Is it possible to plaster on this material, check the picture

[fender stratocaster]

Now I am going to plaster a surface outside and you should have dead material behind. Everyone says different things about whether it works or doesn't work on styrofoam, outdoor gypsum, plywood, etc.
This has been on our house for 40 years. I should be able to screw this onto the wall and plaster against it, the surface is about 50 by 200 cm

 

[fender stratocaster]

 

[SBH]

can apply plaster to everything. with varying results. image not visible