Depron foam: The brand name of Depron in Germany is “Selitron/Selitac”. The foam is extremely lightweight, flexible and strong, and probably is the future of ultra lightweight RC model aircrafts.
Depron is a type of extruded polystyrene (XPS) closed-cell foam sheet material often used below parquet flooring to reduce step noises. It is available in two different colours (i.e. white and grey) and three different thicknesses (i.e. 2 mm, 3 mm and 6 mm). It has a density of weight comparable to that of balsa sheet.
When paints are used on white Depron foam, the applied colours come out nice and vibrant even without the foam being primed priory. However, please be certain that you are using only the water-based latex paints which are friendly to foam materials.
To assemble your model aircraft components made of Depron foam, you can use 5 min or 30 min epoxy, or any foam-safe glues such as the UHU por and odorless cyanoacrylate (CA) glues. Please be aware though "foam safe CA glues" tends to get brittle, and as a result the elasticity of foam material is reduced.
When use together with styrofoam-safe glue, Depron sheets could form a relatively strong bond with the glue due to the sheet’s high flexibility. Because of this good bond and high flexibility, the resulting model aircraft components made of Depron foam (e.g. fuselage sections) are relatively tough and virtually crash-proof.