CF Fenders vs Composite

[CBuff]

Hello all,

 

I am starting down the path and have an oder slot for February 2023 for a 420R SV. One (one many) items I keep flip flopping around on is the fenders. 

 

I like the look of body colored fenders and rear wings. I have read that the composite (form of fiberglass?) can spider from stone hits both above and below. Was thinking of coating the underside of the fenders with truck bed liner or similar, and have PPF on the tops. Or go the more expensive route and have carbon fiber fenders painted the body color with just PPF on the tops. Also whats the feeling on the stone guards on the rear fenders? Is PPF enough or do both, again prefer the cleaner look. It seems like track driving can add some rubber marks to fenders without stone guards (Thats why I assume they are black) but I believe this can be taken off relatively easy. Please correct me if I am wrong. 

 

Likely overthinking things but it wont be the last time I am sure. 

[kayentaskier]

I have a 2020 420R, it just rolled over 4kmiles on the odometer. When Josh Robbins built my car he added truck bed liner on the underside of the painted fiberglass wings, he also added PPF to the top of the wings (and other areas). The CF stone guards remain on a shelf in my garage. I had unpainted CF wings on previous Caterhams and was dissatisfied at how quickly the CF was damaged by exposure to UV. So far no indication of spider cracks. My car is used only on the road.

[MV8]

CBuff, composite is the method of assembly. The material is either fiberglass or carbon fiber. The binder or "matrix" of the material is usually epoxy but traditionally polyester resin and both work well. I'd have bare CF clear coated or FB undercoated.

[KnifeySpoony]

IMO front wings are an aesthetic choice, as they don't get that much abuse. I have CF front wings without PPF on them, and they are holding up just fine. If you went painted CF front wings, I would do PPF on them to minimize chips. WRT rear wings - they get HAMMERED, street and track. I have painted fiberglass rear wings, fully PPF'd underneath the standard CF stone guards. After de-rubberizing them (Mothers R3 is great for this), they still look new. With painted rear wings (either glass or CF), without PPF or stone guards, they will get sandblasted in no time. In cars with stone guards but no PPF, the exposed lateral edge of the wing next to the stone guard takes a beating; PPF is your friend here. Rear tires definitely kick up a lot of stones on the underside of the wings - I did 2 thick brushed on coats of truck bedliner during my build and with about 2500mi and 8 trackdays on the car, there are a number of big chips in the bedliner, but no cracks in the fiberglass yet. I think a more "rubbery" product might give superior results, or maybe I should've done more coats.

 

Oh also, I recommend full PPF on the nose cone if you wish for it to keep its paint.

[Croc]

Question: Do you prefer painted look to the wings or carbon fiber look?

 

Option 1 for painting, figure on getting LineX or bed liner fully coated under the wing and 3M film on top.  The 3M film will look a little tatty after 5 years and a spider crack from a rock is going to get through the 3M film - not much you can do about it.  

 

Option 2 for painting is get LineX or bed liner sprayed under/inside the wing plus on the front facing half of the rear wing.  It will weigh a ton but will protect them much better.

 

You can paint carbon fiber BUT it depends where sourced from.  The Caterham carbon fiber is usually not sealed.   Paint (or clear coat) sinks into the weave, producing a dimpled effect.  It takes a lot of coats and sanding to get it looking smooth.  You would be better off leaving the the carbon fiber unpainted.

 

If you prefer the carbon fiber look to front and rear wings then get the 3M film put over them.  It will protect them from chips and seal them from moisture.  My rear wings are 12 years old and still looking decent under the 3M film.  Film is getting a little tatty on the rear wings and needs redoing which is next years plan.  

[CBuff]

I do like the look of painted vs the CF. I think I will bedliner the underside and PPF the tops. I can replace the PPF as needed and if it gets real torn up I can explore a repaint or replace the rear wings. 

 

As far as PPF, whats the thinking on that. Just the high hit areas or do people do the entire car? Would you ever double up on the rear fenders? Likely being a little over protective as I click the option boxes and want this to stay new looking. I am sure once I am driving it I will be less worried about things. 

[KnifeySpoony]

I have the full nosecone, side panels and rear wings PPF'd and it's doing great protecting it on track. The side panels and rear wings get absolutely covered in rubber marks but I only see only a few tiny nicks in the PPF on the nose and rear wings from meaner rocks. The PPF also gives some peace of mind when using more aggressive methods to de-rubberize them. 

 

If you want keep it looking fresh i think my PPF strategy is the minimum tbh. 

[KnifeySpoony]

Here's a pic of the rubber on side panel after a few trackdays. Imagine the stone chips...

Edited August 1, 2022 by KnifeySpoony

[CBuff]

Knifeyspoony,

 

That’s super helpful. I wouldn’t have thought you would get that much on the sides.  I will likely air on the side of more coverage.  
 

Many thanks. 

[Croc]

10 hours ago, CBuff said:

As far as PPF, whats the thinking on that. Just the high hit areas or do people do the entire car? Would you ever double up on the rear fenders? 

 

I only did the wings in the 3M film.  Hindsight says I should have done the nosecone and the sides - lots of stone chips and road rash.  My next Caterham will 3M those area.  

[Bartman]

@knifeyspoony I am curious, did you cover the whole cone or just the leading edge "bra style" ?I took the my CF nose cone to three different PPF guys here in MD, all refused to do it saying they could not get the PPF to conform properly to the shape of the nose. I decided to try out the spray-on PPF, it came out pretty nice a little duller but still good looking, it took 10 coats of the stuff to build up the thickness required. I will PPF the rear wings myself in the next few weeks with traditional 3M film.  

[KnifeySpoony]

Ah yes - there is a small area on the lower/side near the back of the nosecone on each side that could not be covered due to excessive slack in the film. The installer did a small curved cutout in the film that is hardly noticeable. All of the front facing areas are covered.

[Mark IV]

We suggest Rhino Lining for the underside. It is a "softer" material than Line-X so it absorbs the impacts better. We have had PPF installed on a few cars to the customer specification, everything from an almost total wrap to just wings. Several have done the lower sides to eliminate damage from the front tire stone throws.

[Vovchandr]

I'll throw a wild card alternative into the ring that I use

 

Adhesive backed rubber

 

Product similar to this

 

https://www.amazon.com/DOBTIM-Adhesive-Non-Slip-Insulation-Padding/dp/B08Y7N9652/ref=sr_1_3?keywords=adhesive+backed+rubber&qid=1659536994&sr=8-3

 

I just rolled out the sheets and stuck them inside the wheel wells and don't drive in the rain (although I think they would survive just fine if needed)

 

Helps with noise and damage.

[magazineman]

Here's a wilder card than that:   I removed my Birkin S3's front fenders and their support brackets 12 years ago.   So I'm running Open Wheels in front.   Here's a few of the advantages:

 

1.  A lot of un-sprung weight gone.   That created a noticeable improvement, especially on imperfect sections of road.  

2.   NO MORE front end lift at high speeds. Triple-digit speeds were pretty hairy before this mod!    

3. Autocross ----- I can see EXACTLY where my tires are. 

4. No fender damage ------ they are in perfect condition up on the rafters of my garage !! 

 

Downsides:  Gravel in my hair.  And , I suppose, rain would be a drag but I use other cars in rain anyhow.  That's why I have no windshield or wipers.  Basically, I have noticed that the more stuff you remove from a 7 , the better it gets.