Foamcore for the coffins themselves, definitely. As for the support, wood is definitely a good choice if you can find a type light enough. To get the angles you want, perhaps try PVC connectors?
DeviantART // Tumblr // Facebook // Instagram
- Pearl (Steven Universe): 34% (Sewing) Winter/Spring 2016
- Labelle (Animal Crossing New Leaf): 96% (Final Details) Katsucon 2016
- Pyrrha Nikos (RWBY): 56% (Weapon Work) Katsucon 2016
- Pyrrha Nikos Weapons (RWBY): 50% (Carving Sword) Katsucon 2015