How to Lay track on foam?

[dstarr]

   New layout in the planning stages.  Small, dismountable, in the guest bedroom.  When I have house guests it will pick up and store in the garage.  Garage is too cold for a permanent layout (I'd freeze) and I need it for the car in winter.
  Planning to do a foam board layout, that blue construction insulation.   "Styrofoam" is the trade name on the stuff I have lying around.  A wood frame of 1 * 4 pine for stiffness with the foam cut to size and set into the frames, with foam showing on the bottom.  (No plywood supporting the foam)  Sections held together with carriage bolts and electrical connectors.  Legs from 1 * 4 or 2 * 4 with plywood gussets to keep them from wobbling.  Legs removable for storage. Terrain features (hills and river valleys) formed by shaping the foam with a bread knife or a hot wire cutter.
   Questions.
1.  How does one lay track on the foam?  With laytex caulk like Phenoseal?
2.  How do you acheive the ballast bed under the track?  Lay cork road bed on the foam?  Cut the foam into a ballast shape with a hot wire cutter?
3.  How do you attach under table switch machines to foam securely enough to prevent them pulling out when they throw the switch?  Would a layer of 1/4" plywood under the foam work?
4.  Was planning to make my own hot wire cutter, a surplus 6.3 VAC transformer (or perhaps an old soldering gun)  and enough resistance in the nichrome cutter wire to keep the transformer transformer secondary current down to within the transformers ratings.

  Any thoughts or suggestions are welcome

[ARTHILL]

Good questions. I layed Woodland Scenics foam road bed on the styrofoam with clear laytex caulk. I then laid the flex track on the foam roadbed with the same caulk. I wieghted some and used track nails on the rest to hold it in place while the caulk dried.

There are other ways, but this worked well for me.

[Medina1128]

I laid out the track where I wanted it to go, then traced along the ends of the ties with a light brown Sharpie. Use a color that will blend with your final paint that you'll use for your earth color. If you use a black one, the black may bleed through. Once you have your track traced, apply a thin bead of acrylic caulk on a center line between the traced lines. The operative word here is thin. If, when you press your track into place, the caulk oozes up between the ties, it's on too thick. Once you press the track into the caulk, it will hold its shape (curves). I lay 4" wide strips on top of the track and place weights on top of that. This wil ensure your vertical track alignment. I like to bring my scenery base up to within 1/4"-1/2" of the rails, then paint it. Then I ballast the track. I find it easier to ballast the track AFTER the scenic base is in place. Remember, the ballasting on the prototype is on top of the surrounding scenery.

[abbieleibowitz]

First, you want the pink or blue foam, not the white bead stuff commonly called styrofoam. Technically, the blue and pink foam is called extruded foam. I use latex caulk and cork roadbed. I use the caulk to fasten the cork to the foam and the same caulk to fasten the track to the cork. It is possible to peel the track off the foam after it dries if needed. It doesn't seem to do much damage to the cork and the track is fine. Getting the cork off the foam after the caulk dries is a bit tougher, but also possible. I have fastened Atlas under table switch machines and tortoise machined to foam directly, but I use 1/4 inch plywood under my foam for this purpose. It isn't necessary for stiffness - the foam itself over the bench work is fine. I bought a hot wire cutter, so I can't comment on making one, but I use it only for finer work because it's too slow. I find that the most useful tools for cutting foam are a serrated knife, a keyhole saw, and a couple of Sure form rasps in different sizes and coarsness.

Hope this helps.

Abbie

[tomikawaTT]

Abbie, you forgot the Shop-Vac, probably the most useful tool of all when working with foam.

My base level is plywood.  I use thin foam (sold as fan-fold underlayment, for use under vinyl siding) and cut it a little wider than tie width, with sloping sides to simulate the edges of ballasted roadbed, before caulking it down.  Track is laid with grey (ballast colored) caulk, so thin spots in the ballast won't reveal the pink foam.  I pre-curve the flex to eliminate side stress as much as possible, and use track nails to hold the track laterally (they have no resistance vertically when driven into foam!)  Weight for freshly caulked foam roadbed or track is provided by lining up 2-liter bottles of soda on it.  (I have used a short length of 75# rail, but that is gross overkill!)

Where I use wood ties and spike the rails (hand-built specialwork) I use a layer of cardstock between the foam and the ties.  That, with caulk top and bottom, hangs onto spikes as tenaciously as if they had been driven into soft pine - adequate for my simple purposes.

So far I'm satisfied with the results.  If any problems surface, I'll report them in these forums.

