Page 38 - Australasian Paint & Panel Magazine Sep-Oct 2019

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Winning formula
PAINT&PANEL SEPTEMBER / OCTOBER 2019
WWW.PAINTANDPANEL.COM.AU
The tub is essentially a survival cell for the driver and made up of around 30sq metres of carbon fibre mats. Each of the fibres is five times thinner than a human hair but they have supernatural strength. Washington reveals: “These are so resistant to accidents that in 10 years we’ve only had to throw one tub away. We always repair these when we can.” Even though a car may look pret- ty smashed up, once damaged compo- nents are removed from the outside, the tub is frequently untouched.
SUPER STRONG
SURVIVAL CELL
That’s a good thing, for the team as well as the driver’s wellbeing. Up to 60 layers of carbon composites are used in places on the survival cell. These are high-den- sity woven laminate panels covering a strong, light honeycomb structure in- side. Its flanks are protected by a 6mm layer of carbon and Zylon, a material used to make bullet proof vests. This is to prevent objects or debris from acci- dents entering the cockpit.
The three main components used in the composites of F1 cars are rayon, pitch and polyacrylonitrile. These are then baked in an oven at temperatures up to 1800 degrees C. To give an idea of its strength, McLaren once loaded a 10mm strip of 1.3mm thick carbon fibre into its rig and progressively increased
the weight on it. It wasn’t until this small sample was under 4.5 tonnes of pressure that it failed structurally.
With the use of spare cars banned from Formula One, McLaren now only uses four tubs for the entire season (as- suming none are destroyed). “We re- paint the tubs every three races, de- pending on where we are in the world,” explains Washington. “We take three tubs to each grand prix, and just take one out of the pool and put another one in. It’s a case of juggling them around, with the team manager working out which gets painted and when.”
Immediately following a race, the cars are taken apart and the tub to be repainted and bodywork make up an el-
ement of the 30-tonnes of parts that are air freighted back to the UK. By the Tuesday afternoon following a race, the refurbishing process for the next race will begin.
ULTRASONIC TESTING
This starts with around 200 parts, in- cluding the tub, undergoing an ultrason- ic crack test. With crack depth levels measured too, this scan tells the team which parts can and can’t be reused. Af- ter this, Washington and his colleagues get their hands on the parts that can be reused, plus any replacements. “We have hundreds of new parts throughout a season so the paint shop is a pretty busy place,” he says.
To start with, Washington’s team painstakingly strip the paint off by hand. “This is so we don’t damage the structural or aerodynamic integrity of the parts,” he says. And then there are the new parts. “We’ll receive a new com- ponent from the composites assembly department and it will have been fabri- cated in bare carbon. We’ll flat the whole thing off with some high-grit sanding, abrading the surface and key- ing up the areas that need to be painted. Some surfaces that are part of the aero- dynamics are left completely unpainted because it makes them less air resistant.
“Once we’ve finished sanding, we’ll start to apply filler to make the whole surface smooth. But we don’t fill too much because we don’t want to change the shape of any aerodynamic compo- nents. We’re looking for imperfections in the carbon, or the step-joints where
THIS PAGE: With the use of spare cars banned from Formula One, McLaren now only uses four tubs for the entire season. The tubs are repainted every three races.