CF rear subframe?

Post by **RattyMcClelland** » Thu May 10, 2012 11:00 am

Carbon fibre isn't strong enough with resin etc. It needs a vacuum and 900degrees to be close like f1 cars.

A1ex · Post by **A1ex** » Thu May 10, 2012 11:02 am

The Maclaren uses resin. It's vacuum formed and baked at around 80 Degrees C.

I saw 'how to build a supercar' at christmas time, they took you through how they build the whole car in the Maclaren factory.

Post by **Ammo** » Thu May 10, 2012 11:05 am

RattyMcClelland wrote:Carbon fibre isn't strong enough with resin etc. It needs a vacuum and 900degrees to be close like f1 cars.

You use a core of foam etc, I'm assuming that A1ex is making his parts the proper way with vacuum and baked in an oven. Few layers of carbon and it's way stronger and super light

A1ex · Post by **A1ex** » Thu May 10, 2012 11:11 am

Ammo wrote:
RattyMcClelland wrote:Carbon fibre isn't strong enough with resin etc. It needs a vacuum and 900degrees to be close like f1 cars.
You use a core of foam etc, I'm assuming that A1ex is making his parts the proper way with vacuum and baked in an oven. Few layers of carbon and it's way stronger and super light

The core of foam is to get the active surface of the fibre further from the centre of the part where the bending moment acts. The same principal is applied with steel 'I' beams.

My current process for the asthetic parts isn't vacuum & oven sadly. They cure in my dad's conservatory at around 50 degrees, when it's not raining, and they're compressed with a rigid mould, negative mould & g-clamps. That's as close as I can get without buying the vacuum kit, but if I was to make this part I would be getting the full kit for it

We also have a pull test rig in work so I could test the axial strength of the part compared with original.

Post by **RattyMcClelland** » Thu May 10, 2012 12:01 pm

Also you need very high pressure and its closer to 900 degrees IIRC. Below this carbon is brittle.

Post by **Ammo** » Thu May 10, 2012 12:44 pm

no it's not

Post by **RattyMcClelland** » Thu May 10, 2012 1:30 pm

In comparsion to steel its very brittle. That's one of its properties.

mercutio · Post by **mercutio** » Thu May 10, 2012 4:36 pm

no i didnt say it wasnt as good as steel just the f1 parts are constructed to take only certain stresses not the multitude that a road car has to take lets face it you bump wheels in an f1 car and you can smash the suspension arms, because they are designed to be as light as possible so only designed to take stress in a certain direction.
Thats what i meant i know supercars are made of the stuff but they are baked in huge autoclaves (sorry for using the word baked) to produce the required strength.
Honestly mate if you could produce the stuff i would buy it from you in a heartbeat being such a carbon whore

it was one of the reasons i bought the 5th i have always wanted a complete carbon interion all the door panels and roof panel i know it wouldnt be a nice place to live if i wiped out lol but i dont care.

A1ex · Post by **A1ex** » Thu May 10, 2012 5:13 pm

You've hit the nail on the head there, the stuff performs to it's design spec. If it is designed to take the abuse you get on the road it'll take it.

The final summary of my dissertation was that with the right orientations & layup CF parts can behave in the same way as metal parts and take forces in all planes as metal parts can. Within the last couple of years a leader in the CF research field release a lengthy paper on this exact topic that with the correct design CF parts can be given metallic unidirectional load baring properties

Anyhow, if I were to make a part like this it would be made with all the right tech and tested before use. I wouldn't just stick resin on some carbon fabric and hope for the best.

secla · Post by **secla** » Thu May 10, 2012 5:24 pm

I was under impression that the only way to make strong carbon fibre products is with an autoclave which is very expensive. I don't think you would ever get the strength needed for a structural piece from wet lay up.