I have read the comments in another post series about using rigid structural foam molding as a base and for scenery for my HO Gauge RR. I have the following comments and questions:
1. I have obtained 2" thick white structural foam in 4x8 sheets from a local extruder. He has told me that the density of the material varies inversly with the size of the individual plastic beads used in the extruding process.
2. I plan to use the 2" thick material as a base cover over 3/8" plywood so that I can carve out depressions. At HO scale, 2" thickness represents 14.5 scale feet of thickness, which is enough to justify bridges over water features without having to cut into the plywood.
3. I plan to use the 2" thick material to build up scenery and elevate sub-roadbed.
4. I plan to use Woodland Scenics foam roadbed under the track.
5. I plan to avoid use of any glue (a major departure from conventional wisdom, I know).
6. I plan to secure the base foam to the plywood, using nails long enough to penetrate the foam and the plywood. I hope to find that there will be sufficient lateral stength and memory to secure the foam to the plywood.
7. I plan to use 1" long 18GA Wire Nails to secure track and foam roadbed to the structural foam. I nmay use 1.5" long 18 GA Wire Nails, if I elect to purchase them from a mail-order manufacturer I have located on the web - so far, I have not found 18 GA nails longer than 1" elsewhere. Again, I am expecting sufficient lateral retention from the nails, without the need for glue.
8. I am avoiding glue all around in order to facilitate changes or corrections as I go along.
I would appreciate comments from modelers who have had exxperience using this material and, especially, comments from anyone who might not have used glue.
Regards to all,
Art
Are you referring to EPS foam or blue styrofoam insulation (yes, I know you said white in color but you also said "styrofoam")?
If this is foam that's traditionally used for exterior wall insulation then I highly doubt you would be able to get 1" nails to stay in place to hold the track. The material density is nowhere near that of wood or even homasote to allow sufficient grip. It may appear for a time the nails hold but if for some reason you remove a nail, re-insert or "wobble" it even a slight bit in the hole any fastening effort will be lost.
Even in home/comercial construction it's not allowed to use the foam to structurally hold siding or trim. There has to be a wood underbase to nail into.
Now, if you can get 2 1/2" long 18ga nails you'd be in business.
Just my thoughts.....
-G-
I wouldn't consider white "beadboard" as "structural". I personally wouldn't use that for anything but scenery base. The strongest foam is the "blue" or "pink" foam that is a solid block of foam, no beads whatsoever. It is much more rigid and somewhat harder, resisting pressure and denting more. A tad heavier, but not significantly.
The white beadboard doesn't cut as smoothly and shreds into those little beads that stick to everything (used drier softening sheets are great to wipe off tools and surfaces, the anti-static in the drier sheet "unsticks" the beads). The white board is waaaaaaaay messier than the blue or pink variety.
As for glue, white glue (Elmers, Titebond) or latex adhesive caulk are safe on foam. Silicone caulk will work but it is more or less permanent and will stick to ANYTHING it touches with virtually no chance of removal. Latex caulk can be removed with a little work. Latex or acrylic craft paints are good on foam. Conventional spray paints, laquers (Diosol based Floquil) and thinner based enamels are death to foam. As are soldering irons.
Dave H.
Dave H. Painted side goes up. My website : wnbranch.com
Thanks to both of you for providing more information about different types of rigid foam. I have looked at both Pink and Blue foam sheets and I agree that there is a definite difference in density between either the blue or pink and the white materials. I can obtain the pink foam locally from Home Depot, but it is expensive ($27.50 per 4x8 sheet for 2" thickness versus $2.00 per 4x8 sheet for 2" white foam). I will need a total of 7 sheets to cover my table surface, so this cost delta is significant for a retiree.
Do either of you think that using 2" thick pink foam instead of 2" thick white foam will permit me to successfully mount roadbed and track using just 1" or 1.5" 18 Gauge Wire Nails (no glue)?
I have experimented with a small piece of 3/4" thick white board and 1" nails - the roadbed and track seem to remain in place even when I apply significant lateral force. I realize that vertical shifting will dislodge the roadbed/track and I also understand that removing and reinserting a nail will reduce the amount of "grip" in that location.
If the foam is not suitable as a surface for the roadbed and track, what readily obtainable and less-costly material would you recommend? I really want to avoid a lattice-work table structure and I really want to find a material which is easily cut and altered.
Thanks again,
Where are you getting 4x8 sheets of 2" white foam for $2??? I need some of that to insulate my train building.(that's about all I would use that stuff for)
It's OK to cut into chunks to be used as mountains and such,(then cover with plaster cloth) but not a good idea for the whole base. I know the cost thing stinks, but it sounds like your building a pretty big layout and that's a lot of regret down the road.I'd think twice about the WS foam roadbed too. Cork all the way for me!
ArtDaniels wrote: I can obtain the pink foam locally from Home Depot, but it is expensive ($27.50 per 4x8 sheet for 2" thickness versus $2.00 per 4x8 sheet for 2" white foam).
Youse gets whats youse pays for.
I made a layout for my son using blue foam. I used small nails to hold flex track down. My experience was that after time the flex track attempted to straighten out and the nails didn't hold it. If didn't get loose, but I could tell it shifted at joints, etc. White foam would be weaker still.
