Designing and Building with Styrene
Designing and Building with Styrene
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This article shows you how you can design and construct
large scale buildings using inexpensive industrial styrene sheet.
It uses a cabin for illustration, but the methods apply to buildings of
any size.
This article is written mainly for modellers who are new to scratch building. Experienced scratch builders are also welcome to read it for the new ideas it contains. In this article, the author leads the reader step by step through all the processes needed to design and construct a small building in Large Scale. The explanations go into far more detail than would be possible in a printed publication. While a particular building has been used for illustration and could be copied by the reader, this article is as much about how to design your own building as it is about duplicating someone else's.
The cabin at left, only part of which is shown, was built entirely of flat sheet styrene except for the wood pile, which was made of old, dry Choke Cherry branches. The siding looks like drop siding because it is drop siding, made of flat styrene. The shingles look like shingles because they are shingles, made of flat styrene. And the window looks like a double hung windows because it was modeled to look like a double hung windows, but it too is made of styrene. Total cost, including paint, was only about $10, and that's Canadian dollars, folks. The time required for completing a building using the methods outlined here is not much greater than for completing a similar size kit. But the satisfaction of being able to say "I built that, and I built it just the way I wanted it" is infinitely greater. Maybe before we start, a few words on sizes would be in order. Many workers prefer to work in scale feet and inches. Scale rulers are now available commercially for almost all large scales. One manufacturer is Scale Card. The alternative is to use real inches. The sizes shown here are based on 1/29 full size but are rounded off to convenient fractions of real inches, in case you do not yet have a scale ruler. Workers in scales larger than 1/29 are welcome to increase sizes a little. Modellers who have not worked with styrene before, and even those who have, might want to jump to Working with Styrene before proceeding further. Most buildings, scale or full size, are basically a box or a series of boxes. These boxes have flat tops, sloped tops, rounded tops or even pointy tops, called roofs, and usually have one or more openings, called windows and doors. Sounds pretty basic. It is pretty basic. And they are easy to build. The first step is to decide how big the box should be. In the real world, buildings are often as large as we can afford to make them. In the scale world, it is more likely a matter of how much room we have for them. If size were no object, we could just scale down buildings that appeal to us, or design them to suit our purpose (if you want to build a 20 actual foot engine shed to store a whole train in, and you have the room, go for it.) If size is a problem, for example squeezing just one more building between track and fence, then cheat a little. Make a model of a small building, make a slightly undersize model, or even squeeze the model in one direction to make it fit. (I cannot recall any real world buildings that are 20 feet high, 40 feet long and only 2 feet wide, but still I have no qualms about making background buildings that are only 1" thick.) You will have to decide on the size of your building for yourself. The cabin shown in the photograph above is a box about 6" x 8" x 4" high at the eaves. The size was dictated by the room available on a portable layout. In 1:29 scale, it is about 15' x 20' x 10', roughly the size of a single garage, and believable for a cabin in the woods. Scott Gibb's CN station, pictured elsewhere on this site, was built using similar techniques and is full size for 1:29 scale. The basic box may be made of plywood and clad with styrene, which gives a heavy (read wind resistant), rigid structure or it may be made of styrene alone (light weight, rot proof). The cabin was made entirely of styrene. Once the length and width were decided, the next step was the height. Typical height for a house is based on an 8' ceiling plus a bit more for the above-ground part of the basement. (note to Californians - "basement" is a kind of cave under the house, otherwise known here as "the train room"). For reasons that will become clear later, it is convenient to have the top of the basement wall an odd number of eighths of an inch below the eaves. 