Scratch-building F1 Cars
by Jaime Brocal Cabanes

Part I - Planning, Layout, and Forming the Body

The first thing you need to have when reproducing a car from scratch is the desire to build it! This may seem obvious, but I can tell you it's very important to have a strong will to make a particular car. That way you will gladly put in all the effort needed to obtain the best results.

The most easy cars, when working with plastic sheet (the technique I'll describe here), are those with a lot of straight lines. The more square and parallel the shapes are, the easier the building becomes.
Here's a list of easy cars:
 
Ferrari F310B, Benetton B195, Williams FW16, ´97 Arrows, McLaren MP4/8, and in general almost every ground-effect car, since they had square and simple sidepods.

After choosing your desired car, then you have to find as many reference photos as possible. A very useful shot is one taken from the side and with zoom (this is used to produce a true-to-scale image).

Then you have to take measurements. A very important figure is the wheelbase, because this gives a general impression of the size of the car. You can find this figure in most of the specialized GP magazines and pre-season previews. With this data, you can determine the scale of your reference photos. Here are some typical dimensions for F1 cars:
 

Specification	Dimensions
Wheelbase	70´s:      265 cm  80-82    270-280 cm  83-88    285 cm
Rear overhang	up to 1982:  80 cm    83-90:       60 cm    91-97:       50 cm
Rear wing width	up to 1982:    110 cm   from 1983:    100 cm
Maximum rear wing  height	up to 1982:    90 cm  1983 - 1986: 100 cm     from 1997:   80 cm
Body width	140 cm
Front wing width	up to 1992: 150 cm   from 1993: 140 cm
Whole car width	up to 1992: 215 cm   from 1993: 200 cm

 

After you have decided what are the correct measurements, you should make scale drawings, so you won't have to be always measuring the photos and with the calculator. But remember to always keep your photos on hand.

Now you have to decide what kind of parts you need. We are using 1mm or 2mm thick plastic sheets. It's good because it permits you to build up volume while making round edges. I buy it in a factory that makes plastic for the plastic cup makers. It's much cheaper than in hobby stores (1m x1.5m for 10 dollars or so).

The most usual layout is: side pannels, upper cover that includes sidepods upper surface, undersurface, nose side pannels, nose up and down surfaces (if nose is very rounded, you can use two or more sheets so you can, afterwards, sand it and round it). The drawing below shows roughly how the Ferrari F310 chassis is laid out using this technique.
 

The engine cover/air intake can be made with a technique similar to that of the nose, but you can also simply model it with some putty. Since it's usually not very big, its easy. But be careful to preserve the symmetry! Once you have the parts made, you can bond them together. Be careful when working with inclined surfaces to always at your photos, just to make sure that the visual impression is similar to what you see in the photos.
 
There are some effects that cannot be reflected in drawings or measurements, so you must have good eye. While the glue sets, you must make sure you are respecting the parallelism and symmetry of the real thing, because you won't be able to make corrections later! If the body sets bent, bent it will remain forever. Once the body is perfectly set, you can begin using putty (my favorite is two-part epoxy) to add roundness, fill unions between panels, or make any detail that couldn't be done with plastic.
 

Part II - Finishing the Body and Adding Details

Take care with the two-compound putty. When you have just mixed it, it is very, very sticky. that means that it is good to fill holes and that it bonds very well to difficult contours, but it is very difficult to mold with fingers (they must be always wet!). So you should wait half an hour or so to begin to give shape with your fingers.

While setting, putty becomes stiffer and stiffer and less and less sticky. This is the moment to make up forms. A good tip is to use plastiline as a base. You can put on it a thin sheet of putty, and then give shape. Plastiline will keep the forms, so when putty is very very set, you take off the plastiline obtaining a fine part with the form desired.

In an hour or some more, the putty gets a consistance similar to hard rubber, and that s the ideal moment to cut it with a sharp modeling knife. In 4 or more hours, it hardens almost completely, but generally you have to wait almost a whole day to begin sanding. When it is hard rock, it is very rigid and thus very fragile, take care.

Well, now we have the body with the putty. We have to cut, drill, and sand to obtain the convex roundness we want. Sometimes you will have to repeat the putty process in some areas. Well, this is very important: ALWAYS LOOK AT THE PHOTOS WHEN ROUNDING SHARP EDGES. If you take off too much material, it is not easy to put it back again. You have to see the photo and try to obtain the same shapes, not giving shape and then checking.

Don't be ever too confident in your memory. I remember I rounded too much the upper edges of the FW14 sidepods, just to see then that they were almost square!! I had to build up again with putty. Not much difficult, but monkey business if you consider I had the sharp edges and it would have been enough with a light sanding!

Now you have to mark the lines of the union between panels. Don't make them too wide. You can use a cutter in the beginning and be more confident when the mark is deeper. A needle is a good tool.

Well, once you have a perfect body (like Elle McPherson´s, for instance :-) you can prime it to see the defects and correct them.Well, that's it for the body. To make wings, I use thin plastic sheet. I bend it and bond it. You can obtain different profiles. If the wing is not straight (like front wings) you can use 1 mm sheet and sand the edges. You can bend the sheet by heating it. If you simply bend it in cold, it won't keep the shape.

To make endplates, use thin sheet. If the rear edge, as is common, has steps, use two or more superimposed sheets. To make wishbones, I used to use plastic bars, pulled with heat. Nowadays, wishbones have special wing profiles, that are more easily made with thick sheet.

To make uprights you can use thick sheet and putty, the forms are quite simple and they usually are hidden.

(Thanks Jaime, for sharing your great ideas and expertise! -KJS)