help wanted for Embossed trim DIY

[lil lucifer]

I bought some material today (red vinyl) and gunna give the trim some pizazz. I have a few things I want to try but its my 1st go with these new ideas (embossed stuff into the trim) so it will be trial and error. I want to put some embossed shapes under the trim on panels within the door panels and glove box and consol lid etc.
Ive retrimed most of my cars in the past so i have an idea of what Im doing but only pretty basic stuff. No sewing just tucking, folding, glue and staples.
What Id like to know is What is the best material or substance to use for makeing and holding embossed shapes under upolstery vinyl? I was thinking hard foam like styrofoam but feel that would leave a rough finish. Maybe expanding foam once its set? Balsa wood? Wood? Fibre glass?
Ive been told that there is sponge foam that could do it but again I dont feel that would hold the shape for years to come as I defo want this to last a good 5 to 10 years. I want to have flames, skulls, stars for example so it would need to be strong enough to hold up the "licks" of the flames or points of stars but I want the material to be soft enough to work with. Should i forget vinyl and go for a cloth? If so what material?
Has anyone had any experience with doing this? Any general advice about upholstery is always appreciated as my knowledge is pretty basic.

[Fonzie]

Some guys on this forum emboss stuff into their headliners... They typically just use contact adhesive, and stick a layer of cardboard down in whatever shape they wish.

[hsvpunk]

a mate of mine used foam (im sure of it)
i will hunt the info now. and post it back up asap

[lil lucifer]

Some guys on this forum emboss stuff into their headliners... They typically just use contact adhesive, and stick a layer of cardboard down in whatever shape they wish.

Cheers dude, Do you know any of the profile names so I can pm them to ask what they did?

[lil lucifer]

a mate of mine used foam (im sure of it)
i will hunt the info now. and post it back up asap

Sweet! Cheers dude. Ill keep my eye out for ya post.

[butch123]

i am a motor trimmer by trade. just use some fexible cardboard, not the stuff with air pockets in it. make sure the contact adhesive is dry/tacky before you stick the vinyl on. then get something with a rounded blunt edge to define the edges of the cardboard. you can also use closed cell foam but i dont recommend it, the edges are more crisp by using cardboard.

[lil lucifer]

i am a motor trimmer by trade. just use some fexible cardboard, not the stuff with air pockets in it. make sure the contact adhesive is dry/tacky before you stick the vinyl on. then get something with a rounded blunt edge to define the edges of the cardboard. you can also use closed cell foam but i dont recommend it, the edges are more crisp by using cardboard.

Nice one. Cheers mate thats the juice Im after. Ive got a couple of tools used in making bow strings that will be great for the edge work.
So solid cardboard not corrigated. And I thought that the polystyrene stuff would be a bit rough edged.