Elise construction?
Discussion
So please excuse the daft question but... Elises are constructed of aluminium with a grp body yes? I was confused by this aluminium nose on eBay. 
rich... http://cgi.ebay.co.uk/Lotus-Elise-Exige-S1-Front-Bon
rich... http://cgi.ebay.co.uk/Lotus-Elise-Exige-S1-Front-Bonrichb said:
So please excuse the daft question but... Elises are constructed of aluminium with a grp body yes? I was confused by this aluminium nose on eBay.
Gues he ment New Aluminium paint color,but indeed very confusing
For the Caterham 21 there where made some complete alu body's though...but almost never heard about the caterham 21 again...there are also some great 21GTO's coupe's in Belgium with a 230hp K-series jummie
Correct me if I'm wrong, but one piece is made of normal steal, I believe the rear subframe?? or something for the engine? or am I confusining it with another car...
GTRene
>> Edited by GTRene on Saturday 14th January 13:30
shangani said:
It is either a custom item that he has had made, or more likely he is referring to the colour. The bonnet / bodywork, doors etc are all GRP. (fibreglass basically) All of this is bolted onto an extruded aluminium chassis.
Sorry - I should have qualified - I was referring to the S1. Bogie is quite correct in terms of the way it is laid up between the S1 and S2.
>> Edited by shangani on Saturday 14th January 16:52
The materials are essentially the same - Glass reinforced plastic is essentially fibreglass. There were differences in the way the S1 body was constructed vs the S2
S1 bodywork:
These are made from Glass Re-inforced Plastic (GRP) (frequently called fibreglass) in a 'hand laid' process, at the Hethel factory. This process was used for because of the cheaper tooling costs associated with the limited production run (originally estimated at 700 cars per annum). The tooling was actually being used to produce 3000 cars per annum and was becoming very worn towards the end of mk I production. This process is manually intensive and relies on hand laying of fibre glass pieces into the mould with a 'gelcoat' used to stop the fibreglass sticking to the mould. This gelcoat is not completely removed however and a minor impact can cause it to crack into a spiders web of cracks under the paint finish. A lot of hand finishing was then required to remove the majority of the gelcoat and clean up the produced panels, ready for painting. This results in a panel with a rough mat finish on the inside. This was a fascinating process to watch in action on the factory tour. A very high pressure water cutter is used to cut the apertures in the clamshells and to do some of the edges. The doors skins, boot, bonnet and boot lining are also produced in this way, though on early cars a boot bag and an aluminium boot lid were used.
S2:
A greater number of smaller panels are made in chromed steel moulds and injection moulded. This allows thinner panels to be produced with localised bonded panels attached later to strengthen particular areas. The use of closed moulds means that the panel shape must be such that it can be extracted once formed, i.e. no re-entrant features. In fact some small re-entrant features exist using sliders within the mould. Both the front and rear clamshells are made from two main pieces which are bonded together at Hethel in special jigs to make a complete clamshell. This new process does not require a gelcoat so gelcracks are a thing of the past.
The difference is in the process. The actual fibre matting (fibreglass) will be the same material. This can be substituted for carbonfibre laminates etc, but then the process becomes far more complicated, requiring oven baking etc etc.
>> Edited by shangani on Saturday 14th January 16:31
S1 bodywork:
These are made from Glass Re-inforced Plastic (GRP) (frequently called fibreglass) in a 'hand laid' process, at the Hethel factory. This process was used for because of the cheaper tooling costs associated with the limited production run (originally estimated at 700 cars per annum). The tooling was actually being used to produce 3000 cars per annum and was becoming very worn towards the end of mk I production. This process is manually intensive and relies on hand laying of fibre glass pieces into the mould with a 'gelcoat' used to stop the fibreglass sticking to the mould. This gelcoat is not completely removed however and a minor impact can cause it to crack into a spiders web of cracks under the paint finish. A lot of hand finishing was then required to remove the majority of the gelcoat and clean up the produced panels, ready for painting. This results in a panel with a rough mat finish on the inside. This was a fascinating process to watch in action on the factory tour. A very high pressure water cutter is used to cut the apertures in the clamshells and to do some of the edges. The doors skins, boot, bonnet and boot lining are also produced in this way, though on early cars a boot bag and an aluminium boot lid were used.
S2:
A greater number of smaller panels are made in chromed steel moulds and injection moulded. This allows thinner panels to be produced with localised bonded panels attached later to strengthen particular areas. The use of closed moulds means that the panel shape must be such that it can be extracted once formed, i.e. no re-entrant features. In fact some small re-entrant features exist using sliders within the mould. Both the front and rear clamshells are made from two main pieces which are bonded together at Hethel in special jigs to make a complete clamshell. This new process does not require a gelcoat so gelcracks are a thing of the past.
The difference is in the process. The actual fibre matting (fibreglass) will be the same material. This can be substituted for carbonfibre laminates etc, but then the process becomes far more complicated, requiring oven baking etc etc.
>> Edited by shangani on Saturday 14th January 16:31
bogie said:
actually moulded composite fibre on the S2 - the S2 Exige and S1 is hand laid GRP though
Fibreglass is fibreglass...regardless of whether it is hand laid, spray moulded or VARI injection moulded.
Composite fibre is a broader term, encompassing GRP, carbon fibre composite, kevlar composite etc., or a mixure of several different reinforcements. As far as I am aware, the vast majority of the S2's bodyshell still uses plain old fashioned glass fibre as the reinforcing material, albeit using more sophisticated lay-up techniques?
>> Edited by Sam_68 on Saturday 14th January 16:40
I think you are right Sam,
All GRP.
I think the VARI technique was used in the S1, certainly for the side sills, screen surround and, I think, the hard top.
Even with the VARI technique, the glass fibre is still put into the mould by hand (albeit dry). It is only the resin that is injected.
I think the main advantages are, increased accuracy, quicker cure times (steel tools can be heated) and cost savings by using fillers in the resin.
The rest (clams etc) was made using the low-tech, traditional, messy lay-up
I'm guessing more of the S2 might be made using VARI?
Dunc
All GRP.
I think the VARI technique was used in the S1, certainly for the side sills, screen surround and, I think, the hard top.
Even with the VARI technique, the glass fibre is still put into the mould by hand (albeit dry). It is only the resin that is injected.
I think the main advantages are, increased accuracy, quicker cure times (steel tools can be heated) and cost savings by using fillers in the resin.
The rest (clams etc) was made using the low-tech, traditional, messy lay-up
I'm guessing more of the S2 might be made using VARI?
Dunc
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