Carbon Fiber Hardtop - from China

[PaulF]

Consider just using some plates to bolt the hard top down at the sides. OMGPham sells them, as does AGI (the roll cage manufacturer) in Sydney.

[Mr Morlock]

no Sailholic- you are getting mixed up with a few common ingredients which is not the same as processes and the chemistry behind it. Laying up fibreglass is a fairly crude process often with poor control of tolerances and often used for low production items and very labour intensive. Even smc and dmc are not big players in the automotive world because injection moulded thermoplastics are far better suited to volume, cycle time and also able to be reground. The point is hat the OEM hard top was a well engineered product not just used as a pattern for a knock off and calling the oem hardtop fibreglass is not accurate.

[hks_kansei]

Having repaired an OEM hardtop I can say that the internal panels are indeed fibreglass of some form.

They've got the typical fuzzy fibres embedded in resin. (when broken it has the ragged edges etc, and itches like mad)

The exterior though, is a far different thing. When it's broken there are no visible fibres or ragged edges.


I have no idea what it actually is, but it's more like hard plastic than fibreglass.

[sailaholic]

No morlock you are getting mixed up : with the difference between material family's, generic names, material specifics and production methods

Fiberglass is generic name for glass fibre in a polymer matrix.

They are many variations on the ways of which to make a product with these two materials.

The glass fibre can be in a woven mat, it can be spun on a mandrel as a long continuous filament or it can be chopped strands.

The polymer can be applied as wet as a 2 part mix as used in wet lay up or it can be thermoset as used in pre-pred vacuum bagging materials or it can come in bulk with the fibre pre mixed in.

SMC is large sheets of chopped stand fibre is a thermoset polymer matrix when can then be compression formed and cured through heat.

Ambiguity can exist in that SMC is also used to describe the process and aramid (Kevlar) or carbon fibres could be (but rarely are) used in place or glass fibre. However these would then still be sheet moulded Kevlar or sheet moulded carbon.

To look at another way.
There are many types of steel: alloying elements, strengths, elongation to failure, fracture toughness all change but they are still all from the family or material called steel.

SMC is still fibreglass, the forming process used may have been a world first, the method of putting the glass fibre is the matrix might have been world first but the material is still glass fibres in a polymer matrix.


Sent from my iPhone using Tapatalk

[Mr Morlock]

Sailholic said- "SMC is still fibreglass, the forming process used may have been a world first, the method of putting the glass fibre is the matrix might have been world first but the material is still glass fibres in a polymer matrix" You clearly are aware of the processes but its a great simplification to describe the product as fibreglass. Glass fibres in a polymer matrix it sure is but how that is done and what process is a long way from a backyard operation with little science and no testing or rigorous quality control is applied. You can bet cos like CME retain test data and often test plaques. Polyprop or nylon can contain glass fibre as well as any chemist or plastics guy knows and thermoplastics are often just called plastic but the variety to experts and the way they perform is significant. Incidentally chemists always struck me as very smart guys - good thinkers and terrific with processes and logical thinking.

[shuey]

.. sooooo, have we come to an agreement or agree to disagree?
too.many.words. need

[sailaholic]

We agree the factory top is made from fibre glass, we just disagree on wether it should be labelled as fibreglass.

.


Sent from my iPhone using Tapatalk

[orx626]

As far as I was aware the OEM hardtop is FRP - Fibre Reinforced Plastic.

[hks_kansei]

As far as I was aware the OEM hardtop is FRP - Fibre Reinforced Plastic.

That would match what I found on the broken top.

Outer was very plastic like, I couldn't see any glass fibres (I assume they must just be really small, almost powder like?)

Inner was just normal fibreglass though.

[vv4rhead]

These don't come with windows do they? Where can we get windows for them?

Curious because carbonmiata is selling the fibreglass variant for $600, seems like a cheap way to get a hard top?

[madjak]

These don't come with windows do they? Where can we get windows for them?

Curious because carbonmiata is selling the fibreglass variant for $600, seems like a cheap way to get a hard top?

Mine comes with a window, or rather should have. The hardtop arrived last week with no rear window, speaking to my Chinese contact it has now been shipped separately.

The hard top is really nice, very light and well made. It must weight less than 5kg all up. Basically there is a CF outer skin and a fiberglass inner skin and it looks a direct mold from the OEM hardtop. Once I have fitted the rear window I'll weight it and report back.

In terms of fitment, I had drill out the rear mounting tabs to fit over the frankenstein bolts but other than that, all the trims have just bolted on and it fits well. I have used the seals and mounting hardware from my softtop which basically just bolted straight onto the hardtop. I am ordering some light weight side and top plates to hold it on but for now it's in place as I'm using this car for track events and don't want it blowing off, plus it doesn't need to be quickly removable. I have also board a strip of rubber to fix to the rear of the hardtop where it sits onto the body.

Overall I'm very happy. Looks great on the car.

[gslender]

Pics?


Sent from my iPad using Tapatalk HD

[Apu]

Just reviving this thread as I'm still keen on a CF hardtop.

Madjak, any further news / updates / reviews?

[madjak]

Just reviving this thread as I'm still keen on a CF hardtop.

Madjak, any further news / updates / reviews?

Yeah sorry, I've been busy!

I have now mounted the rear window and so it is all finished and mounted to the car. It looks excellent and I am really happy with it. The hardtop leaks a little over the windscreen but I think that is more due to the old rubber trim that I recycled from my softtop rather than the hardtop not being the right shape.

The only other issue is the rear window cracked a little when I was mounting it. At first I a very sharp drill when I drilled the holes for the screws and it bit and grabbed. So I changed to a smaller drill and countersunk each side of the lexen then drilled it out larger for the mounting screws. That worked fine for all but the first hole, and when I tightened the screws, it cracked around 20mm or so. I ended up drilling the end of the crack to stop it progressing, and since then it's been fine.

The outer layer is laid up as one piece of carbon fibre so there are no visible seams. Inside there is a fiberglass skin that is separate to the outer skin. It looks like these are made separate and then joined together. The outer layer is very thin and pushing on the roof will deflect it in. There are a few little dents on the top at the front that I made when I was fixing the rubber seals or when I clamped it up. Over the past few weeks they have reduced down to be only visible when there is a straight reflection line running through them.

Overall for a lightweight hardtop I'm very happy with it. My car isn't being parked in the sun except on track days and I would probably not recommend it if using it for your daily driver.

I used it a few weekends ago up at Barbagallo and on the track it was fine. My helmet just rubs on the top but I assume all hardtops are the same in that regard. Once I fasten my harness and it pulls me down into the seat there is no issue.

I have attached a few pictures taken of the hardtop. I don't really have any out in the sun but I'll make sure I get some better pics when I'm out next.

[bruce]

Me likee!
Thanks for the pics and feedback.