I'm guessing short of having a good straight clean bonnet to use as a plug to start with (the most expensive part) - the mold would also consume a significant space. For this reason I never went ahead with making one. In hindsight of course, I wish I had both the space and a good plug. I *had* a good bonnet, but didn't have space. I had space for smaller parts some time ago, but no longer.
Currently have neither as we are in the middle of relocating.
Fwiw, fibreglass would not be ideal, and there are a couple of reasons. One is weight, the second is the commonly available resins' suitability.
To achieve the desired strength, prevent sag and maintain a performance structure that will incorporate the crash protection structural component, the finished article in glassfibre would also carry more bulk than the sheetmetal bonnet.
Ideally, the most strength would come from a composite carbon-aramid lay up, which would need to be vac bagged and autoclaved. The reason for this is the resin used in this kind of application requires an elevated temperature cure process that is tightly controlled. The resin used has to withstand the target environment operational temperatures - and a basic epoxy or vinylester would not be sufficient in thermal stability for this application.
Lastly, you *could* in theory apply a thermal barrier to the underside- and a heat rejection foam/reflective material would possibly achieve this, but that in turn reduces clearance, adds mass and does little to assist with underbonnet temperatures - in fact likely would increase by a significant amount - which may in turn accelerate the perishability of hoses, wiring insulation and the like. It's a common issue in current model vehicles from all manufacturers and certainly was an issue with european manufacturing from the early 90's through to the late 2000's - ruining many a vehicle through engine bay thermal cycling and heat retention.
Great idea in theory - and completely doable. Careful material choices may get you there with the evolving technology in resins, but none of it is cheap, and carbon-aramid can be wet laid up... but you'd still need absorbtion mat, peel ply and vac bagging to get the correct material density and structural strength.
It always sounds easier than it is to actually do.
Then there is the cost.
You could buy a new part and have it painted up for less than ther cost of the above exercise.
You'd need to become a small manufacturing enterprise to make it cost efficient. by my estimate you'd need to manufacture about 20 units at the current price of a new pattern part bonnet before you broke even on the costs on the plug, mold and materials used to make the bonnet.
lastly - there are these guys...
Search: 1 result found for "range rover"
– The Fibreglass Factory
1050inc.
plus shipping.
for that $ I'd still go with a used metal one, even if I had to refinish it.
Roads?.. Where we're going, we don't need roads...
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