What to do about the diffusers on the 355?

The NACA ducts are for cooling the brakes via hoses. The clutch housing is drilled as shown and the clutch heat shield/cooler directs cooling air to the clutch...
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Better to have a little less aero but have working brakes at the end of the straight .

 

I believe my transmission cover is carbon but now I will have to check.

 

All oem parts are manufactured first with a gel coat sprayed in to the mould followed by the fiberglass cloth and resin.
This ensures a smooth final finish where either colour is impregnated into the gel and/or a painted finish coat is added afterwards (ie for fiberglass fenders which need to be painted numerous colours). This has been the standard for over 30 years.

 

Some people use bondo to finish the fiberglass for painting.....takes less time to complete the repair.
What I do is finish the fibreglass to a final near perfect state and then add the gel coat for the final finish ....as per OEM.
Painting ensures colour uniformity as I can spot paint/blend the nearby panels for a perfect finish.
When any area is repaired you should not be able to see where the new vs old finish starts.

 

Agree.

The OP was querying repairing a damaged piece most likely originally fabricated using this method. He wasn't clear on what gelcoat is.

In doing a repair on a boat hull the top finish would be gelcoat , not primer and paint. Being as the gelcoat would be applied on the top as opposed to the original fabrication process being gelcoat first in the mold followed by FG, the repair is tricky.

If these diffuser panels are being acceptably repaired using paint and primer on top of a FG repair then so be it. But if the OEM process was traditional FB fabrication then gelcoat ( pigmented epoxy resin) is the OEM finish. Not primer and paint.

 

ok

 

CF what primer and paint have you found works well?

I think trying to match using gelcoat only is onerous and under the car may be overkill.

I have one rear diffuser that was repaired and sprayed with some sort of rubberized goop that I would like to upgrade.

 

I expect the goop is rustproofing from the Ferrari dealer. When ever the car went in to service they would spray this stuff liberally.
The primer I used was : Transtar Autobody Technologies Inc #4613c ( black primer that can be used on flexible panels).
The paint I used was: Dupont , semi matt (didn't have any left so I don't have the part # from the automotive paint jobber).

 

Exactly. It is this dull black. Rubbery goop. It is over sprayed in some areas as well. I have tried to cut it with acetone, gasoline , paint thinner etc. All to some degree but it sucks.

What would cut that junk to remove it and do a more finished repair?

 

I would try automotive paint grade lacquer thinner...but where rubber gloves as it will take all the moisture out of your hands

 

Take a look at Eastwood Company, they have a special spray product for removing this goop. Unfortunately nothing works easily with that crap. Make sure you have plenty of rubber gloves.

 

Most likely rubberized undercoat or a product called "chip guard" or called body Schutz

Yes its used to "hide" imperfections and prevent rust

Warm slightly then try a putty knife maybe a plastic putty knife

I hate removing that stuff

 

My diffuser needed some repairing. The fiberglass is very thin and fragile. Once fully repaired and smoothened with filler/primer, i will be make a mild out of these so I can build them carbon fiber. I mentioned in the challenge wing thread I own a composite manufacturing company, so I am very familiar with the building process and repair.

I believe the Diffusers are a gel coat finish. It is possible Ferrari might have sprayed a finish on top of the gel coat (it is difficult to tell with debris build up) but it certainly wasnt a paint (base coat + matte clear coat) finish. Gelcoat is a semi-robust finish. Better than spray can psint, but not better paint. As mentioned above, gel coats are applied (sprayed or brushed) onto a smooth (preferably) mold surface. When the part is pulled, the gelcoat surface reflects the mold surface. It is a cost effective way to apply a semi-robust finish to a part during a manufacturing process as opposed to make a oart, sanding, primering,sanding, painting. Gel coats are very thick unlike paint. If you want a conformed and not a patched-up look, you need to spray or brush the gel coat onto the entire diffuser. Be prepared to do ALOT of sanding and polishing to cut the gel cost surface down.

 

Another thing to consider, most damages are done to the fins. Eithera chip or a chunk missing. A repair with fiberglass and resin would be done opposite of the gel coat finish side of the fin, which is exposed. You will be able to see the patch work from the side of the car.

I asked for pictures because i wanted to see the extent of the damages. Once i have the mold, it will make it easier to do repair work on these diffusers. All i have to do is slide the damaged diffusers into the mold and patch and add fiberglass (extend) where needed. However, patching will be seen but i might have a way to fix that. I still higly recommend painting the diffuser or spray painting it. Gel coating will require labor extendive work to get it to look smooth and semi-shiny. I can apply a gel coat for you, if youre up for the sanding and polishing. I wont have time for that.

A side note. You can improve aerodynamic efficiency if the surface of your undertray/diffuser is extra smooth. Either through waxing, a smooth painted surface, or carbon fiber with a smooth clear coat finish. Faster and smoother airflow under the car = more downforce.

 

Nice work!

 

Nicely done!

 

Tenacity! Looks great !