3-3/8" is convenient, and close enough to 8 feet in 1:29 scale. Adding another 5/8" for foundation gives a convenient 4" for the side walls. This is a reasonable height for any single story house. For the cabin, the side walls were cut 4" x 8" out of .060" styrene. The end walls of the cabin include gables for the roof. The steepness of the gables varies directly with the age of the building and so provide a visual clue to the period of its construction. The cabin is supposed to be early 1900's, so its roof has a relatively steep pitch. For convenience, the pitch was made 1 in 1 or 45 degrees. Why was this convenient? Firstly, the calculations were easy. With 45 degrees, the rise above the line of the eaves is exactly 1/2 the width of the walls. Therefore the overall wall height is 4" (to the eaves) plus 3" (half of the 6" width) = 7". Secondly, with the halves of the roof meeting at 90 degrees, any scraps of styrene with a square corner could be used as roof braces. Two cabin end walls were cut 6" x 7" out of .060" styrene. Then the roof lines were drawn by measuring 4" up from the bottom along each end of the wall, making a mark, and 3" across the top to find the top center of the wall, and making a mark. Using these marks, two scrap triangles were cut off each wall, and saved for later use as roof braces. The top and bottom of the basic box are the floor and ceiling of the finished building. These are necessary to stiffen the building and keep it square. The ceiling and floor will have to be a little smaller than the walls to allow them to be set in. If we set the side walls of our cabin inside the end walls (the diagram under ASSEMBLY shows this) then we must make the floor and ceiling narrower than the end walls by two wall thicknesses (1/8", which is close enough to 2 x .060" for our purpose.) For the original cabin, the floor and ceiling were cut 5-7/8" x 8" out of .060" styrene. While we are in the business of cutting styrene, we can cut the roof. The roof consists of two pieces, which should overhang the walls by about a scale foot. This means adding about 1" to the length, to allow 1/2" overhang both front and back, and about 3/4" to the width, to allow 1/2" overhang on one side at 45 degrees. The width of the roof can be calculated, but measuring along the gable angle of the end wall is easier. On the original cabin, that slope measured 4-1/4" inches, and the roof halves should be (8" + 1") = 9" long by (4-1/4" + 3/4") = 5" wide. To allow for overlap during assembly, one piece should be cut 1/16" wider. Therefore one piece 5" x 9" and one piece 5-1/16" x 9" were cut out of .060" styrene. This would be a good time to mark the pieces to show where you apply the siding and shingles. For 3/8" shingles as used on the cabin, you can draw lines parallel to the eaves, every 3/8" measuring from the eaves on up. It will not come out even, but that does not matter. For the walls, draw lines parallel to the eave line every odd eighth of an inch, that is, at 1/8", 3/8", 5/8" etc. from the eaves. Quit at 3-3/8" down. As a check, the last line should be 5/8" above the bottoms of the walls. On the gable end, continue drawing parallel lines working up from the eave line, again at every odd eighth of an inch. Whew! A whole lot of words just to cut and mark 6 little pieces. However, by now, you should be able to design and cut the pieces to make the basic box for many different buildings, and mark them out for applying shingles and siding. Now before you assemble them, it is time to put in the windows and doors.
It is easier to cut the holes for the windows before assembling the basic box. If you have visited Working with Styrene then you already know how to cut and deburr the holes. The only question is where to put them. It is convenient to have the tops and bottoms of the window and door holes fall on the lines you drew on the cut pieces. Just why this is so will become more evident when we get to the section on siding. The tops of traditional double hung windows are typically 1' to 1-1/2' below ceiling or eave height. This is close enough to 5/8" to put the tops of our windows at that mark. Double hung windows are typically about 4' high. This would put the bottoms of our windows conveniently at the 2-1/8" mark. This is shown in the diagram at right. Some of your windows might be less than 4 scale feet high. In the early 1900's it was considered good design to align the tops of all the doors and windows, so for shorter windows, moving the bottom up is better than moving the top down. Double hung windows are usually narrower than they are high. With this in mind, the cabin windows were arbitrarily made 1" wide. Not visible in the photo of the cabin is one window built double wide. It is two windows, each 1" wide, with a space of only 1/4" between them. This also was fairly common at the turn of the century. Now that you know where your windows are going, you can cut the holes and deburr the edges. The doors should extend from window top height down to the floor, which is at the 3-3/8" mark in the original cabin. This leaves a door height of 2-3/4" which is smack on 6'-8" scale height in 1:29 scale. Door width for a small building might be 2-1/2', but could be up the 3' that is more common in larger houses (commercial buildings often use doors closer to 4' x 7'.) The doors in the original cabin were arbitrarily made 1" wide, which is just shy of 2-1/2 scale feet. Cutting holes for the doors is optional. Holes are of course required if the door is going to be mounted in the open position. In the author's part of the world, doors are kept closed in the heating season and rarely opened in the air conditioning season, so only the occasional model is made with an open door. At this stage, all that is required is to mark the positions of the doors. Add 1/8" to the tops and both sides of the doors to allow for trim and draw them directly on the walls. The original cabin has only one door, on the end opposite the shed seen in the photo. With the holes cut and deburred, it is time to make the windows. This
is the trickiest part of the whole operation. The procedure is covered
in detail in the article Large Scale Windows and
Doors.
