For newcomers to scratch-building, it may seem a difficult task to make all the round shapes and parts on a spaceship. In the early days, I remember feeling powerless and inadequately skilled by the thought of actually having to make large round or multi-curved parts from plastic materials. Over the years I have learned how to accomplish this in relatively easy and cheap ways and without the need of expensive machines or equipment. I primarily use two basic approaches in my modeling: Laminating and Ribs & Putty.
Laminating is the building of layers to form a desired shape. The first thing you need to do before laminating is draw the outline of the object you want to build. For example, if you want to laminate strips of 1mm sheet styrene, you should draw vertical or horizontal lines with 1mm intervals until you have filled the outline of the object.
To make the parts you see in the images below, I had to go through several repeated steps. The first step was to cut the strips of styrene I needed. Based on my drawing, I cut each strip to a specific width. I started laminating the strips from the center out. I put a pre-cut styrene circle in the middle. The middle area had to be open, but I needed a core from which I could start laminating the styrene strips.
The styrene circle was removed as soon as I had laminated all the strips. The shape was raw and crude, but I worked it by scraping it down with the blade of an Olfa-cutter. Please use a protective glove on the hand holding the part. You could cut off a finger (or two).
I scraped off most of the excess material this way to get the shape right. The next step was to fill the gaps with putty. To fill the larger gaps I used two component non-shrinking polyester putty from Plastic Padding. I sanded it down and filled the small remaining gaps with Tamyia putty. I sanded it a second time with fine grain paper until the finish was perfect and primed the parts with Tamyia primer. The primer allowed me to see any last flaws in the surface.
These were carefully filled and sanded before I applied a new and final coat of primer. Satisfied with the results, I could now prepare to duplicate the parts by casting them in silicon molds.
In the images below, you will also see another example of laminating, this time directly on the model. When I built my TIE Bomber, I laminated the socket for the wings onto the PVC rod. It became a solid construction!
Be sure to use styrene glue when laminating styrene. I use both thick and thin glue. Smear the strip with thick glue and laminate it to the construction. Then let a few drops of the thin glue run along the joint. It is also a good idea to have a few small clamps on stand-by to hold the strips in position until dry.
Ribs and Putty
Another way to make multi-curved parts is to construct the shape with ribs and filling them with plastic scrap and epoxy putty. Epoxy putty is heat resistant. This method is great for making plugs for vacuum-forming. I used this method on my Imperial Probe Droid model. Both the head and upper body of that model were constructed this way as you can see in the images below.
These parts were to be detailed with vacuum-formed styrene sheets. To make the forms I cut dozens of identical ribs and glued them to a styrene ring. I filled the space between the ribs with slices of styrene sheet and a coat of epoxy putty. The putty was then sanded, filled and sanded until the finish was satisfying. Here are the finished parts laid out before detailing.