As a kid growing up in the 70’s & 80’s, I was obsessed with movie special effects and consumed whatever information I could find, reading and re-reading movie magazines until they literally fell apart. At some point I caught a TV special about the making of Empire Strikes Back that showed some footage of the ILM model shop. It briefly showed a spaceship model being made from scratch and my young mind was blown.
More than 30 years later I finally decided to try my hand at building a model from scratch. I have taken a somewhat hybrid approach, using a variety of techniques: styrene scratchbuilding, kit-bashing, vacuum forming, machining, and 3D printing. I will describe these techniques individually and show how these been used historically and how I’m using them in my project. This will not be so much a step-by-step guide as a general overview using my model as an example. I hope that you find this interesting and might even be inspired to try some of these techniques yourself
Step 1: Basic Tools, Materials & Techniques
The material that I will be working with is Hi-Impact Polystyrene (HIPS) (here after called ‘styrene’). It is the standard material for injection molded model kits. It is available in smooth and textured sheets of various thicknesses and as rods, tubes, domes, and strips at your local hobby shop, from Evergreen & Plastruct. From here out, I will refer to these styrene shapes simply as 'Evergreen'.
Sheet styrene is MUCH cheaper when purchase in large sheets from a local plastic supplier than buying it from a hobby shop in small pieces. I got mine online from McMaster-Carr. A 12" x 24" piece of .030" thick was about $2.40. You might do even better buying a full 4' x 8' sheet from a local supplier.
Styrene is easy to fabricate using only hand tools and can be painted to represent a variety of materials.
Gluing is generally done with a solvent which works by dissolving the plastic locally and fusing the pieces together. I prefer Tamiya brand cement which comes in both standard (orange label) and Extra Thin (green label). They both have a built in brush in the cap and are quite easy to work with. The standard orange label one is thicker and has more working time to align your parts. The Extra thin is my favorite. Just line your parts up and run the brush along the joint. Capillary action wicks the solvent into the groove and the parts are joined. Easy. Avoid old-fashioned Testors cement in the tube. Strictly for squares.
For tools, a ruler and and a hobby knife will get you 90% of the way there. Another great tool to have is a plastic scriber. Olfa and Tamiya both make great ones. They excel at making straight cuts. A few passes across the plastic (using a metal ruler to guide the cut) is all that's needed. Then just bend the plastic along the scribe and it will break cleanly along the score. This is much faster than cutting all the way through.
Small holes can be drilled or made with punches. For cutting larger holes in sheet styrene, I've had good luck using an Olfa circle cutter. Again, it is not necessary to cut all the way through, as the plastic will separate along the score with a little flexing.
A handy tool for cutting Evergreen is something called the Chopper. It's essentially a single edged razor blade attached to a pivoting arm, like a paper cutter. There is an adjustable stop which is invaluable making multiple cuts of the same length. Of course, me being a cheapskate, I made my own.
For sanding, I make my own sanding sticks by bonding sandpaper with double-sided tape to paint stirrers and Popsicle sticks. Wooden coffee stirrers can be used if you need to get into really tight spaces. 220 and 340 grit paper are good general use and are usually as coarse as I need to go, with styrene being quite soft. 400 and 600 wet and dry grits are handy to remove scratches.
A helpful jig that I made to glue sides square is simply two pieces of scrap wood glued 90˚ to each other. I then faced each piece with sheet steel, so I could hold pieces in place with magnets while the glue dries. Care must be taken not to let the glue wick between the plastic and steel as this will melt the plastic to the steel and mar the finish.
3D printer filament is also available in styrene (known as HIPS). It has similar printing properties to ABS. I’ve found that it sands beautifully and glues readily with the Tamiya cements. While you can’t print with the kind of detail you need for scale models, it excels for printing larger shapes that you couldn’t make in other ways. These printed parts can then have further detail added through the addition of model parts or Evergreen shapes.
Step 2: Subject Matter and Beginnings
The choice of subject of course comes down to personal taste. I wasn’t interested in recreating a screen accurate model of a movie subject due the tons of reference material needed. On the other hand, I didn’t feel I was ready to go completely freestyle, grab some plastic and just start improvising.
