Custom ceiling moldings made of foam

[Sam_u_El]

Can't any of these staircase mouldings work as base material?

[link]

They don't quite have the dimensions we're looking for, even though it's the right type of moulding.

As it stands now, I'm going to experiment with pieces of foam plastic and MDF and make two test pieces to see if it's possible to get a decent finish. Otherwise, we'll order the mouldings from the planing mill.

I'll try to remember to come back and report the results once I've tested a bit.

 

[Fjojtmehmet]

They don't really have the dimensions we're looking for, even if it's the right type of trim.

As it stands now, I'll be experimenting with pieces of foam and MDF and make two test pieces to see if it's possible to get a decent finish. Otherwise, we'll order the trims from the planing mill.

I'll try to remember to come back with results once I've done some testing.

If you're working with MDF, you can achieve a perfect finish. I've made my own plinth trims for the entire house in MDF.
However, the joints have cracked on some due to the house moving, so I would advise against this.
A trim like you're showing could be made from a plank with a table saw without issues.
But if you need a lot of linear meters, I also recommend going to a planing mill.