Pull coating off foam or not

[91rioja]

As I was tearing out my old layout, I noticed that everything came off of my blue extruded foam rather easily. I was using white latex caulk to put the roadbed on the foam, and the clear latex to place the track to the roadbed (that would NOT come off without a fight). My foam has about a 1 mil clear coating on it. So, I'm wondering if that coating should come off or not before putting any latex caulk down.

Has anyone had experience with this?

 

[yellowlynn]

Yes, I found out about it by accident a few years back. I painted a base coat and then started doing a bit of plaster. I lucked out in that I hadn't done much. It was close to the edge and the plaster had set enough, that when I wanted to change it, that film pulled up. I thought it real strange that paint and all wanted to come up. Aha! That is when I found out. It is kind of hard to get started pulling it off, but once started it comes pretty good. Sometimes I had to scrape and dig to get started, but I wasn't about to put hours and hours of work in and then have that film loosen up.

Lynn

 

[JDC916]

So are you saying it's best to remove that coating before getting started or leave it ?
I just finished my bench and was going to get the foam board tomorrow.

 

[yellowlynn]

I definitely remove that film before I ever start. The only way I would leave it on would be if I possibly intended to remove everything later. I've never seen a time for that.
The blue foam I got had that film on both sides, and as soon as I was ready to use a sheet I made sure I stripped both sides.

Lynn

 

[bigsteel]

the film on both sides is a vapor barrier to protect the house against condensation in the walls.i usually get foam without since it says nothing about "vapor protection" and such.i use pink extruded foam which doesn't have a vapor barrier and after using blue once,ill never use it again unless its free.hope this explains it--josh

 

[MasonJar]

I understand that some foam is actually permiable, hence the need for a vapour barrier. Either that or it has something to do with the manufacturing process. In either case, I would remove it before adding anything to the layout. If you put a layer of latex paint on, the foam will be sealed regardless, and your scenicking materials will stick much better...

Andrew

 

[91rioja]

Thanks guys.

I pulled up my layout yesterday; I will have to say that the nice thing about leaving the film on was that everything came off of the foam without any problems. I will be able to re-use it for my new layout.

So, plastic off it is.