Homasote vs Plywood.

[dcarrell8]

Thoughts on using homasote over plywood for large flat areas of your layout vs plywood alone. 

The area will be a small town with half a dozen rail serviced vendors.  The area will essentially be 2'x 8' with non right of way areas cut away from the plywood for varying depth of the scene.  Just not sure if I should use homasote as well as the plywood.

Thanks for your input
~Dennis

[C855B]

Why isn't pink foam somewhere in your thinking?

I'm not a fan of Homasote. That's old-school, reinforced by ancient HOers clinging mightily to the how-to books of the '60s and '70s. Back then, when it seemed like I was the only one interested in maintaining the club layouts I belonged to, I found it to attract dust and dirt, and be its own source of dust. Tearing down those layouts was a double-dose of how messy Homasote could be, especially if it got wet at some point in its life. Yeah, it held spikes nicely, but we don't use spikes or nails with N scale track any more. Besides, try finding Homasote at any of the big chains like Home Depot or Lowes, it's been long out of favor with construction professionals.

Consider 1/2" pink foam topper, or 2" pink foam without the plywood.

[MVW]

Yep, homasote is definitely old school, and in this case that's not a compliment.

One caveat with the 2" pink foam: The stuff I usually see at my local "big box" stores tends to have unwanted dips and valleys, apparently as a result of being strapped to a pallet during transit. Unless I need the relief, I usually go with 1", which seems to survive transit with fewer deformations.

Jim

[dcarrell8]

Without a doubt though you do suggest a plywood base correct? 

Thanks for the input!  I have both, I guess it's time to try the pink stuff....  What should I use to adhere it to the plywood, track and roadbed.  I presume white glue is not an option.  I've used Gorilla glue for foam on land forms and I honestly hate the stuff, but It does cut with a hot knife.

~Dennis

[TLOC]

I used liquid nails for foam from HD. No problems with it coming up in 5 years now.

Tom

[Steveruger45]

I use the blue foam from "Lowes" and stick it down with liquid nails projects, after peeling off the thin clear plastic sheet coating it . I think the Blue and the Pink foam is pretty much the same other than the color.
Anyone know different?

[C855B]

... Anyone know different?

Yes. Pink (Owens-Corning) is stronger than blue (Dow). Important if you are relying on the foam by itself for the benchtop and not as a layer over plywood. In comparison testing of 1/2" and 3/4" XPS (extruded polystyrene) foams, blue sagged sooner under less weight than pink. The film on blue is for vapor barrier and IIRC might only be on the 1/2" material. The film does add to strength, but I peel the film, too, only using the weaker blue foam to build-up non-weight-bearing landforms since I bought a couple of sheets for testing.

I use 2" pink in the 25 PSI rating ("Foamular 250") directly over steel framework. My adhesive preference for foam-to-steel is Gorilla Construction Adhesive. For foam-to-foam lamination to build landforms, I now use regular Gorilla Glue after trying Glidden Gripper primer paint. Gripper was tested by a stage scenery builder as "best" in a popular YouTube video, but I found it to have a problem with very slow cure rates on large laminations, with paint in the center still liquid even after a week. Made quite a mess when carving.

[Point353]

Besides, try finding Homasote at any of the big chains like Home Depot or Lowes, it's been long out of favor with construction professionals.

The Home Depot stores near me stock Homasote 440 SoundBarrier in 1/2" thick 4' x 8' sheets.
The product is identified on the HD site as "1/2 in. x 4 ft. x 8 ft. R-1.2 Sound Board Sound Barrier Sheathing".
https://images.homedepot-static.com/catalog/pdfImages/2f/2fb6a132-6378-4dd0-a12e-70aa6976310f.pdf
Menards is another stocking retailer: https://hw.menardc.com/main/items/media/HOMAS001/Prod_Tech_Spec/1631137.pdf
You check for other retailers here: http://www.homasote.com/wheretobuy

[MK]

When working with foam or gluing things to it, I use DAP water based adhesive caulking at Home Depot.  Under $4 for a sealable  tube.  Water clean up.  Get the clear one as it goes on white and dries clear.  You'll know when it's ready.

[C855B]

The Home Depot stores near me stock Homasote 440 SoundBarrier in 1/2" thick 4' x 8' sheets.
The product is identified on the HD site as "1/2 in. x 4 ft. x 8 ft. R-1.2 Sound Board Sound Barrier Sheathing".
https://images.homedepot-static.com/catalog/pdfImages/2f/2fb6a132-6378-4dd0-a12e-70aa6976310f.pdf
Menards is another stocking retailer: https://hw.menardc.com/main/items/media/HOMAS001/Prod_Tech_Spec/1631137.pdf
You check for other retailers here: http://www.homasote.com/wheretobuy

Thank you, I stand corrected. 18 sheets at our local Menards.

[MichaelWinicki]

I used 1" pink Styrofoam over 1/8" luan plywood in order to give "things" underneath the layout something to "grab" too.

Been solid for 11 years now in temps from -20 to 90 degrees with high humidity.

[dcarrell8]

Thanks, eventually I will post some pics of the project!

[MVW]

When working with foam or gluing things to it, I use DAP water based adhesive caulking at Home Depot.  Under $4 for a sealable  tube.  Water clean up.  Get the clear one as it goes on white and dries clear.  You'll know when it's ready.

I'll second the DAP caulk as an adhesive. You'll need a lot less of this than you'd expect. Run a thin line and then spread it with a blade. Use it sparingly, and you'll be able to pull up roadbed or track after it dries if the need arises.

I consider caulk almost a "temporary" adhesive. If you're going to ballast, the glue you use during that process is going to add plenty of holding power.

JTG

[jagged ben]

For anyone who just uses plywood, I'm curious how you hold down cork when gluing.

[wazzou]

For anyone who just uses plywood, I'm curious how you hold down cork when gluing.

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