Hood scoops can make your car look like a muscle machine, whether or not you are making a bonnet scoop that is functional, or simply an added visual element. Hood scoops are designed to "scoop" outside air into the engine to provide additional cool air inflow to increase power. Even if you are making one just for looks, it will add the suggestion of road racing power to any car. Making a bonnet scoop is relatively easy and will only take you a weekend.
Lay your cardboard on the bonnet of your car and trace the size and shape of the bonnet scoop you want to make. You will only be drawing the top of the bonnet scoop, as if you were looking down on the entire bonnet.
Draw the sides and back of the bonnet scoop on your cardboard so each piece is drawn attached to the top view that you drew and forms a flat pattern. Make sure you angle the sides so the scoop will be higher at the front then at the back.
Cut out your pattern with a box knife. Then, score the cardboard along the lines where your side and back pieces connect to the top piece of your bonnet scoop.
Bend the sides and back down and tape them into position by placing a strip of duct tape along the seam. You should have a three-dimensional version of your bonnet scoop now. Place it back on the bonnet of your car where you want it and make any adjustment you need to the cardboard model until it sits perfectly flush on the bonnet.
Wrap your cardboard model completely in cling film and tape it in place.
Mix the fibre glass resin in your kit and saturate the fibre glass cloth that came with it as well. Lay the fibreglass on the top of your cardboard model and smooth it in place, be careful to work any air bubbles out from beneath the cloth before it dries. Make sure that you include a doubled strip of cloth along the bottom edge of your bonnet scoop that will lay flat on your bonnet, inside the bonnet scoop. Let the fibreglass set.
Remove the cardboard model from your fibreglass bonnet scoop. On the strip you placed on the bottom edge, mark and drill holes for bolts. This will be how you bolt the scoop to your bonnet.
Mark and drill holes through the bonnet of your car that match the holes in your scoop. Insert bolts through the scoop and attach to the car. Then glue your metal grill into place on the front of the bonnet.
To make it real, cut a circular hole in the bonnet of your car beneath where the bonnet scoop will be placed.
While there are many adhesives on the market advertised as being strong enough to affix the entire scoop to the bonnet of your car, the risk you take in the glue failing and the scoop coming free and causing an accident is too great to consider this short cut.