What ended up working for me was to find a rough concept sketch that I found interesting and use my imagination to interpret the lines on the page. The sketch I chose was from the blog of artist Rob Turpin, It’s a very unusual design that I was immediately drawn to. It has a quality that reminds me of the work of Mœbius (Jean Giraud). Plus, it looked really difficult to make. I likes a challenge, me!
When making something as complex as this, it's easy to become overwhelmed. I found it helpful to approach it as being an assemblage of simpler shapes and to consider each one separately. Each one becomes a puzzle that needs solving as you plan your approach. I decided to start at the left and work right, like reading a book, tackling each part separately.
I knew the bubble shaped canopy would probably be limited to a found object, rather than something I could make, and because of this, this part would drive the size of the entire model.
I found that acrylic test tubes were available cheaply in a variety of sizes. I chose a 40mm test tube and the whole model was scaled to fit this one part, making the finished model a total 12 inches long (300mm). This worked out to be around 1:87 or HO scale.
I imported a jpeg of Rob’s sketch into a CAD program and scaled it until the canopy was the size of my plastic test tube. This gave me a reference that I could draw on top, design parts, and take dimensions from. This CAD file was the backbone of the whole project. I also printed out the sketch full size so I had a paper guide that was 1:1 with the physical model. This was handy to have on my bench as I worked.
The clear plastic of the test tube was quite brittle and prone to cracking (like a clear CD case). I made a simple fixture out of a piece of scrap plastic that clamped on the tube and gave me a surface to guide a fine hobby saw against. The tube had an artifact from manufacturing at the very end that was both inside and out. I tried with partial success to polish this out.
The ribbed section that surrounds the bubble was turned on a lathe from a 2” piece of solid styrene rod that I bought from McMaster-Carr. I also made a fluted styrene ring added to the bottom to add more detail. These were glued together and a section was cut out to fit a piece from an airplane kit. The inside was sanded to match the contour of the test tube and the gap was sculpted in with Aves epoxy putty.
Step 3: Vacuum Forming
The next section to consider was the hull. I decided to make the front portion as one vacuum formed piece, because of the large radiused corners.
Vacuum forming is a manufacturing process where by a thin sheet plastic is held in a frame and heated until soft and then stretched over a positive form. The plastic is pulled tightly around the form using vacuum and allowed to cool until hard again.
Styrene is an excellent candidate for vacuum forming. It can be softened at a relatively low temp (385F) and holds detail well. Vacuum forming is an easy way to make parts that would be very difficult to make in other ways. The resulting parts are light weight and relatively strong.
The vacuum former that I used is homemade, but great results are possible using a home oven and shop vac. For example…
I fashioned the positive form for the hull out of a high density foam using a band saw and a belt sander. I tapered the sides about 5˚ to aid removal from the plastic. The form was sprayed with primer and wet sanded with 600 grit sand paper to get a nice smooth finish. Having any surface texture will make it harder to separate the plastic from the form later.
The finished form was placed on the vacuum stage and dusted with baby powder to help keep the plastic from sticking. I loaded some .060” thick styrene into the frame and heated it until it drooped about the same amount as the form was high. At that point the frame was brought down, stretching the plastic over the form. Then the vacuum was turned on, causing the plastic to suck tightly around the form. Once cool, the plastic was removed from the form and trimmed into shape. Remember that the final part will be thinner than the starting material thickness because you are stretching it over the form. In my case, the finished hull was less than half the starting thickness.
Step 4: Building the Rear Hull
Next a box was built out of sheet styrene to fill in the rear of the hull. The sides were cut from .030” sheet using the scribe and score technique. The plastic scriber is guided along a metal ruler a few passes which scores a line in the plastic. The plastic is then bent along the scribed line which snaps cleanly. A few passes with sand paper and it’s ready to go. It’s often easier to cut a side a little big, glue it in place and then sand the overlapped edge flush.
Some styrene sheet was glued into the inside the vac form to further strengthen things. I also glued some Evergreen strips to register the styrene box when it's inserted in the vac-formed hull. Some textured sheet (also Evergreen) was added to the box along the sides and bottom to add some interest.
The convoluted middle section was turned on the lathe from the same 2" rod that I used earlier. This had a 1/2" hole drilled to receive the armature rod.