My recommendation if you had to use white foam would be latex adhesive caulk.
If the foam is not suitable as a surface for the roadbed and track, what readily obtainable and less-costly material would you recommend?
Less than $2 a sheet? Dunno.
Beadboard can be used. Just on the scale of best to worst material, it has many drawbacks (described above). I personally wouldn't use it as a base material (if I had room for larger radii and more layout I would be doing Homasote spline, I am currently using Homasote on 1/2-3/4 plywood) and I wouldn't rely on nails or pins to hold the track if I did use beadboard.
7 sheets? That's no small layout. As for the cost of the blue board, that's the same as most good locomotives theses days. But you could use thinner sheets of foam board. As for the glue use latex caulking. A thin bead works great. And to remove it just use a thin knife run alone the plywood or a guitar string. Either one of the three will not hold nails but latex caulking works great at holding the track work in place once it cures.
BTW "StyroFoam" is formed into beads first, then into the board form. While blue or pink foam board is formed into boards as it is excreted and has air in it.
Johnnny_reb Once a word is spoken it can not be unspoken!
My Train Page My Photobucket Page My YouTube Channel
Again thanks to all who responded to my second post on this matter.
Johnny Reb offers a good thought, but I want to be sure I properly understand his approach.
There are two issues - mounting the 2" foam to the subsurface as a base surface and mounting foam roadbed and track to the 2" foam.
Are you suggesting that I use a bead of latex caulk around the edge of the 2" foam to mount the foam sheet to the subsurface? I like that idea.
Are you also suggesting that I could use a bead of latex caulk to secure the edge of the Woodland Scenics foam roadbed to the foam surface and perhaps then securing the track to the WS roadbed also by using a bead of latex caulk? If so, I also like this idea, especially since I can see that removing the foam roadbed and track could be easily accomplished, in the inevitable event that I make changes.
As for the $2.00 price for the 4x8 sheets of 2" foam, I live near a manufacturer of rigid foam insulation and he has sold me a few "seconds" at this low price. Otherwise, I'd be at Home Depot like everyone else.
I have the lumber for my second 4x16 table and when I have the table assembled, I plan to experiment with the 2" foam and foam roadbed/track to see what results. Part of the fun for me is looking at novel ways to accomplish my objectives. For example, I have some 2.5" coarse drywall screws I plan to try out for mounting the 2" foam to the plywood subsurface.
Best regards to all,
Art,
My entire layouts depend on this foam. It's easy to carve for mountains and valleys. Covering the foam with a few coats of Durham's water putty will texture the foam and the beads will vanish entirely. Also, It makes planting trees easy since the core is solid.
Here's a few shots of mountains in various stages...
New carving I'm working on...
Applying water putty and color...
Finished products...
Art, for your 2 1/2" screws in the foam.....pick up a bag or 2 of body washers with about a 3/16" hole. Run a screw thru the washer, thru the foam and into the plywood. These are about 3/4" across and will supply plenty of load bearing area to the foam. Our local Lowes has these relatively cheap. Just sink the screw head slightly below thw foam surface.
Before I paneled my basement walls I attached 1" blue DOW foam to the block wall in the same manner using 2 tap-con screws each. This held the foam in place while I studded the walls.
concretelackey wrote:Art, for your 2 1/2" screws in the foam.....pick up a bag or 2 of body washers with about a 3/16" hole. Run a screw thru the washer, thru the foam and into the plywood. These are about 3/4" across and will supply plenty of load bearing area to the foam. Our local Lowes has these relatively cheap. Just sink the screw head slightly below thw foam surface.Before I paneled my basement walls I attached 1" blue DOW foam to the block wall in the same manner using 2 tap-con screws each. This held the foam in place while I studded the walls.
Another option are fender washers. They are even larger in diameter (1 1/2" or more) You can get them at auto part stores.
Johnnny_reb wrote:7 sheets? That's no small layout. As for the cost of the blue board, that's the same as most good locomotives theses days. But you could use thinner sheets of foam board. As for the glue use latex caulking. A thin bead works great. And to remove it just use a thin knife run alone the plywood or a guitar string. Either one of the three will not hold nails but latex caulking works great at holding the track work in place once it cures.BTW "StyroFoam" is formed into beads first, then into the board form. While blue or pink foam board is formed into boards as it is excreted and has air in it.
For info: "Styrofoam" is the trade name for the blue board, not the beadboard.
Perry, I find your construction photos very interesting. The first one looks like someone went nuts with a very large can of shaving cream. But, the finished product is outstanding. I am very impressed.
One question? What is your base under-layment?
Dante, my local Lowes store calls it "insulfoam". But what ever it's called I plan to use it as the under-layment for my layout. And after seeing Perry's construction photos I will be using Styrofoam for hight over the insulfoam or plywood under-layment.
I used inexpensive 1/2" plywood from Home Depot for the tunnels/core. Here's a short slide show (14 pics) if you're interested in viewing my process.
http://home.mchsi.com/~ironmaster1963/wsb/html/view.cgi-photos.html-.html