Assembly is mostly a matter of keeping things aligned while the solvent cement or the glue sets. Adding corner blocks can help considerably, as well as making a stronger final product. These blocks, shown in the diagram at right, are installed first, before the inset pieces are added. You can use 1/8" square styrene strips, which are very convenient, or you can cut and deburr strips of scrap .060" styrene, as was done for the original cabin. Keep in mind when installing the strips that the ceiling will be inset below the eave line and the floor will be inset from the bottom up to the top of the concrete line. The corner blocks do not have to reach all the way to the floor and ceiling, in fact, this is one of the jobs where you can cut by eye without any fancy measuring. To position the corner blocks, you could draw lines 1/16" in from the edges and position the glue blocks up to them, but it is usually easier to use a strip of scrap .060" styrene as a spacer to position the block while the solvent evaporates. Use the strip on edge, keeping one face flush with the edge of the wall and keeping the corner block tight up against the other face of the strip. For long blocks, there is no necessity to glue the full length at once. One of the joys of solvent welding styrene is that you can work along the joint a bit at a time, adding a bit more solvent with the brush each time you move along. For a really good job, you should use corner blocks not only where the walls come together but also where the ceiling and floor meet the walls. There are two ways of installing the blocks, the good way and the not so good way. The good way is to install them all before you put the walls, floor and ceiling together. The not so good way can spoil your weekend. Note in the diagram above that the side walls are set in. This means that each end wall will need four corner blocks while each side wall will need only two. On each end wall of the original cabin one block about 5-1/2" long was installed 1/16" below the eave line, and another similar block was installed 5/8" up from the bottom. Then two blocks about 3" long were installed, one set in 1/16" from either side. On each side wall, two blocks about 7-1/2" long were installed, one 5/8" up from the bottom, one 1/16" down from the top. One last thing before assembling the basic box - if you think you might ever need a hole through the floor, now is the time to cut it. The author routinely cuts out the center of his floors to allow easy installation of lights, etc., but other modellers leave them solid to help keep bugs and dirt out. The center 4" x 6" of the original cabin's floor was cut out, leaving a rim 1" wide to reinforce the bottom of the cabin and keep it square. Finally it is time to glue up the basic box. This is best done on a flat surface, preferably one that will not be ruined by stray solvent - no painted or varnished surfaces. Your antique dining room table is definitely out. With corner blocks installed, it is an easy matter to set one side wall into the corner formed by the end wall and the corner block and run a good swash of solvent down the seam with the brush. Do not skimp on the solvent - you want enough to penetrate the joint and glue the side walls to both the end walls and the corner blocks. If you feel like you do not have enough hands for this job, try taping all four walls together with bits of masking tape, then running the solvent into the joints. When the joint has had a minute or two to set up, and before removing the tape if you used it, gently insert the ceiling and apply solvent to the joints. For the ceiling, quickly applying some bits of tape after applying the solvent often helps. Allow a few minutes more for the ceiling joints to set up, then flip the basic box over and install the floor in a similar manner. Again masking tape can be helpful but do not pull it too tight or it may bow the bottom of the building inwards. Place the building upright again and set on a flat surface to allow the joints to set up completely while you work on the roof. Remember those triangles you cut off the corners of the gables way back
several pages ago? Now is the time to find them again, along with the roof
pieces. For the cabin, you will need two of the scrap triangles. For a
larger building, you will probably need more. You might just check your
triangles against the tops of your gables to make sure the angles are the
same (if your roof slope is anything but 45 degrees, they will not be.)
Once you find they match the gables, or you make them match, you can cut
a bit (1/2" or so) off the top corner. This is to clear the corner block
that you should now install on the wider roof pieces. The corner block
on the original cabin roof was about 7-1/2" long and was installed 1/16"
in from the edge. Once you have attached the corner block and cemented
the two roof halves together, you can install the two roof braces (triangles)
about 1/3 of the way in from each end. This is one job where tube glue
works well, and it does not matter if it gets smeared around. Just run
a bead of glue down the two short edges of the triangles and set them in
place. Put the roof aside while the glue sets. Put one side of the roof
on the table with the other side sticking straight up - this will take
the stress off the joints while the glue dries. Let the glue dry for five
to ten minutes (tube glue is slow - it is usually faster to install corner
blocks with solvent if you are in a hurry.) After that time, gently try
the roof on the rest of the building just to be sure it fits, then set
it aside for more drying while you put siding on the walls. After the walls
are sided, attach the roof - then the building will serve as a convenient
holder while you attach the shingles.
Now we are on the home stretch. The hard work is done. All that remains is applying the shingles to the roof and the siding to the walls. At first this stage may be a bit time consuming. But after a bit of practice, the shingles and siding seem to fly into place. For details on making and applying the shingles and siding, jump to the article Large Scale Shingles and Siding. Once all the shingles and siding are in place, your building is complete, and ready to paint. Apply your favourite paint or visit the page on Painting Outdoor Structures. One last thing before you add your newest building to your railroad. How about dropping us a line, and letting us know how you made out? We would appreciate your comments, good or bad, on our attempts to explain exactly how we make our buildings so that we can do better next time. |