I then began to add some styrene shapes that would form the support structure of all the engine details. These were a combination of sheet construction and machined shapes. I decided things would be more interesting if I varied the surface a bit more, so I made two square cutouts on the back of the box. Into these I fit two small styrene boxes and sanded them flush. 1/8" Evergreen rods were bent using a heat gun to form pipes. These were routed into the two square cutouts.
An important thing to consider from the beginning is having some kind of an armature or support structure in your model to hang parts on and as means of supporting the model for display (or filming). Most movie models have a number of places where some detail can be removed and a rod can be inserted to support the model during photography. In my case I decided to use a 1/2 inch aluminum rod down the centerline of the model. This would help keep all the circular parts concentric when I glued them together. It was also very helpful as a way to support the parts during construction and later when painting.
Step 5: Kit-Bashing
To detail the rear engine portion of the hull I turned to a technique called kit-bashing.
Kit-bashing is the process of using commercial model kit parts to add detail to a model. This is usually done in a way that obscures the origins of the original part. Bits of military armor and aircraft kits are arranged in a manor to give the impression of functional mechanical detail and to catch the light as the model moves across the screen, creating moving shadows across the surface which increases visual interest. This technique has been used since the early 60’s on the Gerry Anderson TV shows like Thunderbirds, but probably reached its zenith with the original Star Wars trilogy.
Military armor kits were often used, but so were racing cars, airplanes and ships. By choosing kits of different scales, a variety of detail levels can be achieved. The model makers at ILM called these surface details ‘greeblies’ or ‘greebles’ .
Accruing a good selection of model kits to raid for parts can be difficult because kits are expensive and you often don’t know what you’re getting for parts until you get it home. One thing that can help is a number of websites have photos of the parts ‘trees’ so you can peruse the kit before you buy it.
Once you have some kits, it’s important to stop thinking of them as kits. They are now raw materials. I often take them out their boxes and collect them in totes. I also store parts that have been separated from their trees into bins that are easy to sort through when detailing, grouping like parts together.
If you carefully study the screen-used sci fi models from the 70’s & 80’s, you notice that these kit parts often do not evenly cover the entire surface of a model, but tend to be clustered together in groups. Often, they are filling trenches or recessed areas. Locally, things are arranged so that they seem to connect and have some sort of function, even if somewhat abstractly. Groups of parts can be connected with ducts or piping made from Evergreen bits.
After adding some kit detail to the engine area, I also added some further detail to the front vacuum form. I cut a rectangular hole on either side and built a shallow plastic tray under each. This tray was also filled with an arrangement of parts, because I thought this would look better than simply sticking them on top. I also cut some panels from .030 sheet and glued them in place. Among these, I fit some hatches and armor plates from a couple of 1:72 scale tank kits, figuring the scale was close enough.
At this point things look a bit disjointed because of the different colors of the kit parts. Once a coat of primer is applied this desperate collection of parts will suddenly become cohesive.
Step 6: 3D Printing
I had no idea how I was going to make the bulbous rear section. After reading that styrene printer filament was available, I decided to try printing the parts. I bought a cheapo (sub-$200) printer kit, the Tevo Tarantula. Once it arrived, I made some improvements based on shortcomings I had read about while researching the printer. Most of the improvements consisted of stiffening the frame and replacing the laser cut acrylic parts with machined aluminum ones. I also upgraded the hot end due to the higher temperatures needed for HIPS. I built a simple enclosure out of pink foam insulation to help keep the print from cooling too quickly and warping.
The rear segment was modeled in four pieces and featured a centrally located 1/2" hole that would allow for the aluminum armature rod to run through them and to help with alignment when gluing them together. The parts printed quite nicely. Any layer lines were sanded off and voids were filled with auto body putty. The printed styrene parts were strong and very light weight. The styrene filament sands so much nicer than PLA and bonded readily with the Tamiya cement.
Next, I printed some thin styrene rings and glued them around each recess in the rear section. Then using some Aves epoxy putty, I blended in the inner transition between the ring and the recess.
Step 7: Miscellaneous Details
The large rudder-like things were next. These would have been easy to cut from sheet stock, but I wanted them to have a tapered cross-section, so I chose to print them. They wouldn't fit on the print bed, so they were printed in two pieces each, using some Evergreen rod as locating pins to align the two halves. A bit of auto body filler hid the seam. They were then detailed with Evergreen bits.
