I think I get how you get the benchwork plywood top curved, by using a jigsaw to cut the shape wanted. But it is the construction underneath and attaching the fascia that I am having conceptual trouble with.
Also, coved corners in a backdrop that is fastened to the wall where the benchwork is in a room and pushed up against the wall, but what of a free standing around the operator style benchwork.
For example, in MR, pg. 37 (Roanoke & Southern RR) and pg. 65 (Lost Island Bluffs Ry.) have curves in their benchwork tops as well as coved corners for the backdrops.
Coved corners where there is no wall to attach to: the best coved corners I have seen were done with sheet metal aluminum, and since it has a sort of natural curve to it I think the main idea is to firmly attach the two ends of the curve and let the natural curve of the metal take over. Once the natural curve finds itself, support behind it with sturdy extruded foam or wood to keep it from bending in any further, taking care not to create a dent or bulge. (Or maybe something “soft” yet unyielding like packing peanuts or rolled up newspaper?)
I also saw very plausible coved corners where the guy had taken the large inner carboard tube from a roll of carpet and cut it into not quite half, lengthwise. It holds the curve all on its own; a tighter curve than most coved corners but still better than a 90 degree angle. I suppose even round downspouts if precisely cut lengthwise would hold a curve. Have not seen that done however.
For the fascia, I have seen layouts featuring the L girder style where the girders were of greater lengths so the outer edges followed the sweep of the layout, and the Masonite or hardboard fascia was screwed onto the end edges of the girders. (perhaps also the edges were themselves shaped and rounded?) Within reason there is a natural curve to Masonite. Try bending it too far and … crrrrack.
In the photo below you can see the grid bench and the plywood and the foam. The bench is 1x4s all put together with Lap Joints. Some of the 1x4s are doubled up to make 2x4s in spots where I thought extra strength was warranted. Also by using two 1x4s to make a 2x4 they tend to keep each other in check as far as warping is concerned. The bench is 6 x 18 FT. I wanted the round end as you can see so what I did was put 1/2 inch plywood on top and grab my home made trammel and marked the half circle. I then cut out the half circle cutting through the plywood, 1x4s and all. There are lots of spots to screw the fascia to. I used a circular saw to cut it as the diameter was large enough. A jig saw would also be a good choice.
I put 2" foam over the grid and used 1 1/2" foam on the 1/2" plywood so they would match in height.
I wouldn’t be to fussy with how the benchwork looks as it will all be covered eventually with scenery anyway. Build it sturdy so it doesn’t flex. That’s why I chose Lap Joints for my grid. How I would build it would depend on size and and trackplan and scenery wanted. I am a firm believer in the “there is more than one way to skin a cat” camp.
In the photos below it shows my backdrop. I used masonite ( hardboard ) mounted to the 1x4 benchwork. I used 10/32 machine screws and “t-nuts” so I could easily dismantle it if needed. I also used them to join all my benches together.
I cut out 3 1/2 inches at the appropriate spot and curved the backdrop over the bench. The backdrop is freestanding and I have had no issues with it thus far.
I glued a 6" wide piece of masonite on the back at the joints and filled the seams between the pieces with Dap as you would when drywalling a house and they are invisible to the eye.
Over in the General Forums is a thread “Backdrops,” by Handorf. Sorry I don’t know how to refer you to it directly. It has a lot of information I think you may find helpful.
As well as masonite, sheet styrene, aluminium flashing (can get it pre-painted) and a new(?) product called Dura Flash can be used.
Most of the backdrops I have seen made from these products are glued to verticle posts, thus no nails or screws to hide. The flashing and Dura Flash come in long rolls, eliminating the need to have seams to hide.
Given the proper tools and techniques, even a piece of solid wood can be made to curve. The table in the photo below was framed with 1x4 poplar. I cut kerfs in the backside of the wood and formed the curve, then attached the tabletop.
When forming a serpentine fascia, the key is to have fairly tall rigid vertical attachment posts, so the fascia material (mine is Masonite) will only bend in the horizontal plane. My fascia posts are screwed to the joists of my L-girder benchwork, which are cut off a varying lengths, allegedly following the edge of a mountain river.
Another possibility for a coved corner backdrop is to use a section of cylindrical concrete form. The forms come in larger diameters than carpet rolls, and are made of heavy cardboard wound in spiral fashion. I never did cut one lengthwise (I was pouring footings for a heavyweight deck) so I don’t know how durable they would be, or how easily they might deform. I’ll have to get one and find out - I have two corners which will require concave curved backdrops/scenery bases.
Sorry for the delay in responding…I don’t stop in here very often since I tore down my layout in July 2009. I cut the kerfs on my tablesaw…many, many kerfs. The end results were well worth the extra effort and work.
