I hope I describe this well. My mainline rests on 3/4" plywood "ribbons" supported by risers screwed to joists--classic L-girder construction. Topographically, the mainline follows (as in many prototypes) a stream, which will flow along roughly 25 scale feet below track level. (I've managed to provide a clear path for the streambed "through" the joists.) How would you support the streambed? What would you use to make it?
So far, I'm thinking of making a trough of cardboard webbing. One edge of the trough would be attached with staples and hot glue to the edge of the mainline's plywood subroadbed; the other edge--the top of the opposite bank--would be similarly attached to the edge of whatever scenery is there, which will be built atop a layer of thinner plywood.
The low point of the trough would be flattened out and a ribbon of 1/4" Masonite laid in, as narrow as the stream bottom needs to be for a realistic slope to the banks. Then I'd add plaster gauze to the bottom and sides/banks, and a layer of lightweight Hydrocal over it to seal everything, and then the scenic materials: paint, gravel, plants, and one of the standard "water" products.
I'd welcome alternative methods, warnings, additions, or other advice. Thanks.
I use foam myself, but my layout is built on a foam base.
Make sure your streambed is flat and completely sealed. My "water" is Envirotex Lite, which will find small leaks and drip through them, and will settle at the lowest points. You don't need a lot of physical depth. The illusion of depth is done with darker paints and tinted "water." If your stream has a slope to it, either intentionally or not, consider terracing it with short sections of rapids, a dam or a waterfall between flat sections.
It takes an iron man to play with a toy iron horse.
What I usually do is to build a river bed out of plywood, hardboard, or some other material, and install it on risers just like roadbed. This gives me something solid as a base. I can then establish the remaining contours around it.
Rob Spangler
That's pretty much how I constructed my Hammer Creek.
I use the same method Rob uses -- the banks are supported by the stream bed, rather than the stream bed being suspended by the banks.
I'm leery of depending on cardboard for support the way you describe. It's going to be hard to ensure it's sealed. Most scenery methods depend on a certain amount of "wetness" via water and that tends to diminish the strength of the cardboard. Likewise, I suspect the cardboard will be subject to flexing, which may cause whatever you use for water to crack or distort.
Note how Grampy did his. With the solid base, the cardboard, plaster, etc are supported by the benchwork, rather than suspended from the scenery.
Mike Lehman
Urbana, IL
I'd use plywood for the river bottom and build up the sides with foam, zip texturing, cardbooard strips and plaster cloth, screen or some other method.
Victor A. Baird
www.erstwhilepublicatiions.
You should use a couple of small scrapwood blocks with something either hot glued or wood glued between them, whether plywood or aluminum window screen. I suspect there will be a bridge there supporting rails? Then you already need something to support the bidge abutments, and you'll need something near that to support the sub-roadbed. All-in-all, you will find yourself crafting some kind of framework to support both the scenery and the roadbed/tracks. You might as well include something to support your riverbed at the same time.
I have plywood on my latest layout, but used the hot glue and appropriately sized swaths of aluminum window-screen because I used ground goop terrain on my previous layout.
I do the same as the plywood guys only use masonite. It provides a great flat bottom to build up from with a lot of the depth illusion coming from paint.
The flat, solid streambed seems to be the clear winner. So let me add another reason.
With a solid bottom under the kawa* you not only have a strong foundation for the banks, but a nice surface for modeling the sandbars, projecting rocks and other features of a watercourse that goes from lazy meander to flash flood. Then, when adding water, the use of that material is minimized - just enough to have everything look flat and wet.
If you want to add one of those 'mini-waterfall over a ledge' features, just let the upstream bed overlap the downstream bed at a joint.
My watercourse surfaces will range from perfectly flat behind a dam to raging cateract rushing down the mountain on a staircase. In all cases, the sub-bed will be a perfectly level (bank to bank) hard, straight object.
* Kawa - a japanese character, roughly ///, translated as moving water, that can mean anything from a rain ruvulet to the mighty drainage for half a continent.
Chuck (Modeling rainy Central Japan in September, 1964 - with plans for lotsa kawa)
Masonite with the shiny side up does make a good base for paint, etc on the stream bottom. Gotta be cautious with wider bodies of water, as you could end up with "ripples" when the masonite swells or shifts with humidity etc. One way to obviate this is to use both a "sub-streambed" of plywood, then going over it as part of the scenery process with a masonite streambed. The best of both methods
I think what prompted me to ask my question was a hunch that these would be the sort of responses, so I'm feeling confirmed by all these helpful (and fast!) replies. Yes, it looks like a little more effort, but I know I won't be sorry. Thanks to one and all--and to Chuck, domo arigato gozaimashita.
Michael
I am also in the 'banks supported by the base' camp. I build a light weight frame which is leveled and attached to the benchwork and then attach a plywood base to this frame onto which I also attach red building insulation. I make the base a litlle oversize to make room for the banks which are cardboard strips covered with plaster cloth and sealed with some additional plaster where the banks meet the base. Maybe it's a little overkill but I have never had a leak and once it's level, everything works just fine.
There's never time to do it right, but always time to do it over.....
Maybe I don't have the picture right, but presumably you didn't cut all the way through your joists to make the path for the stream. Use the remaining width of the joists to support a piece of 1/8" hardboard.
Connecticut Valley Railroad A Branch of the New York, New Haven, and Hartford
"If you think you can do a thing or think you can't do a thing, you're right." -- Henry Ford
The riverbed on this small diorama was made whith gator foam, it's so easy to use and fast to do, I highly recommend it. This is Nscale
All the pieces were glued like a stairs to model the chutes and glued with a hot glue gun.
The picture show the riverbed not readily glued on the base.
Gator foam can be painted whith paint and support any scenery materials, including water resin.
See the pictures, they explain more than I can...