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e-mail me at: trike@zoomshare.com
Old
Building A Prototype Body
When I started, I hade no idea how I was going to build this shape that was so easy to draw on the computer. Nobody I knew had any experience to help point me in the right direction. All the better; it forced me to come up with my own plan. During my research I saw people use several plywood ribs that represented their car's shape. Although, there was so much empty space between the ribs. It seemed like a large source of inaccuracy. I decided on slicing the CAD shape into many slices, from front to back; like a loaf of bread. Each slice could be printed out on a plotter at a 1 to 1 scale. Then these printouts could be traced onto cardboard. A sandable foam would fill the gaps. As difficult and tedious as it was, building this car body was a great leaning experience. It demonstrated to myself that I could build any thing I could draw, and that I could draw anything that I could imagine.
After many weeks of cad work one summer, I drove out to Suny Delhi college to make the contour line printouts. I numbered each line and fit 8-15 lines on a sheet. Next, I needed lots of cardboard. Just down the road, a furniture store had plenty of large boxes. They were happy to let me take all of this "junk" off their hands for them; always watching with curiosity as I walked out with nearly 200 large sheets. First, a table was needed to lay out the cardboard ribs. A steel frame, covered with 1" thick plywood, filled the back of the garage. The table extended 3 inches beyond the foot print of the car body. Within this foot print, rib placement lines are drawn perpendicular to a center line. The rib lines are drawn 2 3/16" apart. (2"for the polystyrene foam and 3/16" for the cardboard thickness. The polystyrene foam can easily be purchased from home depot in 2' x 8' sheets for around $12. When the ribs were drawn, care is needed to take into account the thickness of the rib material, otherwise the error will stack up with each successive rib.
The ribs were bonded to the table with wood glue. Then foam was snuggly inserted and was also secured with wood glue. Foam spacers held each rib apart while pressure was applied on the last rib to hold the spacers in place. A framing square is used to ensure that each rib stands vertically on the table. 
I used a long razor blade to slice off the excess foam, careful not to cut deeper than the cardboard ribs.
Next I started sanding the foam down to the cardboard ribs. I used a sure-form file to create the smooth curved surface. The file resembles a cheese grater with a handle. It was quite exciting to see this imaginary shape come to life. All this work was done in the middle of the winter in a garage without doors. So not only was I cold, the wood glue needed a kerosene heater under a tarp to maintain 50 degrees. And I couldn’t get much done at all when the temperature dropped below 25 degrees.
Once the foam was fully sanded, it was time to cover the plug with a sandable material. There are many different materials to choose from. “If I only knew then what I know now!” Sometimes people use plaster. Plaster is very heavy and hard which makes it difficult to sand. Body filler, commonly known as Bondo has its problems too. You can clog your sandpaper quickly. I made the decision, and the mistake to use drywall compound. It has the consistency of soft chalk. It sands easily and allowed me to smooth out the rough spots in a matter of days. Unfortunately drywall compound is very brittle and is not a permanent solution for a car body plug. Later this surface was strengthened with an oil-based paint. The paint soaked into the porous surface and created a smooth hard finish. The material mistakes I made here forced me to produce a female glass mold of the car’s shape and then a male glass mold out of the female. All that work, just to get back to a positive shape, made of a permanent material.
If I could go back in time and give myself some good advice I would say to cover the foam with epoxy mixed with a lightweight filler called micro-balloons. Micro-balloons are very tiny hollow glass spheres. Basically they take up space to create material that is cost-effective, strong, and sandable. Next, I would paint on with a roller, a polyester primer. This primer is the key to obtaining a strong permanent surface that is easy to sand. It costs $65 per gallon but it’s worth every penny. UScomposites sells the best products I’ve used, at very affordable prices.
You can find Duratec Gray Surfacing Primer at: http://www.uscomposites.com/polyprod.html (1-561-588-1001)
This small shape is actually the first part I created for my car project. It is hard to visualize, but it will actually become the dashboard and armrests. Mentally turn over this shape and visualize a driver sitting inside. The part I am touching will become the dashboard, and the top of the shape is where the driver will sit.
This is where I learned how difficult it can be to work with Bondo. After constantly changing clogged sandpaper, I decided to never lay down this much Bondo again. Later I would apply fiberglass and polyester resin over the shape. The glass shell would be removed and then incorporated into the larger fiberglass mold.
The yellow object you see here is the female fiberglass mold that was pulled off of the large car body plug. After applying three layers of mold release wax and one layer of sprayed on PVA film, I was ready to start building a male mold. These male molds were created in sections. The entire body would be made of a front, rear, center left, and center right section. In the picture below you can see a dividing board running up the center of the car body. This center board prevents resin or fiberglass from attaching to the other side of the mold. Here you can see polyester resin being slowly painted over three layers of wax and PVA film. The fiberglass pieces are laid over top and then saturated by either a paint brush or a paint roller. I am using a heavy, 24oz, plain weave, fiberglass cloth. I have many other types of cloth but this is by far the strongest. (Only $1 per pound shipped from eBay.) Normally you would lay down a layer of glass mat first, to prevent a woven pattern from bleeding through. As polyester resin cures, it shrinks, so the outermost layer should be glass mat, not woven cloth. In this case there is still many months of sanding left, so I was not worried about bleed through. After applying 4-6 layers of fiberglass cloth, the mold was left to cure for 24 hours. Next, a wooden framework was secured to strengthen the mold. Without this framework, the fiberglass could bend or twist from its desired shape.
Here we see both left and right fiberglass sections finished. A slot was cut on the bottom so that the driver’s compartment could be inserted.
Pictured below, the female mold with its left and right male molds still attached are turned back over on the floor. This is the best part of mold making. Wedges are hammered in between the male and female molds to separate them. Once separated, the male molds will fall a few inches away from the female mold.
This is what the middle section looks like once it falls away from the female mold. This section is in two pieces; left and right join seamlessly.
The bodywork in front of the driver was made in a curved mold with a constant radius. I needed a way to trim the curved sheet of fiberglass symmetrically on a horizontal plane. I placed the fiberglass panel in a swimming pool and traced the water line with a permanent marker.
Here is a look at the female and male molds of the front section
Since this picture was taken, the entire body was sprayed with a thick layer of Gray surfacing primer, and sanded to a smooth finish. To this day, it sits patiently, waiting for a purpose. If nothing else it was a great learning experience. In the future I hope to have the funds and facilities to breathe life under this shape.
still under
construction
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