DIY wet-layup carbon fiber exterior/interior parts info

[TTkickedin]

Hey I've been seriously pondering making my own carbon fiber (cf) pieces, but everything I've been looking for are very old threads with images that dont exist anymore. Or, are to make a part that is nowhere near the size/complexity of the parts I will attempt to make in the near future.


The 300zx is a heavy machine. It also has a beautiful interior! This is a problem, and cf is the solution, (and a bit of its own problem);

GOOD: As you all know, cf allows you to minimize dead weight on your chassis without having to rip apart that nice leather interior. You also get the choice of lowering weight further by removing some unnecessary metal and stripping the interior out as well as sound deadening.

BAD: New CF production-ready parts can be very expensive. Most new that are inexpensive are usually made with poly-resin and/or graphite texalium. Unless you get severely weathered cf parts that are faded or cracking, there's no such thing as cheap production-made cf exterior parts simply because its a product that has a lot of customers who are willing to pay the high price of


Solution: I'm trying to minimize costs by making my own parts.

I'm very serious about this. I have experience in making my own wood products and have a little knowledge of fiberglass laying, so I''m not going at this completely blind. Just need some backup info!


With that said, my mission here is to make my own cf doors, hatch, fenders, T-Tops with no glass. If i get really good at making cf parts, im thinking of doing the dash completely of cf as well.

If you guys can help, please provide me with some information/links to this. Make sure those links actually have accompanying pictures!! hopefully this will become a very detailed write up for those of you who are interested as well.

Thanks!

[TTkickedin]

Bumpity Bump

I'd expect vig to know something about this, but don't talk me into buying that 'kit' of yours, lol. I'm looking into creating lightweight oem parts, that's pretty much it for now.

BUT, if this turns out to work in my favor and I can do this on the cheap, I might make my own carbon fiber front bumper styled like the IMPUL, greddy, and escort front bumper, or i might just make my own tasteful front, no ricer crap. I will let you guys know how it goes. I'm really serious about this!

If it really goes as well as i hope, Im hoping to do the whole car up with cf aside from the roof, wide fender overlays possibly?

I know its not entirely safe to do this but I dont plan on getting into an accident. If I do, idc i'll just keep making my own parts

[TTkickedin]

Did some more searching. I'm even more confused, but honestly i think its easy, its just getting down the technique that will be the hard part. This is why i will start by making fiberglass copies of each part i will create.

From what I've researched, I know for making fiberglass parts you will need to make a mold out of a variety of methods. Some people suggest high density foam, Some suggest chicken wire + paper mache or aluminum foil, some suggest styrofoam. From what I can come up with, chicken wire wouldnt be good because the shape wont be as intricate as i need it to be.

I can use high density foam, but how the hell do you perfectly mold a hood or full rear trunk lid mold out of that stuff? All of the diy write ups i found that actually have pictures are of small parts!

I'm sure theres somebody on here with more fiberglass/carbon fiber laying experience than I have that would be willing to lend advice. I insist on learning about this stuff, I won't stop with it until i have a completed product.

[NolimitZ32]

Ive actually researched making DIY injection molds, what I figured could be done is the part (hood or hatch) would be covered by a layer of polyethylene or some other strong plastic from either side (as if you were vacuum sealing it) then placed into a container (Big a** flat-screen box should work) on stilts to suspend the part. Then shoot it with the foam, you should be able to separate the 2 halves. This would yield a mold of the outside of the part from here you do some touch-up, cover it with latex epoxy for smoothness and voila. Like I said this is what I was going to do to try to make an injection mold for bumpers, side-skirts, and other misc body pieces (because I have fiberglass body parts. If you want to make something one-off custom you'd have to make the part in fiberglass first and then use that to make the molds. Hope this helps.

[TTkickedin]

I've been waiting all day for a reply, thanks! That's a really good one, i didn't even find any info on that from what i've been researching!

Hopefully i can find a big enough box today. if not ill just make one out of wood. id imagine i'll needa hell of a lot of foam too (worried about the price of that stuff)

i want to at least make a CF hood and trunk lid. Once i got those done and lookin good, i'd move onto doors with reinforcement for street use, and the ttops.

[TTkickedin]

This is the part that i dont understand. Say I did make the molds with the injection molding process right, and i made a fiberglass part on both sides of the mold. How does both sides bond to each other? Or maybe i'm overthinking the process?

[NolimitZ32]

Way beyond me, the process I described was a brainchild of mine, I've never seen it done but don't see any reason it shouldn't work, like I said I was planning this for bumpers and such other parts that don't have reinforcement or multiple 3 dimensional layers. I've never tested it.

[McShanks]

This is something I might be able to help you with. I have not worked with CF, but from what I understand, it is a similar process to Fiberglass. Let's start with a simple part, say... the oem side skirt. Find/fab 2 appropriate sized RIGID boxes, one will sit upside-down on top of the other like a lid and your part should just fit inside of the 2 put together. The top should be much shallower than the bottom, but still needs some depth to support the mold material. The goal here is to make a mold so you only need 2 parts of the mold. The side skirt cross section is kind of U-shaped (As it "curls" under the side and bolts under the door) so position it so that you can get the same shape by pulling the top half of the mold straight up and down. In this case, either like a u or like an n, much preferably, a u. The top of the part should be just BELOW the RIM of the bottom box so laying the cloth and resin can all be done in the bottom.