Chuck (modeling Central Japan in September, 1964)

[Medina1128]

Actually, I've used the white beadboard foam with good results. I use acrylic caulk to glue layers together. I use a serrated knife and those razor knives that have the snap off blades to cut it (they have them at my Wal-Mart for 88 cents apiece, so I bought a bunch of them). A wire brush works well to shape the foam. I cover that with plaster cloth, followed by a thin layer of plaster. The advantage is that the white beadboard is a lot cheaper. And, oh yeah, tomikawa is right about the shop vac. If your shop vac has a paper filter, clean it regularly. That stuff clogs that filter up in no time. I found that I can brush the junk off the filter and reuse it until it starts getting holes in it. A vacuum cleaner needs AIRFLOW to work efficiently.

Try finding a Wal-Mart grocery distribution center in your area. I used to work at one and they get trucks from frozen fish vendors who used 4'x8' sheets of the stuff for load insulation. Most of the time, they just toss it in the compactor. Ask to speak to the Asst. GM or GM about getting some when they get trucks in. If you're nice about it, you can probably make arrangements to have someone keep it and call you when they get a load in.

[orsonroy]

As someone who's built six foam-based permanent home layouts (three for friends) and at least 30 foam-based Ntrak modules (most for others in my club) I've got a LOT of experience with using foam on layouts. Here's a few observations; take them any way you want!

   New layout in the planning stages.  Small, dismountable, in the guest bedroom.  Planning to do a foam board layout, that blue construction insulation.   "Styrofoam" is the trade name on the stuff I have lying around.  A wood frame of 1 * 4 pine for stiffness with the foam cut to size and set into the frames, with foam showing on the bottom.  (No plywood supporting the foam)

If you plan on moving the layout with any sort of regularity, do NOT just mount the foam in between a 1x4 frame. The first ten or so of my Ntrak modules were built this way, and the foam would ALWAYS break free from the frame in a very short time (one to three moves). My preferred method of building modules these days (and I'm working on four now) is a 1x3 frame base, topped with 1/4" Lauan or pine plywood, and covered with 1" foam. This gives you a more secure module overall while still retaining light weight and affordability (1x3s are cheaper than 1x4s, 1" foam is cheaper than 2", and the addition of 1/4" plywood doesn't absorb all of those savings). Best of all, if you can only find white beadboard foam in your area (a perennial problem for our Western modeler friends) you can still use it without worrying that the module will disintegrate.

Sections held together with carriage bolts and electrical connectors.  Legs from 1 * 4 or 2 * 4 with plywood gussets to keep them from wobbling.  Legs removable for storage.

I'd go with 2x2 legs with 1x2 cross braces. Cheaper, lighter, and as effective as what you're thinking of (and unless you're building a G scale home layout, there's NO reason to EVER use a 2x4 on a layout!). Build small boxes in the corners of the modules to act as sockets for the 2x2 legs, and you won't need any attaching hardware (and the 1/4" plywood acts as a stop for the legs, so they don't break through the foam top)

1.  How does one lay track on the foam?  With laytex caulk like Phenoseal?

Latex caulk will work well. I prefer latex caulk WITH silicone, since it grabs a little better (yet is still easy to remove if necessary). Mark your track centerlines, add the roadbed, sand the roadbed top smooth, add a thin bead of caulk to the roadbed, use a small trowel to smear the bead into a THIN layer of adhesive, and add the track. Use push pins to hold the track down firmly until the caulk dries (3 hours or so). Only work in sections less than 4' long at a time, since the working time of thin caulk is less than the drying time.

2.  How do you acheive the ballast bed under the track?  Lay cork road bed on the foam?  Cut the foam into a ballast shape with a hot wire cutter?

If you've only got a little track to lay (less than 100 feet or so total) Just use HO scale (1/4" thick) cork or foam roadbed. If you've got a LOT of track to lay (like I do; I think I've got 400 feet total to do) you may want to go with a cheaper alternative.

Cheap and traditional involves heading to your local Ace Hardware and buying 1/4" cork by the foot, and then cutting it into strips to lay like RTR roadbed. It's a bit more work, but costs less than half that of RTR roadbeds. for the edge profile, build up the edges using caulk, smeared into an angle with your finger.

Cheap and non-traditional involves using all foam. I've been cutting my own roadbed out of 1/2" pink foam, cutting it into 1.5" wide strips, and laying them like regular cork roadbed. To top it off, I use 1/4" pink foam, sold as long, narrow fanfolds. The cost is about 5% that of RTR cork roadbed, and the end effect is much more realistic than using cork, since you can get the proper stepped roadbed profile of the prototype. I hand cut the 1/2" foam edges into a proper profile, and use caulk to contour the 1/4" edges.

3.  How do you attach under table switch machines to foam securely enough to prevent them pulling out when they throw the switch?  Would a layer of 1/4" plywood under the foam work?

I don't use switch machines, but the 1/4" plywood under the base foam works well for this application. I use it to mount other stuff under the layout (lights, wires, a 1x1 to hold fascia, etc)

4.  Was planning to make my own hot wire cutter, a surplus 6.3 VAC transformer (or perhaps an old soldering gun)  and enough resistance in the nichrome cutter wire to keep the transformer transformer secondary current down to within the transformers ratings.

