areally strong case - you could use other materials - like plywood - etc. This was just me having a go at a qick and easy-ish technique - and it orked! If you try this yourself - please leave plenty of time for all glues and paints to fully dry - otherwise they could adversely affect your mandolin!
Feel free to check out my other vids on this subject;
Build a custom case for - anything - (easy-ish)!
https://youtu.be/cKDHSXmh5xs
Foam covering - strength testing....
https://youtu.be/9d25EYnPo3c