DoughlessI'm still going to head to the local HD just to see how dense or fragile the tiles actually are.
How about applying diluted carpenters glue to the tiles. They apparently are absorbent according to all the water stains I have seen in ceilings over the years. I'm not sure how much weight that would add, but the goal would be to form a stronger bond between the fibers, not fill all the voids. I would use a glue that is water resistant so that the tiles don't go soft when you are doing scenery.
Just a thought. Might be worth an experiment. I would do any carving or shaping before applying the glue obviously.
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
I hadn't thought about the water absorption much or swelling. I suppose once the moisture evaporated they would shrink back to near normal shape. Residual undulation may be a benefit if using tiles in a mostly rural scene, a bit of a pain if its under a buidling.
- Douglas
Like I suggested, time for an experiment.
The Redstone Model Railroad Club used ceiling tiles over plywood in our main yard and engine facilities. NOT a good idea! Fasteners of all kinds pull out. Corners break off at the slightest pressure. Pull up glued-down track and half the tile comes up with it.
Carl Neste
Checked out ceiling tiles at the local big box and bought some. They were denser than I thought. Pressed my thumb against them and the pink foam and the tiles took more effort to dent than the pink stuff.
Got them home, come in a shrinkwrapped box. I noticed that if you set them down by just letting them drop out of your hand over a foot from the floor, their weight will probably dent the corners. A little precision is advised.
I'll be installing them on 22 inch deep shelves, and the plan was always to neatly trim out the front with 1x stock, so the edges will be protected.
Now its a matter of finding some roll on/brush on adhesive to make the plywood a flat tacky surface to set them on.
Up dating the thread:
I finally got to the point of installing the ceiling tiles over the plywood in the staging/interchange area. Overall I'm pretty satisfied with them. Ended up being 20 inches deep because of some restrictions in the room.
Tiles need to be cut with a jigsaw, as a carpet knife just tears them more than cuts them.
Dusty stuff. They are pretty dense. I didn't have any problems handling them. They crush if dropped on the corner, but are dense enough to hold their weight well if handled horizontally.
By all accounts, they seem to be not much different than Homasote.
Used 1x boards as facsia. The ends could get crushed or crumble if not protected by fascia.
I screwed them down instead of using glue. Of course, care must be taken to not screw through them entirely with the coarse threaded drywall screws I used.
My plan is to caulk down roadbed on top of the tiles, then paint all of this subroadbed before poking holes in it with trees.
Overall, I don't know if using tiles, or anything else laid on top of the plywood, presents a clear advantage for track laying. I think it will work well for scenery outside of the RR ROW.
Don't know if I'll bother with it for the rest of the layout as a subroadbed material. No real problem, just a step that's probably gives no advantage. Roadbed laid directly on 3/4 inch plywood seems like the way to go.