Curved bench work is easier than it appears, honest!
Before I get started, I'd like to clear up a couple of misconceptions about curving the bench work.
You do not need to steam the wood
You do not soak the wood in vinegar for several days!
In fact you do not need any fancy or expensive tools. More than likely, if you own any woodworking power tools you'll have the tools you'll need.
You'll need a circular saw or table saw, electric power drill with a screwdriver bit, "C" clamps, a belt sander or orbital sander or sanding block, glue, and a little time. If you have a radial arm saw or table saw, the repetitive cuts will be a little simpler. Better yet if you know a finish carpenter or cabinet maker you'll have this project in the bag!
The main framework can be constructed from 1 x 4 lumber of 1/2" to 3/4" plywood as mentioned before. The curved section of the framework is made from multiple layers of 1/8" masonite (hardboard) which are cut to fit the area and glued and clamped to the existing framework. Each layer has to be glued and clamped individually and left to dry thoroughly before adding another layer of masonite. After all the layers of masonite have been glued in place, several screws can be driven and countersunk for added protection.
Lets start with the basic balloon module. Figure "A" shows a balloon that has all 90 and 45 degree corners.
Figure "B" shows the same balloon with two corners made with rounded framework.
Figure "C" shows how the basic frame is made from 90 and 45 degree joints and nothing more than three rectangular frameworks attached to one another with two spandrels and two 45 degree fill pieces.
Figure "D" has the layers of masonite added to round off the corners.
Figure "E" shows a detailed view of the main framework and how the masonite is attached. You will need to add a piece of 1/2" wood to the outside of the framework (called a scab) to match the thickness of the layers of masonite (4 layers). Most of the Bend Track modules that our group uses are made from good interior grade plywood for the main framework, so four layers of 1/8" masonite will equal the thickness of the 1/2" plywood.
You will need to rough cut the pieces of masonite a little longer than needed and then cut and fit them until they fit the radius that you desire. Once the first piece fits you will need to glue and clamp it until it dries. (NOTE: Use the YELLOW Carpenter's glue, it dries a little faster and is a LOT stronger than Elmer's white glue).
After the first layer of masonite has dried THOROUGHLY, apply a second layer over the first one, applying a generous amount of glue so that you cover the entire surface of the first piece. Then apply the "C" clamps along the entire curve. Wipe off any excess amount of glue that drips out with a ran dampened with warm water. The more glue you wipe off now means the less you may have to try and sand off later, which will save your sanding belts.
Now just repeat the previous process until you match the thickness of the plywood scab. After the final piece has been applies, you may wish to run a couple of screws through the layers of masonite and into the framework. Now use a wood putty such as ROCK HARD and fill any holes or uneven joints and sand smooth.
With this simple procedure you can build all kinds of curved bench work and make all kinds of interestingly shaped modules, even to the point of having NO straight portions of framework ANYWHERE AT ALL on the module outline! (except of course for the ends to clamp to the next module).
Figure "E" shows how to make two types of curved bench work. The top picture shows how to put in a 90 degree turn while the bottom shows an offset in a "straight" section.
Follow the same steps as above and you should end up with the same results. Then just let your imagination run wild and have fun.