Don't bother. Hand tools work at least as well, are faster, don't emit poisonous fumes, are cheaper, and are easier to use overall. The nichrome wire will break on you constantly, progress will be agonizingly slow, and you'll eventually tire of the thing. Just get yourself a couple of snap-blade utility knives, a Stanley Surefoam rasp, a sanding block (coarse sandpaper), an old bread knife, a hacksaw blade, and a wire brush, and you'll have everything you need to carve foam. If you want fast & dramatic progress, chuck a wire wheel into a power drill (but be prepared to be covered in pink snow!). Oh yes: a shop vac is a MUST.

[mls1621]

I haven't tried latex caulk for track and can't justify it's use (personal preference).

I model in N scale and use white glue to anchor my cork road bed.  I then lay the track, using "T" pins to hold it in place(no holes in the ties).  I wire the track and then paint it.

I then apply ballast and glue it and the track at the same time.  Once the glue has set the ballast, the track isn't going anywhere.  I remove the "T" pins and the track work is complete.

I've also used this method on the last three HO scale project layouts for our local NMRA Division.  These layouts are two inch foam attached to 1" X 4" frames with adhesive for projects and foam.  We trim the perimeter with a luan facia.  For legs, we use universal folding table legs (I wouldn't do this for a home layout).  These are small switching layouts, 48"X80"(the size was determined so that it would fit in a mini van for transport).  The track is pinned directly to the foam, wired, painted and then ballasted.  No additional gluing has been necessary.

These layout gets moved to train shows throughout the year selling raffle tickets and have had no problems with the foam coming off the frame or the track separating from the foam.

My neighbor has his N scale layout in his garage, that does get quite cold in the winter, and we've used this same method as we've expanded his layout.

It's simple, it works and most importantly to me, we didn't glue the track twice when once was sufficient.

In this photo of my N scale layout, the mainline is on cork road bed and the sidings are mounted directly to the foam base.

The Workshop section of the April Model Railroader covers mounting Tortoise switch machines in 2" foam.

That's just one man's opinion, but it's worked well for me.

 

 

[reklein]

I use foam only for building scenery mass and not to lay track on. Not saying this is wong,its just the way I do it. Orsonroys method of applying the foam to 1/4 in ply sounds good,kinda like torsion box construction, but then a person could just use hollow core doors and go from there. The doors can be bought in different widths starting from 24" ,I think, but maybe they're too long for the module business.I also like the concise instructions for gluing down road bed and then track on the foam. Talk about light weight movable construction!!

[GT Mills]

I am also planning to move and need to keep things light while building a modular, somewhat portable layout.  I built a 3' x 4' module to start out with, it has a 7-stall roundhouse and 130' powered turntable.  That is 13/16" flooring plywood to give a lot of stiff support around the large turntable opening. 

My final design is complicated, 9' x 19', so to get up and running quickly I want to make a very simple, temporary loop that will incorporate the final layout's yard in the temp design, and figure on using 5mm plywood floor underlayment with a 1/2" thick sheet of insulation foam glued on top to deaden noise and add strength and rigidity w/o adding weight.  Only the yard & roundhouse modules will be re-used on the permanent layout, both of the loop ends will be torn up and recycled when I am ready to build more of the final design modules. 

[kasskaboose]

dstarr

   Questions.
1.  How does one lay track on the foam?  With laytex caulk like Phenoseal?
2.  How do you acheive the ballast bed under the track?  Lay cork road bed on the foam?  Cut the foam into a ballast shape with a hot wire cutter?
3.  How do you attach under table switch machines to foam securely enough to prevent them pulling out when they throw the switch?  Would a layer of 1/4" plywood under the foam work?
4.  Was planning to make my own hot wire cutter, a surplus 6.3 VAC transformer (or perhaps an old soldering gun)  and enough resistance in the nichrome cutter wire to keep the transformer transformer secondary current down to within the transformers ratings.

  Any thoughts or suggestions are welcome

 

 

1. Are you talking attaching track directly to foam or on cork sub-roadbed?  If the latter, I would suggest using white (Elmer's glue) to attach the foam.

2. Attaching ballast is easy with a 1" brush to spread the balast after putting it on the track with a Dixie cup on the track.

3. You can get piano wire from music stores.  I plan to do that.  Plenty of ideas here.

 

I suggest that you attach the foam and track with glue b/c that's easier to remove than caulk.

 

Good luck!

[BigDaddy]

kasskaboose

Good luck!

Necro thread alert.  David is still around, and if he hasn't figured out how to do it since 2007, I'm sure he will let us know.

[corsiar]

I have been gluing cork roadbed to foam board with PL-300. Been trying this stuff to glue the track to the cork and has worked well. Is always flexible and slightly tacky. Track comes up easy with a putty knife and dosent harm the cork.