Both curved backdrop and fascias can be easily had by using 1/8" or even 3/16" Masonite attached tot he wall or bench work. The key is to attache the backdrop mounting piece directly over the top of the wall and not try ti ingrate it with existing drywall. a hard lesson learned. Start of course in the corners first and if you have something to use as a template to gage the radius size thats usually helpful but not necessary. If you take a length i would say no shorter then 4’ and make a mark down the center place the center line in alignment with the corner of the wall. With the help of a friend hold the piece up and push the center line towards the corner of the wall and have you friend screw in one end. NOTE: mark the location of your studs so it doesn’t resemble an Abbott & Costello movie trying to hit a stud with your dry wall screw. Once you’ve established you curve working outward form both sides is easy. When it comes to doing the same on bench work I’ve found spring clamps to be very helpful. I also used a countersunk drill made for doing drywall so the heads of the screws are just below the surface of the Masonite. a little drywall compound and things are seamless.Painting the backdrop mounting piece the same sky blue color as your train room is also a good idea.
If your someone who plans your railroad better then I have and you know what backdrop you want where be it city,rural farm, industry etc.it’s best to put them in place before your bench work even goes up.Working right in front of something is far easier then leaning over how ever wide your bench work is going to be.
Making outside curves on your fascias is pretty much the same thing in reverse but it can vary a little depending on what type of bench work your using.
Below you can see where i bent a couple of parallel spline to make an outside curve and eventually attached luan to the splines making the curve. It has since been replaced with 1/8" Masonite which worked out much nicer.
I guess I’m lazy - all my benchwork is square. Inside curves, the fascis will curve, no problem doign that without special benchwork formation. Since my layout is around the walls, I only have one point of an outside curve, at the end of the penninsula for the cement plant. Since that will make 2 sharp points that could hurt if you walk into them, I will likely bevel the end pieces of the framework to 45 degrees, and the fascia will have a bit of a curve around it. I don’t think any special additional supports will be required for this.
While I have no experience with free-standing backdrops, creating coved corners in a dedicated train room is easy if the walls are first properly constructed. My layout, a mostly around-the-walls style, is in its own room in the basement.
I drywalled my layout room by installing the sheets vertically in order to make full use of the tapered edges for finishing, using 1/2" board for the majority of the room, but substituting 3/8" at all corners, both inside and outside. The 3/8" board should extend for at least one full stud spacing on either side of the corner. Tape and finish all joints as you normally would, except those between the two different thicknesses of board.
While the room was “boarded” as-described, the coved corners extend only from the top of the layout benchwork to the bottom of the suspended ceiling. To form the corners, place a tape measure in a rough arc from the edge of the 1/2" board on one side of the corner to the edge of that on the other side - the arc described should be roughly similar to what you wish the finished cove to be. Working from the back (rough side), cut a sheet of 1/8" Masonite to the required height and the length thus obtained. Lightly sand any fuzz from the cut edges, then place the back face of one vertical edge of the piece against the 3/8" drywall, butting its edge against the adjacent 1/2" piece, then press, top and bottom, on the Masonite. It will bend with the pressure, forming an ever tighter curve, until the free end “pops” into place on the adjacent wall. While this curved piece will hold itself in position, I drill and countersink for drywall screws along both sides, spaced fairly closely, in order to prevent movement or bulging due to humidity changes within the room. Mud and tape the joint as you would any other. Outside corners are handled in a similar manner, although I’ve found that a wider area of 3/8" drywall is preferable. This lets you begin the cove as a regular conca
If your room wall is your backdrop and you want to curve the corners you could try this technique. On a home remodelling show I watched on TV, the contractor was building a curved, semicircular ceiling (I think they called it a barrel ceiling) in a hallway. They wet the back of the drywall sheets until the paper backing and the gypsum interior became soft. Then they held it up to the ceiling and and pressed it up against the curved support structure then screwed it into place. Apparently after softening the drywall sheets they had to hurry to get them into place before they started to dry out again, and the sheets looked pretty floppy as they were carrying them into place. I don’t recall if they used a full half inch thickness of drywall or something thinner. I would think it would take some experience to know just how much to wet the drywall before it becomes mush.
I used common wood paneling to make my fascia. I ripped it to the necessary widths on my table saw. I then clamped them to the layout, lining up the bottom edges with each other. I traced the shape of the landscape to the paneling from the layout side. I took it down, cut it to shape with a jigsaw, then sanded the cut edge. I used flathead screws, after countersinking the holes to attach it to the layout. Paneling will bend to some pretty tight turns. A little plastic wood along the seams hides them pretty well. Now, that I have it done around the layout, it’s time to settle on a color to paint it. I was leaning towards a forest or hunter green, but after reading other posts, I may go with a dark, satin finish brown.