I thought it would be cool to be able to see a pilot and some cockpit detail though the bubble. I imagined the pilots seat and controls to be an open framework that used gyros to stay level while maneuvering. With this in mind, I built up a structure out of 1:72 tank parts and a bit of Evergreen. The frame was glued to a small piece of Evergreen tube that I mounted on a thin styrene disc. I founds some HO scale astronauts online that included a couple seated figures. One was chosen and fixed to the seat with some superglue.
The two antenna-like stalks on either side of the hull were made from kit parts and some Evergreen rod and tubes. The paddle shaped pieces at the end were cut from a couple of 1:35 scale helicopter blades. To give the impression that these were adjustable, I added some greeblies to suggest a some sort of mechanical controller. This was made in the usual way from kit parts and Evergreen and glued in between, along the top of the rear hull.
The rear of the ship in the drawing has the suggestion of some mechanical detail and some small fins. I built this from a selection of model kit parts. The fins were 1:72 helicopter blades. This assembly was built on a thin plastic disc, which would all me to paint it separately.
The small tank-like object on the top rear of the ship was turned on the lathe from a solid styrene rod. A short length of 1/4 styrene tube was attached to allow for easy gluing and registration.
Step 8: Painting and Weathering
Now all that was really left to do is painting and weathering. At this point the model was still largely unassembled, with the model broken into its major sub-assemblies for easy handling during painting.
My wife is quite sensitive to solvent vapors, so I chose to use water based acrylic paints to finish the model. Vallejo brand acrylics are well thought of and available at my local hobby shop, so I decided to go with those. The plan was to lay down the base color in acrylic using an airbrush and then use oil paints over this to age the model.
I bought a "For Sale" sign at the hardware store and cut it into 3x5 inch cards. Plastic signs are printed on...you guessed it, styrene. These cards were handy to have near by when I was painting, so I could check how the airbrush was spraying anytime I mixed new paint or varied the pressure. I could have used paper, but the paint would soak in a bit. The plastic sign was cheap and a perfect stand in.
Vallejo paints come in small dropper bottles. To make it easier to mix the paint, I added a stainless steel #10 nut to each bottle. Then I modified a small clamp to fit in my jigsaw. The bottom jaw of the clamp was built up with Aves epoxy putty, and used to take an impression of the paint bottle bottom. The top of the clamp was drilled out to receive the top of the bottle cap. Now the jigsaw could be used as an electric paint shaker.
The two colors for the base coat were orange and grey. I found a nice grey that I liked right out of the bottle, but no so for the orange. I would up mixing one from a couple different colors. Areas where the colors touched were carefully masked with tape. Once the model was base coated, I let it dry for a couple of days to let the paint fully cure. At point the paint job gave the model a very toy-like appearance. That's where weathering comes in.
Weathering is the process of simulating the effect of age and the elements on the surface of your model. Things like rust, chipped and faded paint, and dust and grime can all be applied though some fairly simple techniques. For my purposes I'll be using artists oil paints. Oils are quite useful because they can be applied in very transparent layers (so effects can range from quite subtle to heavy handed.). For these I chose some inexpensive student grade paints and an odorless turpentine for thinning. A piece of corrugated cardboard makes a great palette, because it absorbs the linseed oil in the paint. With less linseed oil, the paint dries more quickly and with a matte finish.
To break up the monotone orange finish, I applied small dots of red, yellow, white and brown oils and blended them in with a touch of thinner. The effect is subtle, but it really helps to add some color variation. Brown paints were mixed and brushed into the places where grime would collect. Excess paint can be wiped away, leaving it only in the recesses. Because oils are slow to dry, the technique is very forgiving because its possible to go back if you take it too far.
Once all the parts were weathered, I did the final assembly and attached it to the base.
All that's left to do is some painting touch up and a final weathering pass to help integrate the parts together. I will let things dry a couple of weeks first, so I do not disturb the previous weathering.
Thanks so much for following along. I hope I've inspired someone to try this for themselves. In these days of CGI, we have to keep these techniques alive!
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