Aug 20

Building F1 resin model kits: A step by step guide for novices – Part 2

By Mario Covalski – Editor ( Online magazine supported by HobbyLink Japan)

Step 4: Detailing the body

Once all the flaws have been corrected and the mould lines removed, I started by detailing the body, addition of parts and necessary drillingsto go on with the construction, these tasks may include some modifications to the kit, as we’ll see later, this depends on the level of accuracy you want to get.

Probably, it will be necessary to do some drillings to the body, for the suspensions, antennas…etc. Don’t use as guide the marks the manufacturer provides, analyze the parts and the references until deciding where you should do them. Start by using small drills, so as to be able to correct a possible error, and not to “splinter” the hole edges.

Once the hole was marked with 1 mm drill, the definitive of 1,5 mm was drilled, not very deep, in this case just to house a PE part. A pin vise will be proper. Don’t use a Dremel.

The picture shows how a drilling at 45° is being made, the secret is to drill a very small hole first to enlarge it later, this will not be troublesome. Be careful and do it slowly, to avoid breakages in the resin.

Monocoque look with the drillings for the suspension arms and the PE(s), that represent the nose fasteners. Note that each hole has a different depth.

The nose with the holes already drilled.

Sometimes, you can make a mistake by using a larger diameter drill. Just regular or polyester putty will work to mend those errors: fill the hole, sand it, up to getting a flat surface and, make the new smaller holes very carefully. Have a look at the red circles, there you’ll still appreciate polyester putty remains, and how the mistake was solved.

It may occur at times, that the resin in part of the monocoque turns break during the building stage. In this case it should have to be mended. Note how I did it: The rear view mirror was already filed, sanded and polished, as we’ll see later with the metal parts. Then, it was glued firmly with abundant CA. If you’re inexperienced, I recommend to glue these parts right now, since once everything is painted, there will be no margin for any error!.

As in the real car, here the nose and monocoque will be attached by small bronze wire pins. It’s difficult to have them conveniently aligned, so in this picture, you will see the pencil marks of the position of each pin, then those positions were crossed and drilled very carefully where both lines cross between each other.

You must be very cautious, make small drillings and check the alignment every now and then. If you made any mistake, you should have to fill the hole with putty or CA gel and start again…something very tedious.

It’s time to decide about the antennas, pitot tube…etc that will be located on the monocoque, along necessary diameter of the holes that will be drilled. Then, pose them to check their positions. Have in mind, that paint will diminish the holes diameter and if the part doesn’t fit loosely, paint could come off the body, spoiling all this hard work, so make larger drillings (0,1-0,2 mm more) than the necessary ones, depending on the kind of paint you’ll use.

An aluminium tube was added to place the steering wheel, this tube must be concentric with the one seen in the picture, since it will be located inside it. The diameters will be according to those of the real car. I used 2 mm tube for the steering wheel and 3 mm for the monocoque.

Some PE may be located prior to painting, like in this case that they will take carbon fibre decal. They should be glued with CA liquid (cold, would be better) and you’d rather scrape them with a cutter to get a rough surface on the side that will be glued to the resin.

I drilled the holes where the tiny cooper nails would be inserted, to hold the windshield. As it was difficult to work in that position, I used a 0,8 mm drill, while the nail has 0,5 mm. This allowed me a margin to work comfortably. When time to place the nail comes, just you’ll have to pour a micro drop of CA in the hole, this will be enough to get the nail stuck.

See that, where the lower arms of the front suspension go attached, the monocoque doesn’t present the shape relying on the references. This was a simplification the manufacturer decided, to make easier not only the kit construction but the manufacturing as well. Look at your references, and you’ll check that, the bulge is continuous and the arms come out from their drillings.

In this picture you can appreciate how the quite notorious lack of accuracy was solved, you can see the continuity of this shape from the undertray to the nose. 3 mm aluminium tubes were placed, the remaining gaps were filled with polyester putty and sanded to shape.

Note, that the tubes were cut at an angle, to match the monocoque bulge.

Several sanding and priming sessions were necessary to get the right shape.

Furthermore, once the white paint (which acts as base for the red) was applied, several flaws came up and more sanding was needed in order to repeat again all this procedure.

I also drilled the holes for the bolts of this monocoque part. As the references showed, these bolts are not visible, so just make these drillings, it’ll not be necessary to place the bolts.

Obviously, the suspension arms were modified. You’ll learn how and the final result in Step 4 of part IV.

Finally, the body is ready to be primed. Look at the 2002 about to receive the first primer coat.

Here you have the 2003 with the base coat, I used Humbrol spray as primer, then, I began sanding and went on applying thin additional layers of primer.

The 2002 with the last white paint coat, sanded and polished ready to receive the red paint. Prior to painting, you must let it drying during a couple of weeks, so that the base adheres and cures properly, Then, it should be washed with soap and abundant water, leaving it dry thoroughly. Fortunately, resins don’t suffer electrostatic charge, not like plastic, at least.

The nose of the 2003. After a couple of white coats some flaws could still be seen on the surface, more sand (#600-#1000), and more paint were needed.

The workshop, you can see both bodies in different primer stages

To be continued…

By Mario Covalski
(Online magazine supported by HobbyLink Japan)

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