Carbon Fibre Body Panels

General Composites Discussions Showcase
#1

Its not very oftern that I can post pics here of work that I do for customers, but this one I can.

Here are a few pics of some panels that we did a couple of weeks ago there is a roof panel that has an outer skin and an inner skin that are secondary bonded together and an engine cover panel. They are to fit a Lotus Elise/exige race car and have been modified from the origional Lotus items following some aero testing.

All of these parts are 100% Carbon fibre with Nomex Honeycomb used in some areas, using epoxy resin and are ‘wet layed’ and vac bagged then cured at elevated temperatures.


IMG_4141 by dobsonm, on Flickr
The roof outer skin viewed from the rear.


IMG_4139 by dobsonm, on Flickr
The top side of the roof outer skin (viewed from the front edge)


IMG_4111 by dobsonm, on Flickr
The Engine cover panel that sits in the middle of the rear clam shell.


IMG_4110 by dobsonm, on Flickr
A close up of some of the detail around the badge on the engine cover.

Please DO NOT copy or repost these pictures in anyway on another website, doing so may result in me having to stop posting pictures on this forum. I have to get permission form my customers to be able to publish any of my work so please respect this.

I hope that you enjoy these Pics.

#2

looks like you did a nice job! Keep up the good work!

#3

Parts look great. :slight_smile: Did you use a gelcoat or is it just cleared with a top coat?

#4

Took the works right out of my mouth. Great job Matvd!

#5

The parts have been clearcoated. It isnt something that we usually do as most of out work gets painted but these parts arnt being painted so got clearcoated as they will remain exposed.

#6

how do you get your parts free of pin holes; or were the pin holes filled in with clear coat? Does oven curing take care of pin holes in the part surface?

#7

Lovely work :slight_smile:

I see you got some very tight radii on those parts, do you have to pay any special attention to those areas? every time I attempt parts with such radii I get misty edges that are full of tiny air bubbles, which I suspect are caused by bridging. I have tried using different bagging films(ie normal vs stretchy), using a caul plate made of rubber(did not work, but I believe the vinamould red was too soft, so now going to try the yellow harder type) Would love to know the products and processes you are using :slight_smile:

#8

The tight radii areas do require special attention. Basically it is down to being very carefull with the bagging. Pressing the bag into the corners. Having pleats in these areas and using wedges to push it into these areas. I will post a pic of that tomorrow when im back home at my computer that has pics of that on it.

The parts out of thr mould do have slight pin holes but not bad by any means. Flatting the parts to clearcoat actually opens up more pin holes! This is then cleared with the clearcoat.

The parts are rubbed down with 400 grit. Then clear coated. Then flatted again with 400 grit wet and dry and. coated with clearcoat again then 1500 wet and dry and polished. Thats it.
I use a 2k automotive clear coat.

#9

So to get this right, you made the part raw, blocked it down and then 2K cleared and blocked until the pinholes were gone? Did you do a resin coat and let it tack up before laying the first layer of CF or did you just put down the CF and start wetting it out? Thanks for the answers. Pinholes were exactly where my question was headed as I’m sure I’ll be up against this battle soon. :slight_smile:

#10

Sweet!!! Great looking Job!!!

#11

As I said earlier I use wedges to push the carbon into the tight radii


IMG_4123 by dobsonm, on Flickr

Using wedge to press carbon fibre into the tight radii. Lotus Elise inner skin


IMG_4121 by dobsonm, on Flickr

Using wedge to press carbon fibre into tight radii.


IMG_4129 by dobsonm, on Flickr

Lotus Elise roof vacuum bagged.
Pulled down to 29.5Hg, performing a vacuum check prior to being cured at elevated temperatures.

#12

were do you get the wedges from ? i have a roof to do , ive just done a mould , what resin do you use , as ive only done small ish parts so far

#13

Great part! Especially on the edges, and no distortion in the fabric.

Could you tell us a bit about the wet laying technique you are using?

Did you impregnate the fabric inside the mould? Or maybe outside of the mould like the homemade prepreg?

Can you show the mold side of the part after demoulding?
What kind of viscosity does the resin have?
What was the weight of the bleeder?

Sorry for all the questions, but a while back I was doing some wet lay up with vacuum assistance, and I had crazy print through. I was trying all kind of variations in my set-up and the only really nice part I made, I used a thin glass fiber layer for the first layer.

#14

I get the wedges from ECF here in the UK, i buy the long ones then cut them to the size that I want, yjey are made of rubber. I also use some plastic wedges that I make my self.

The resin is from Polyfibre here in the UK, I use that one as it has a high TG (150 c) and a long pot life.

I place the cloth in the mould then wet out in the mould, being very carefull about the amout of resin that is used to keep the fibre ratio as good as possable.

#15

Could you elaborate a bit further on your technique? What fibre ratio do you aim for? Do you lay a gelcoat in the mould first? and Do you wet out each layer or place them all in the mould first? Sorry I have so many questions :slight_smile:

#16

Very nice. What do use to post cure? Did you make an oven setup?

Thanks for sharing.

#17

Marc, I try to aim for a 55% fibre ratio, I can get very close to this after the breather cloth has taken in a little bit of the excess resin, when I am measuring out resin and laying up I mix enough resin to get a fibre ratio of 50% ie the same weight of resin as the weight of cloth that I am laying up.

I generally do not make ‘home prepreg’ I place the cloth in the mould then wet it out one layer at a time.
There is NO gel coat on these or any of my CF parts because I mostly make parts for race cars that need to be as light as poss and they get painted.

#18

Noob question whos crap at maths!

Whats the calculation to work out how much resin required per mold/laminate?

#19

I used a heat blanket set up on this as I can not fit these moulds into my oven due to there size. They are cured at 65 deg C using my heat blankets. I only have a fairly small oven at my shop, I have access to a large oven when I need it.

#20

Link to heat blankets or similar? I assume you don’t use ones for beds!