Nice work! Good to see someone giving it a shot now that Mark Kock isn't doing it anymore.

Efiniracer,

can your shop make the carbon fiber airbox like the old M2 units? I think you could easily sell "10"

 

Am I the only one that thinks carbon fiber is tacky and ricey?

 

Yes!

 

efini--
thanks for the tips and great advice!! with all that being said, i think i might make one or two for myself and a friend, but leave it at that.

i'm sure molding the part is better, but are there any long-term ill-effects to draping it over the way i did (assuming i got everything else right)?

 

I"ll be making this part as well pretty soon by making a mold first.

But then again, I've been working with this material for over5 years now. Just be sure that if you use epoxy resin as stated above. Polyester will just cook of. Especially on your manifold and considering the underhood RX7 temperatures.

 

How do most carbon fiber hoods hold up to engine bay temps over the years? Are they susceptable to cracking? discoloring?

 

i did some more searching and found a zillion expoxy resins...

anyone got a link to a specific resin that would work well for this?

 

Junkie...

I would call Joel at Applied Vehicle Technology (317-546-6840 Indy). He would be able to help you out. I don't know if you are heat curing this, or if you are just curing at room temp, so he would be able to help you based on what you have or have access to. He also sells all the carbon and other fun things that you might want.
As far as long term problems? Tough call. With the Polyester resin, I am almost sure there will be some warpage and discoloration as well as not very strong. Using the right epoxy will give wonderful results, provided you cure it according to the manufacturers instructions. Some epoxies have very strict heat and pressure ramp cycles...

Check your pm's also....

 

efiniracer, thanks for that info..

I've also heard that there are epoxy with UV protection mixed in?? Have you tried these?? Otherwise, to avoid yellowing, you would need to shoot with clear.

I've recently purchased 10 yards of CF. Going to start with overlay and maybe try making something.. I've ordered some resins but haven't got here yet..

 

Discoloring of the hoods is mostly due to the fact that it has not the correct (or none at all) Clear coat/varnisch on it.
This needs to be UV resistant and of the 2 component family. You can not put just any clear coat/varnisch on an axposed part.

Mostly those hoods are not even real carbon but a glassfiber lookalike which they impregnate with polyester/vynilester resin, which itself is more sensitive to the impact of sunlight.

The strenght should be provided by an adequate subframe (glassfiber copy of the OEM is best)
As for disforming there is an item involved which I know as "tempering" a part.

In theory:

I have amold and make a glassfiber parts out of it. Ambient temperature 20°Celsius.
While the part cures, it warms (chemical reaction). Let's say it gets to 50° Celsius.

Now the parts is cured and released from the mold.
This part will not deform if exposed to temperature less than 50°C.
When the temperature does get higher (due to any possible reason) and the part is under stress (tight down, bolted under stress, bend, even under it's own weight) it will tkae the chape of that moment (part will deform untill unstressed).

Afterwards the cycle repeats itself. Every time the part gets warmer than the last , highest temp. it was exposed to AND is under stress, it will deform.

You can delay or minimize this effect by using apropriate resins for your aplication which will withstand this better. Epoxy is one of them.

Just to show. Automotive interior parts (plastics, glasfiber reinforced/based parts) like dashboards etc. are tested for deforming upto 90°Celsius.

My teacher (he builds parts for jet fighters) told me every high performance carbon part he makes is vacuum bagged and will be curing for 7 days in an oven at +- 120-130°C

 

speedworks,

Now I understand why people autoclave cf parts. It makes sense!! So, can you autoclave in any autoclaves?? I have an access to my work autoclaves which is used for medical waste and sterilization. Also, does it have to be completely dry?? I believe ours are steam based.

Also, any specific epoxy resins??

 

herblenny-
There is a world of differneces with a manufacturing (carbonfiber) autoclave, vs. a medical. The short answer is no, you cannot use that type of autoclave for your projects. Also, moisture when curing is a very bad thing. Look up the thread and you can see where to get the resins.

Speedworks-
I hope your teacher is curing in an autoclave and not just a vacuum bag and oven if these are being used for fighter aircraft!!

 

No those parts are used for his personal parts. For aircraft parts he has access to military equipment for production. I just wanted to indicate the importance of heat treating a part which will be under a specific load or stress.

I'm by no means an expert, just trying to contribute to the thread.