I finished the frame up for my first section of my layout. 1x4 frame work with 1/2 plywood gussets for squaring it up. In the past I have always used plywood as the tabletop. This time I want to go with the pink foamboard. How does one go about attaching the foam to the frame? Glue? Caulk? Screws? A combo of these? I am thinking about going with 2" or would a double layer of 1" be easier to work with when creating landforms?
Robert H. Shilling II
The most common fastener is latex caulk or something similar. Many of us use Liquid Nails for Projects. This is applied from a large tube with a caulking gun. The same stuff can be used to attach roadbed to the foam, and track to the roadbed.
It takes an iron man to play with a toy iron horse.
I commend you for wanting to use foam instead of plywood.
How to attach? Forget screws. They'll tear up the foam unless you use those huge plastic washers that hold foam panels in place for building insulation. Glue and caulk will work well if you have enough contact area. The caulk might be easier since it sets up quicker.
You don't mention how big your framework is and if you have intermediate stringers in the framework. Does the foam sit on top of the framework or nestle inside it? If it sets down inside the frame, you may not need any adhesive at all.
2" or 1"? Often comes down to what's available and what the cost difference is. 2" is going to be more ridgid. Carving into 2" to any depth may take more effort. You can also laminate 2 pieces of 1" to get the 2" thickness. It won't be as strong as full 2", but it will be close. You may also consider using 1" foam as an underlying base and laminating more 1" foam only in areas where you want the increased height. Use a very thin layer of adhesive caulk between laminations.
Hope this helps.
Darrell, quiet...for now
This section of the frame work is 16" x 6'-7". It is the first of the sections that will go around our spare room (which is only 6'-8" X 13'). There will be one more section that is roughly 3' x 4' and the rest will be 12" x whatever length needed to fill in between sections and a removeable "bridge" near the doorway. I have to compromise on this space since it is also the missus sewing room.
The foam will set right on top of the framework and I have stringers every foot. I think I will go with 2" as it will allow me to do most of what I have in mind right now. I can build up from it and cut down into it.
I glued my 2" foam to my 1x4 framing with PL300 Foam Adhesive. It says to apply adhesive and then pull apart to vent. I tried doing this and there was no way the foam was coming off again to vent LOL.
I think latex caulk would also do the trick and it would allow you to salvage the foam if you ever wanted to use the foam again. I am very happy with my decision to go with 2" foam on 1x4s.
Brent
"All of the world's problems are the result of the difference between how we think and how the world works."
I have used both PL300 and liquid nails for projects and feel that the PL300 is far superior. It is much tackier and seems to have a better wet hold That said you still need to apply some pressure to keep the foam pressed tight on the frame. And it can take a long time for it to completely harden. I would give it 2 or 3 days if you are glueing to your frame. If you glue foam to foam with PL300, I'd give it close to a week to completely harden.