Coat the side skirt using vacuum shrinking or an appropriate coating that will ensure it does not stick to the mold material (preferred). Ensure whatever your mold material is, that it does not shrink or swell while settling (drying). This would make your life much more difficult. Place the part into the bottom half and fill with mold material until it JUST ABOUT reaches the top of the bottom half. Let is dry. Then, coat the whole top part of the mold material that is now dry with the "non-stick" compound you used on the part. Now, place the other box on top, then fill with mold material through holes or slots at the top. Having some sort of lip on the bottom box will help prevent a mess, and you want to ensure the 2 boxes fit together will and seal decently to avoid leakage/spillage. Once the mold material is settled, the two boxes should come apart easily, and the original part can be removed.

Now, you need to drill holes through the top mold down to where the part was so you have a means of injecting resin. You will want the holes to be close enough together that you will be able to push air out of the subsequent holes, and DEFINITELY want holes at the high points of the part where air bubbles will form. Coat the molds with whatever non-stick compound you need for the CF. Line the bottom part with the cloth and resin, using as many layers as needed. (Measure the thickness of the oem part and apply accordingly.) It might be a good idea to secure the cloth around the rim of the mold with small nails or pins to prevent the cloth from drifting, but be sure to drill matching holes in the lid box. You can always trim the excess, and you will have to regardless. Now CAREFULLY lower the lid box and ensure you have a good seal and it is lined up properly. Inject resin through the holes in the lid until the holes are full, starting at the "lowest" point or one end and working your way towards the "highest" point or the other end. Then, let it sit to dry.

Once it all has set and dried, carefully pull the top off, remove the pins and pull out your super-light Carbon Fiber oem part! You will have some trimming to do with a dremel, and make sure all the holes, slots, and grooves are located properly and mount holes reinforced if needed. This is how I would do Fiberglass, and CF SHOULD be similar. Please note, I have NEVER used CF, so I have no experience with how easy the resin and the cloth are to work with or anything like that. This should be a good start for you, try making some really small parts first like the center console storage lift panel or something. Hope this helps! If you try this, post pics and a step-by-step write up, because I may try this with CF a few years down the road....

*EDIT* Here is a useful link for more intricate parts (example for this is a tube): http://www.vaglinks.com/Docs/Misc/CarbonFiberHowTo2.pdf

[McShanks]

Holy... Crap... I hope you know what you are getting into price-wise... for 50" wide rolls of Carbon Fiber cloth, expect to pay over $100 per yard. So for 1 layer of CF cloth (probably need 2 to 3) a door panel will cost you over $200. For 3 layers, that's over $600! For both doors over $1200, etc. You get my drift. http://www.fibreglast.com/product/Prepr ... _03101/155

[TTkickedin]

Great information there, thank you!

Our hoods are relatively small, so pretty much the only thing to do here is get nothing less than 3 yards for anything exterior. s***, if the price for carbon fiber is that high, i wonder how the hell i can get it any cheaper. Hoods aren't THAT expensive I don't think.

Now does it have to be the prepreg stuff? there was another one there that wasn't AS expensive.

i found this website as well, i think it might not be real carbon fiber though, kinda like a texalium, carbon mix hence the low price. http://www.solarcomposites.com/composit ... on.html#1K

*EDIT* they keep mentioning carbon fiber composites, so what that is from my understanding Carbon Fiber Reinforced Plastic. They sell texalium separately.

[McShanks]

Now, the specifics of CF material is way beyond my expertise. I would recommend calling a rep from a CF company and telling them your goals. They should help you select the appropriate material. I looked at prepreg because it is supposed to be a bit stronger, and for a car body that might be better. BUT, i could be wrong, it may also be overkill. I just don't know. I wish I did. Hopefully, you can use less expensive stuff. I guess if they make parts out of fiberglass, even a lower grade CF should suffice. Good luck!

[TTkickedin]

Now, the specifics of CF material is way beyond my expertise. I would recommend calling a rep from a CF company and telling them your goals. They should help you select the appropriate material. I looked at prepreg because it is supposed to be a bit stronger, and for a car body that might be better. BUT, i could be wrong, it may also be overkill. I just don't know. I wish I did. Hopefully, you can use less expensive stuff. I guess if they make parts out of fiberglass, even a lower grade CF should suffice. Good luck!

I don't even think i'd even be able to afford Prepreg CF if I wanted to make cheaper parts. I think the CFRP that I found wouldn't be such a bad idea. They do make hoods outta that stuff.

Good thing is, I can buy a few yards of that CFRP and make a hood. If it ends up coming out too weak for daily driven automotive applications, I'm sure someone wanting to make a drift/autocross 300zx wouldnt mind having a cheap carbon fiber hood to play with and wreck. If it breaks, just keep replacing them! No harm no foul right? Hoods arent structural, and I dont even think our hatch is structural in any way (if it is, it must be a negligible amount of opposition force,) So I don't see how this could be a problem unless it was like rubber when you try to bend the part.

I can also make some interior pieces out of the weaker stuff if theres enough left over. Time will tell. I'll be revisiting this thread from time to time to dump some more research i've come up with., and hopefully build pics. I think this is feasible, wet layup or vacuum forming (i think that's what it's called.)

Thanks for the support guys


*EDIT* http://www.woodward-aerospace.com/carbo ... epreg.html

I think prepreg is the strongest carbon fiber you can buy. I think that would be suitable for chassis parts or something, external parts excluding doors, i don't think would be such a problem. But that article says how to make prepreg though.If anything, I can make my own prepreg too

[TTkickedin]

OR, instead of prepreg (or doubled with prepreg) I can get Kevlar fabric to combine with the regular twill CF fabric. I think there's a lot of routes I can take for this type of thing. I've estimated that 3 yards (good enough for the hood,) of regular twill will be 90 dollars. 1 Yard of kevlar would be 35 dollars. Epoxy resin and the expanding foam for the mold (that is if i even make one) Cant be more than 50-100. Thats a roughly a 235 Dollar Carbon/Kevlar hood